Route 7 Connector Ramp MODIF IE D I N T ER C H A N G E M OD IFICATIO N R E PO RT TRA N S F O R M I : I N S ID E THE BE LTWAY

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1 STATE PROJECT NUMBER: A-493,P101, C501, B686; UPC: FEDERAL PROJECT NUMBER: NHPP-066-1(356) FAIRFAX COUNTY, VIRGINIA TRA N S F O R M I : I N S ID E THE BE LTWAY Route 7 Connector Ramp MODIF IE D I N T ER C H A N G E M OD IFICATIO N R E PO RT A UG UST 2017

2 TABLE OF CONTENTS EXECUTIVE SUMMARY... 1 ES.1 Project Background... 1 ES.2 Purpose and Need... 1 ES.3 Screening of Alternatives... 1 ES.4 Proposed Actions in the Preferred Alternative... 2 ES.5 Summary of Findings... 4 ES.5.1 Traffic Operational Analysis Findings... 4 ES.5.2 Safety Analysis Findings INTRODUCTION Project Background Purpose and Need Project Location and Study Area Relationship to Other Highway Improvement Plans/Projects Transform 66 Outside the Beltway Transform 66 Inside the Beltway Tolling Transform 66 Inside the Beltway Eastbound Widening Report Organization RESPONSES TO FHWA 8-POINT POLICY ON INTERSTATE HIGHWAY ACCESS MODIFICATIONS Policy Point 1: Need for Access Point Revision Policy Point 2: Reasonable Alternatives Policy Point 3: Operational and Collision Analyses Policy Point 4: Access Connections and Design Policy Point 5: Land Use and Transportation Plans Policy Point 6: Future Interchanges Policy Point 7: Coordination Policy Point 8: Environmental Processes METHODOLOGY Study Area Analysis Years And Scenarios Data Collection Travel Demand Forecasting i

3 3.5 Traffic Operational Analysis Safety Analysis PREFERRED ALTERNATIVE No-Build Alternative Transportation System Management Options Build Alternatives Option 1: At-Grade Intersection Connector Option 2: Direction Connector Ramp Alternative Evaluations Preliminary Operational Analysis Preliminary Safety Analysis Compliance with Design Criteria Preliminary Cost Estimates Other Impacts Evaluation Matrix Roadway Geometry of the Preferred Alternative Conceptual Roadway Geometry Design Design Exceptions and Design Waivers Conceptual Signing Plan EXISTING TRAFFIC CONDITIONS Existing Traffic Volumes Existing Peak-Hour Traffic Volumes Traffic Estimation on the Proposed Connector Ramp Existing Traffic Operations and Congestion Levels Baseline VISSIM Model Development and Validation Traffic Operations Results ASSESSMENT OF FUTURE TRAFFIC CONDITIONS Overview of No-Build and Build Conditions No-Build Conditions Build Conditions Interim Year Analysis Traffic Volumes No-Build vs. Build Operations Summary of 2025 Operations Design Year Analysis ii

4 Traffic Volumes No-Build vs. Build Operations Summary of 2040 Operations SAFETY AND CRASH ANALYSIS Data Collection and Analysis Methodology Historical Crash Analysis for Existing Condition Study Area Crash Frequency and Trend Summary Safety Focus Area Crash Frequency and Trend Summary Expected Safety Impact of Build Option on the Safety Focus Area Evaluation Based on Historical Crash Data Evaluation Based on HSM analysis Summary and Conclusion APPENDICES Appendix A: Justification of Need Technical Memorandum Appendix B: Framework Document for Traffic Operations and Safety Report (Interchange Modification Report Light) Appendix C: Estimates of Ramp Volumes Technical Memorandum Appendix D: Detailed Traffic Operational Analysis Results in the Existing and Future Conditions Appendix E: Roadway Design Criteria and Geometric Data Summary Appendix F: Roadway Profile Sheets iii

5 LIST OF TABLES Table 3.1: MOE Thresholds for Congestion Levels Table 4.1: Eastbound I-66 Ramps at Route 7 Traffic Operations, 2025 and 2040 PM Peak Hours Table 4.2: Intersection Delays and Levels of Congestion, 2025 PM Peak Hour Table 4.3: Intersection Delays and Levels of Congestion, 2040 PM Peak Hour Table 4.4: Queue Lengths at the Eastbound I-66 Off-Ramp to Route 7, 2025 and 2040 PM Peak Hours 4-9 Table 4.5: Comparisons of Predicted Crashes on C-D Road Segment Table 4.6: Potential Design Exceptions and Waivers in Option 1C Table 4.7: Potential Design Exceptions and Waivers in Option 2B (Preferred Alternative) Table 4.8: Evaluation Matrix for Build Options Table 5.1: Traffic from Eastbound I-66 to West Falls Church Metro/Haycock Road Table 5.2: Eastbound I-66 Ramps at Route 7 Traffic Operations 2016 AM Peak Hour Table 5.3: Eastbound I-66 Ramps at Route 7 Traffic Operations 2016 PM Peak Hours Table 5.4: Comparison of 2016 Model Travel Times with Field Travel Times AM Peak Hour Table 5.5: Comparison of 2016 Model Travel Times with Field Travel Times PM Peak Hour Table 5.6: Intersection Delay and Congestion Level during Existing AM and PM Peak Hour Table 6.1: Peak-Hour Traffic Volumes on the Proposed Connector Ramp Interim Year Table 6.2: Eastbound I-66 Ramps at Route 7 Traffic Operations 2025 No-Build AM Peak Hour Table 6.3: Eastbound I-66 Ramps at Route 7 Traffic Operations 2025 Build AM Peak Hour Table 6.4: Eastbound I-66 Ramps at Route 7 Traffic Operations 2025 No-Build PM Peak Hour Table 6.5: Eastbound I-66 Ramps at Route 7 Traffic Operations 2025 Build PM Peak Hour Table 6.6: Queue Lengths at the Eastbound I-66 Off-Ramp to Route No-Build vs. Build Scenarios Table 6.7: Average Travel Times to West Falls Church Metro 2025 No-Build vs. Build Scenarios Table 6.8: Intersection Delay and Congestion Levels on Intersections 2025 AM Peak Hour Table 6.9: Intersection Delay and Congestion Levels on Intersections 2025 PM Peak Hour Table 6.10: Estimated Traffic Volumes on the Proposed Connector Ramp Design Year Table 6.11: Eastbound I-66 Ramps at Route 7 Traffic Operations 2040 No-Build AM Peak Hour Table 6.12: Eastbound I-66 Ramps at Route 7 Traffic Operations 2040 Build AM Peak Hour Table 6.13: Eastbound I-66 Ramps at Route 7 Traffic Operations 2040 No-Build PM Peak Hour Table 6.14: Eastbound I-66 Ramps at Route 7 Traffic Operations 2040 Build PM Peak Hour Table 6.15: Queue Lengths at the Eastbound I-66 Off-Ramp to Route No-Build vs. Build Scenarios Table 6.16: Average Travel Times to West Falls Church Metro 2040 No-Build vs. Build Scenarios Table 6.17: Intersection Delay and Congestion Levels during 2040 No-Build and Build AM Peak Hour Table 6.18: Intersection Delay and Congestion Levels during 2040 No-Build and Build PM Peak Hour Table 7.1: Crash Summary by Roadway Segment and Severity within the General Study Area Table 7.2: Total Crash Summary by Severity by Safety Focus Area Table 7.3: Total Crash Frequencies for Existing Condition and Potential for Safety Improvement (PSI) Table 7.4: Crash Frequencies Summary for No-Build and Build Conditions in Table 7.5: Crash Frequencies Summary for No-Build and Build Conditions in iv

6 Table 7.6: Crash Frequencies Summary by Ramp for No-Build and Build Conditions in Table 7.7: Crash Frequencies Summary by Ramp for No-Build and Build Conditions in Table 7.8: AADT and Estimated Crash Frequencies at Route 7 and Haycock Road Intersection for 2040 No-Build and Build Conditions v

7 LIST OF FIGURES Figure ES.1: Conceptual Layout of the Preferred Alternative... 3 Figure 1.1: Proposed Connector Ramp on Eastbound I-66 Exit Figure 1.2: Project Location Figure 3.1: Eastbound I-66 Exit 66 Route 7 Connector Ramp Traffic Study Area Figure 4.1: Lane Configurations of No-Build Alternative Figure 4.2: Lane Configurations of Build Alternative Option 1A Two-Lane Ramp Figure 4.3: Simulated Option 1A Ramp Queuing Conditions Figure 4.4: Lane Configurations of Build Alternative Option 1B Three-Lane Ramp Figure 4.5: Simulated Option 1B Ramp Queuing Conditions Figure 4.6: Lane Configurations of Build Alternative Option 1C Four-Lane Ramp Figure 4.7: Lane Configurations of Build Alternative Option 2A Choice Lane Figure 4.8: Lane Configurations of Build Alternative Option 2B Dedicated Lane Figure 4.9: Eastbound I-66 Travel Times to the Metro Station, 2025 and 2040 PM Peak Hours Figure 4.10: Preliminary Conceptual Plan of the Preferred Alternative (Sheet 1 of 2) Figure 4.11: Preliminary Conceptual Plan of the Preferred Alternative (Sheet 2 of 2) Figure 4.12: Conceptual Signing Plan (Sheet 1 of 2) Figure 4.13: Conceptual Signing Plan (Sheet 2 of 2) Figure 5.1: Existing Year (2016) Peak Hour Traffic Freeway and Ramp Volumes Figure 5.2: Existing Year (2016) Peak Hour Traffic Arterial Intersection Turning Volumes Figure 5.3: Freeway and Ramp Congestion Map 2016 AM Peak Hour Figure 5.4: Freeway and Ramp Congestion Map 2016 PM Peak Hour Figure 5.5: Travel Time Trajectories Comparison 2016 AM Peak Hour Figure 5.6: Travel Time Trajectory Comparison 2016 PM Peak Hour Figure 6.1: Interim Year (2025) Peak-Hour Traffic Demand Volumes on Freeway and Ramp Figure 6.2: Interim Year (2025) Peak-Hour Traffic Demand at Intersections on Route Figure 6.3: Freeway and Ramp Congestion Map 2025 No-Build AM Peak Hour Figure 6.4: Freeway and Ramp Congestion Map 2025 Build AM Peak Hour Figure 6.5: Freeway and Ramp Congestion Map 2025 No-Build PM Peak Hour Figure 6.6: Freeway and Ramp Congestion Map 2025 Build PM Peak Hour Figure 6.7: Design Year (2040) Peak-Hour Traffic Demand Volumes on Freeway and Ramp Figure 6.8: Design Year (2040) Peak-Hour Traffic Demand at Intersections on Route Figure 6.9: Freeway and Ramp Congestion Map 2040 No-Build AM Peak Hour Figure 6.10: Freeway and Ramp Congestion Map 2040 Build AM Peak Hour Figure 6.11: Freeway and Ramp Congestion Map 2040 No-Build PM Peak Hour Figure 6.12: Freeway and Ramp Congestion Map 2040 Build PM Peak Hour Figure 7.1: Historical Crash Data Collection Area Figure 7.2: Total Crash Summary by Collision Type Figure 7.3: Study Area of HSM Safety Analysis Figure 7.4: Route 7 and Haycock Road Intersection Crash Summary by Severity Figure 7.5: Route 7 and Haycock Road Intersection Crash Summary by Collision Type Figure 7.6: Crash Summary of Focus Ramp Areas by Severity Figure 7.7: Crash Summary of Focus Ramp Areas by Collision Type vi

8 EXECUTIVE SUMMARY ES.1 PROJECT BACKGROUND The West Falls Church Metrorail station (herein referenced as Metro station ), located adjacent to the Interstate 66 (I-66) and Route 7 interchange in Fairfax County, Virginia, does not have direct access from eastbound I-66. Currently, to get to the Metro station from eastbound I-66, motorists take the Exit 66 and merge onto already congested Route 7 toward Falls Church, turn left at the Haycock Road intersection located about 1,500 feet downstream of the exit ramp, and then turn left onto Falls Church Drive. VDOT is proposing a new connector ramp between Ramp A (southbound Route 7 to eastbound I-66 and Metro station/uva-vt campus) and Ramp B (eastbound I-66 to southbound Route 7 toward Falls Church). The proposed connector ramp will provide a direct access path for vehicles from eastbound I-66 to the Metro station and UVA-VT campus. This project will be constructed as part of the I-66 Inside the Beltway (ITB) Eastbound Widening project starting in 2018 and is expected to open to traffic in late ES.2 PURPOSE AND NEED The purpose of the proposed connector ramp is to enhance multimodal connectivity along the I-66 corridor by providing direct access for vehicles from eastbound I-66 to the West Falls Church Metrorail station. Potential benefits of the proposed connector ramp are as follows: Direct connectivity for vehicles to the Metro station from eastbound I-66. By diverting vehicles off Route 7 and Haycock Road to reach the Metro station, the operational performance of the intersections on these roadways will be improved. The diversion will improve safety by reducing the unsafe weaving maneuvers associated with vehicles exiting eastbound I-66 and performing multiple lane changes in a short distance to turn left at Haycock Road. ES.3 SCREENING OF ALTERNATIVES In addition to the No-Build Alternative, VDOT developed and evaluated Build alternatives based on reasonable design refinements that met the project s purpose and need. Through discussions with project stakeholders, VDOT initially identified a preliminary set of refinements and considered two alternatives for further analysis and evaluation. The Build alternatives include: Option 1: Adding through movement at eastbound I-66 off-ramp terminal intersection at Route 7. Option 2: Providing direct access from eastbound I-66 off-ramp. In consideration of the impacts of both options presented above, as well as discussion with localities and other stakeholders, VDOT selected Option 2 as the Preferred Build Alternative because it best addressed the purpose and need of the project. Option 2 provides direct access to the Metro station, reduces the queue spill back on eastbound I-66 mainline, while operating at or better than the No-Build condition. The direct connection also improves travel reliability for vehicles and potential transit buses that are destined to the Metro station from eastbound I-66. Transform Interstate 66 August 2017 ES-1

9 Route 7 Connector Ramp: Modified Interchange Modification Report ES.4 PROPOSED ACTIONS IN THE PREFERRED ALTERNATIVE This project proposes to add a new connector ramp between Ramp A (southbound Route 7 to eastbound I- 66 and Metro station/uva-vt campus) and Ramp B (eastbound I-66 to southbound Route 7 toward Falls Church). The Preferred Alternative includes the following improvements: Extend the eastbound off-ramp at Exit 66 beyond the Barbour Road overpass. Add a second deceleration lane of 405 feet long at the eastbound off-ramp of Exit 66. Add a new connector ramp (Ramp W) of about 560 feet long to connect the existing Ramp B and Ramp A. Add an auxiliary lane on Ramp A of 455 feet long as the merge area which extends 200 feet downstream of the existing Ramp B overpass bridge on Route 7. Figure ES.1 illustrates the conceptual layout of the Preferred Build Alternative. August 2017 Transform Interstate 66 ES-2

10 Route 7 Connector Ramp: Modified Interchange Modification Report Figure ES.1: Conceptual Layout of the Preferred Alternative Transform Interstate 66 August 2017 ES-3

11 Route 7 Connector Ramp: Modified Interchange Modification Report ES.5 SUMMARY OF FINDINGS ES.5.1 Traffic Operational Analysis Findings The Preferred Alternative will divert traffic from the southbound Route 7 left-turn movement at the Haycock Road intersection to the proposed connector ramp. Traffic operations analysis using microsimulation modeling shows consistent results in the interim year (2025) and design year (2040). In both years, the eastbound I-66 ramp segments will experience similar levels of congestion between the No- Build and Build scenarios. The proposed connector ramp will operate at little or no congestion in the 2040 AM and PM peak hours. The new connector ramp reduces the travel time from eastbound I-66 to the West Falls Church Metrorail station by about percent in both the AM and PM peak hours. All the intersections on Route 7 and Haycock Road in the study area operate at similar congestions levels in both the No-Build and Build scenarios. The overall intersection delay at Route 7 and Haycock Road reduces in the Build scenario due to traffic diverted to the new connector ramp. In conclusion, the Preferred Alternative in the Build conditions is anticipated to have minimal impacts on the freeway and interchange system without degradation in operational conditions. Microsimulation modeling also confirms the benefits of the Preferred Alternative in the form of reduced travel times to the West Falls Church Metrorail station and reduced delays along local arterials, especially at the Route 7 and Haycock Road intersection. ES.5.2 Safety Analysis Findings The five-year crash data identifies the Route 7 corridor and the intersection of Route 7 and Haycock Road as a high-frequency crash area. The predominant crash types at these locations were rear-end and angle collision. A possible contributing factor for these types of crashes is severe congestion and a large amount of traffic choosing the intersection to go to the West Falls Church Metrorail station. A calculation of the predicted impact of the freeway and ramps indicates minimal impact on the freeway and an expected 9 percent higher crash frequency for the ramps. However, based on the review of existing crash data, there were very few crashes on the ramps, and the expected crash frequency was lower than the predicted result for the existing conditions indicating the ramp is currently performing better than other peer sites. It is expected that the impact on the ramps should be largely offset by the congestion relief on local streets. A reduction in traffic volumes would have a benefit of at least 5 percent reduction in crashes at the Route 7 and Haycock Road intersection alone, illustrating the anticipated benefit to the arterial roadway system. The evaluation of the local system was limited to one intersection only, therefore the anticipated benefit would likely be greater if considering the entire section of roadway along the current travel path of the diverted vehicles. In conclusion, the Preferred Alternative in the Build conditions is predicted to have minimal negative safety impacts within the study area, and adverse impacts would be expected to be minor within the interchange based on the existing condition and the quantitative analysis. While it cannot be specifically quantified, based on the comparisons of the crash data and predicted crash frequency between the Build and No-Build conditions, the reduction in crashes as a result of diverting traffic from the heavily congested and complex arterial system is anticipated to exceed the slight increase in predicted crashes as a result of the addition of the ramp connector. August 2017 Transform Interstate 66 ES-4

12 1. INTRODUCTION 1.1 PROJECT BACKGROUND The West Falls Church Metrorail station (herein referenced to as Metro station ), located adjacent to the Interstate 66 (I-66) and Route 7 interchange in Fairfax County, currently does not have direct access from eastbound I-66. Figure 1.1 shows the path utilized by vehicles to get to the Metro station. Vehicles exit eastbound I-66 at Route 7, turn right and head south on Route 7 toward Falls Church, then turn left at the Haycock Road intersection located about 1,500 feet downstream of the I-66 exit, and then turn left onto Falls Church Drive. VDOT is proposing a new connector ramp between Ramp A (southbound Route 7 to eastbound I-66 and Metro station/uva-vt campus) and Ramp B (eastbound I-66 to southbound Route 7 toward Falls Church) as shown in Figure 1.1. The proposed connector ramp will provide a direct access path for vehicles from eastbound I-66 to the Metro station and UVA-VT campus as shown by the blue dashed line in Figure 1.1. This project will be constructed as part of the I-66 Inside the Beltway (ITB) Eastbound Widening project starting in 2018 and is expected to open to traffic in late Therefore, the traffic and safety analysis for this project will be built upon and consistent with the Traffic and Transportation Technical Report (TaTTR) for the Eastbound Widening project. 1.2 PURPOSE AND NEED The purpose of the proposed connector ramp is to enhance multimodal connectivity along the I-66 corridor by providing direct access for vehicle from eastbound I-66 to the West Falls Church Metro station. Potential benefits of the proposed connector ramp are as follows: Direct connectivity for vehicles to the Metro station from eastbound I-66. By diverting vehicles off Route 7 and Haycock Road to reach the Metro station, the operational performance of the intersections on these roadways will be improved. The diversion will improve safety by reducing the unsafe weaving maneuvers associated with vehicles exiting eastbound I-66 and performing multiple lane changes in a short distance to turn left at Haycock Road. Appendix A documents the detailed Justification of Need. 1.3 PROJECT LOCATION AND STUDY AREA As illustrated in Figure 1.2, the project is located in Fairfax County, just north of the City of Falls Church, Virginia. The extended study areas for traffic operations and safety analysis are discussed in detail in Chapter 3. Transform Interstate 66 August

13 Route 7 Connector Ramp: Modified Interchange Modification Report Figure 1.1: Proposed Connector Ramp on Eastbound I-66 Exit 66 August 2017 Transform Interstate

14 Route 7 Connector Ramp: Modified Interchange Modification Report Figure 1.2: Project Location Transform Interstate 66 August

15 Route 7 Connector Ramp: Modified Interchange Modification Report 1.4 RELATIONSHIP TO OTHER HIGHWAY IMPROVEMENT PLANS/PROJECTS The proposed project is adjacent to or overlaps with a number of other on-going highway improvement projects. These projects are listed and described in detailed below: Transform 66 Outside the Beltway Transform 66 Inside the Beltway Tolling Transform 66 Inside the Beltway Eastbound Widening Transform 66 Outside the Beltway The I-66 Outside the Beltway project is a public-private partnership between the Virginia Department of Transportation (VDOT) and the Virginia Department of Rail and Public Transportation (DRPT) and a private partner to construct and operate 22.5 miles of new Express Lanes alongside three general purpose lanes on I-66 from I-495 to University Boulevard in Gainesville. Express Lanes will be dynamically tolled to manage demand for the lanes and provide a reliable, faster trip. The project also includes: New and improved bus service and transit routes. New and expanded park-and-ride lots providing convenient access to the Express Lanes and more than 4,000 new park-and-ride spaces. Interchange improvements to enhance safety and reduce congestion, including auxiliary lanes between interchanges, where needed. The construction will begin in 2018, and the current anticipated completion date of this project is July, Transform 66 Inside the Beltway Tolling The I-66 Inside the Beltway Tolling project is to remove the current restrictions on single-occupancy vehicles (SOVs) during restricted periods and charge them a demand and distance-based toll. The tolling infrastructure is currently under construction and the peak-period/peak-direction tolling will commence late Transform 66 Inside the Beltway Eastbound Widening The I-66 Inside the Beltway Eastbound Widening project is to construct an additional eastbound lane along approximately four miles of eastbound I-66 from the Dulles Connector Road (Route 267) in Fairfax County to Fairfax Drive in the Ballston area of Arlington County, Virginia. The purpose of this improvements is to increase capacity in order to improve traffic operations, reduce congestion, and address safety needs. Construction is expected to start in 2018 and open to traffic in late REPORT ORGANIZATION The report is organized in the following order: 1. Introduction to describe project background, purpose and need and location. 2. Responses to FHWA 8-Point Policy on Interstate Highway Access Modifications to summarize the discussion on the compliance of each of eight FHWA interstate access policy requirements for the proposed connector ramp. 3. Methodology to identify data collection, assumptions, alternative development and scenarios that drive the travel demand forecasting steps, traffic operational analysis, and safety and crash analysis. August 2017 Transform Interstate

16 Route 7 Connector Ramp: Modified Interchange Modification Report 4. Preferred Alternative to present the discussion on the development of ramp alternatives along with the preliminary operational analysis and other factors that drive the selection of a preferred alternative. 5. Existing Traffic Operational Conditions to understand the character of existing traffic and travel patterns as well as the performance of traffic operations. 6. Assessment of Future Conditions to present the details on the development of future traffic demand for 2025 and 2040 analysis years along with the operational results and findings of No- Build and Build scenarios. 7. Safety and Crash Analysis to present the existing conditions and an assessment of future conditions using Highway Safety Manual (HSM) methods within the Enhanced Interchange Safety Analysis Tool (ISATe). Transform Interstate 66 August

17 2. RESPONSES TO FHWA 8-POINT POLICY ON INTERSTATE HIGHWAY ACCESS MODIFICATIONS FHWA s Policy on Access to the Interstate System provides the requirements necessary to justify or substantiate any proposed changes in access to the Interstate System. The eight specific policy requirements are shown below with a response for each concerning the proposed connector ramp at the eastbound I-66 off-ramp at Route 7 (Leesburg Pike) to access West Falls Church Metro station and the UVA-VT Northern Virginia Center campus at Exit 66. st It is in the national interest to preserve and enhance the Interstate System to meet the needs of the 21P P Century by assuring that it provides the highest level of service in terms of safety and mobility. Full control of access along the Interstate mainline and ramps, along with control of access on the crossroad at interchanges, is critical to providing such service. Therefore, FHWA's decision to approve new or revised access points to the Interstate System must be supported by substantiated information justifying and documenting that decision. The FHWA's decision to approve a request is dependent on the proposal satisfying and documenting the following requirements. 2.1 POLICY POINT 1: NEED FOR ACCESS POINT REVISION The need being addressed by the request cannot be adequately satisfied by existing interchanges to the Interstate, and/or local roads and streets in the corridor can neither provide the desired access, nor can they be reasonably improved (such as access control along surface streets, improving traffic control, modifying ramp terminals and intersections, adding turn bays or lengthening storage) to satisfactorily accommodate the design-year traffic demands (23 CFR 625.2(a)). The proposed project is not a new facility or access point but a modification to the configuration of an existing ramp. The proposed modification to the eastbound I-66 off-ramp to Route 7 (Exit 66) includes converting the existing single-lane exit ramp to a two-lane exit ramp and providing a connector ramp spur to go to the Metro station. Due to the constrained environment, there are limited options to provide alternate improvements on Route 7. An alternative was proposed to improve the Metro station access by adding a through- lane at the eastbound I-66 off-ramp terminal intersection with Route 7. However, this alternative was dropped after comprehensive evaluation of traffic operations, safety, roadway design, and cost estimates. Chapter 4 includes the detailed discussion on alternative evaluation, comparisons and selection. The proposed connector ramp will help improve the flow of traffic at the eastbound I-66/Route 7 exit ramp and will accommodate the design-year traffic demand at this exit while also providing a more direct access for vehicles traveling from I-66 to the existing the Metro station. 2.2 POLICY POINT 2: REASONABLE ALTERNATIVES The need being addressed by the request cannot be adequately satisfied by reasonable transportation system management (such as ramp metering, mass transit, and HOV facilities), geometric design, and alternative improvements to the Interstate without the proposed change(s) in access (23 CFR 625.2(a)). The proposed improvements are considered a geometric improvement to an existing ramp to provide improved operation for the I-66 eastbound movement through this interchange and a direct access to the Metro station thereby reducing traffic headed to Route 7. By providing a two-lane exit, more intrusive improvements at this location, such as a total reconstruction of the interchange, are avoided. I-66 is currently an HOV 2+ only facility in the eastbound direction in the AM peak period. It will be converted to an Express Lanes with HOV 2+ riders using the facility for free during the AM peak period. There is a proposal to Transform Interstate 66 August

18 Route 7 Connector Ramp: Modified Interchange Modification Report convert the HOV 2+ restriction to HOV 3+ and the traffic analysis and the corresponding traffic forecasts for the design year account for this change. Under the current conditions, the eastbound I-66 vehicles have to exit to southbound Route 7 and then navigate through the local street network to access the Metro station. This adds additional burden to Route 7 and to the ramp intersection at the I-66 interchange. Additional Transportation System Management and transit alternatives, while important elements in any planning, will not adequately address the need for capacity or improve operations on the ramp. 2.3 POLICY POINT 3: OPERATIONAL AND COLLISION ANALYSES An operational and safety analysis has concluded that the proposed change in access does not have a significant adverse impact on the safety and operation of the Interstate facility (which includes mainline lanes, existing, new, or modified ramps, ramp intersections with crossroad) or on the local street network based on both the current and the planned future traffic projections. The analysis shall, particularly in urbanized areas, include at least the first adjacent existing or proposed interchange on either side of the proposed change in access (23 CFR 625.2(a), (d) and (f)). The crossroads and the local street network, to at least the first major intersection on either side of the proposed change in access, shall be included in this analysis to the extent necessary to fully evaluate the safety and operational impacts that the proposed change in access and other transportation improvements may have on the local street network (23 CFR 625.2(a) and (d)). Requests for a proposed change in access must include a description and assessment of the impacts and ability of the proposed changes to safely and efficiently collect, distribute and accommodate traffic on the Interstate facility, ramps, intersection of ramps with crossroad, and local street network (23 CFR 625.2(a) and (d)). Each request must also include a conceptual plan of the type and location of the signs proposed to support each design alternative (23 U.S.C. 109(d) and 23 CFR (d)). A detailed traffic operational analysis was conducted for typical weekday AM and PM peak-hour conditions for the Transform 66: Inside the Beltway, Eastbound Widening project under the TaTTR using VISSIM microsimulation. For the design year (2040), the demand for the eastbound I-66 off-ramp to Route 7 is more than 40 percent higher in the AM peak (peak direction) under the Build conditions compared to the existing conditions. This amounts to an increase of 26 percent more traffic from eastbound I-66 going to southbound Route 7. It is projected that the intersection of Route 7 and Haycock Road/Shreve Road that is used to access the Metro station will degrade from the existing LOS D to a LOS F in 2040 with no improvements. This will increase delays for traffic from eastbound I-66 trying to access the Metro station. With the proposed modifications, the traffic operations analysis detailed in Chapter 5 and Chapter 6 indicate that access to the Metro station will be greatly improved while maintaining the speeds and densities along I-66 mainline in the vicinity of this ramp compared to the 2040 No-Build conditions. The same is true for the travel times and throughputs in this segment. Thus, the modification proposed for the Exit 66 ramp will not have a negative impact on operations of the mainline freeway segments and the corresponding ramp intersection with the crossroad. Chapter 6 includes a detailed operations analysis of the study area including the Exit 66 ramp. A combination of qualitative and quantitative analyses was used to evaluate safety of the study area and the proposed improvements. The five-year crash data identifies the Route 7 corridor and the intersection of Route 7 with Haycock Road as a high-frequency crash area. The safety analysis indicates that the total crashes along Route 7 within the study area are much higher as compared to the crashes along I-66 at the interchange, the ramps, or along Haycock Road. For the intersection of Route 7 with Haycock Road, the August 2017 Transform Interstate

19 Route 7 Connector Ramp: Modified Interchange Modification Report crash types indicate high volumes and significant left-turn volume as a factor. With the proposed connector ramp, traffic will be diverted from the local arterial routes to the new connector ramp to access the Metro station. The reduced volume at the intersection of Route 7 with Haycock Road would relieve the congestion and potential crashes caused by those vehicles turning left to Haycock Road. Along the freeway segments, based on the ISATe and HSM prediction methods, it was found that compared to the predicted No-Build conditions, freeway segments under the proposed Build conditions have almost the same performance for both 2025 and 2040 analysis years. For the intersection of Route 7 with Haycock Road, using the HSM methods to approximate the benefits, it was found that the estimated number of predicated crashes per year are four (4) percent lower under the Build conditions compared to the No-Build conditions. The Preferred Alternative in the Build condition is predicted to have minimal negative safety impacts within the study area, and adverse impacts would be expected to be minor within the interchange based on the existing condition and the quantitative analysis. While it cannot be specifically quantified, based on the comparisons of the crash data and predicted crash frequency between the Build and No-Build conditions, the reduction in crashes as a result of diverting traffic from the heavily congested and complex arterial system is anticipated to exceed the slight increase in predicted crashes as a result of the addition of the ramp connector. Chapter 7 includes a detailed safety and crash analysis of the study area including the Exit 66 ramp. 2.4 POLICY POINT 4: ACCESS CONNECTIONS AND DESIGN The proposed access connects to a public road only and will provide for all traffic movements. Less than full interchanges may be considered on a case-by-case basis for applications requiring special access for managed lanes (e.g., transit, HOVs, HOT lanes) or park and ride lots. The proposed access will be designed to meet or exceed current standards (23 CFR 625.2(a), 625.4(a)(2), and (d)). The current interchange is considered a full interchange as it accommodates all traffic movements. The proposed modification to the ramp only converts the existing one-lane exit to a two-lane exit and provides improvement to the operations and safety for the I-66 eastbound exit ramp while maintaining all other existing movements. In addition, this proposed modification also provides a more direct access for those vehicles travelling from I-66 eastbound and Route 7 southbound to the Metro station. All the existing access and proposed modifications of this interchange connect to public roads only. There are three potential Design Waivers and no Design Exceptions for the Preferred Alternative. They are listed and discussed in Chapter POLICY POINT 5: LAND USE AND TRANSPORTATION PLANS The proposal considers and is consistent with local and regional land use and transportation plans. Prior to receiving final approval, all requests for new or revised access must be included in an adopted Metropolitan Transportation Plan, in the adopted Statewide or Metropolitan Transportation Improvement Program (STIP or TIP), and the Congestion Management Process within transportation management areas, as appropriate, and as specified in 23 CFR part 450, and the transportation conformity requirements of 40 CFR parts 51 and 93. The proposed interchange modifications consider and are consistent with local land use and transportation plans. The Metropolitan Washington Council of Governments (MWCOG) has determined that this project is not regionally significant for Air Quality Conformity Analysis. The ramp modification project has been grouped in the TIP/STIP. Transform Interstate 66 August

20 Route 7 Connector Ramp: Modified Interchange Modification Report 2.6 POLICY POINT 6: FUTURE INTERCHANGES In corridors where the potential exists for future multiple interchange additions, a comprehensive corridor or network study must accompany all requests for new or revised access with recommendations that address all of the proposed and desired access changes within the context of a longer-range system or network plan (23 U.S.C. 109(d), 23 CFR 625.2(a), (d), and ). The proposed project only modifies an existing ramp within the existing interchange footprint. This is a highly saturated corridor with limited right-of-way for future interchanges or reconfigurations and no new access has been identified in the region s Constrained Long-Range Plan (CLRP) within this corridor. Notwithstanding the foregoing, this project will not preclude proposed interchanges or improvements at other locations along the corridor. 2.7 POLICY POINT 7: COORDINATION When a new or revised access point is due to a new, expanded, or substantial change in current or planned future development or land use, requests must demonstrate appropriate coordination has occurred between the development and any proposed transportation system improvements (23 CFR 625.2(a) and (d)). The request must describe the commitments agreed upon to assure adequate collection and dispersion of the traffic resulting from the development with the adjoining local street network and Interstate access point (23 CFR 625.2(a) and (d)). The proposed modifications to the Exit 66 ramp are part of the Transform 66: Inside the Beltway, Eastbound Widening project and are being considered as an improvement at an existing interchange to support the overall project needs including access to transit and to support the regional growth. The needs for the I-66 eastbound widening component of the Transform 66: Inside the Beltway improvements program initiative were initially identified in the I-66 Multimodal Study Inside the Beltway report and have been further considered in greater detail in the Environmental Assessment (EA) process. The proposed modifications are necessary to mitigate these needs and have been included in the MWCOG s Constrained Long-Range Transportation Plan (CLRP). They have been developed after detailed coordination and discussions with the local jurisdictions including representatives from Fairfax County, Arlington County and the City of Falls Church. 2.8 POLICY POINT 8: ENVIRONMENTAL PROCESSES The proposal can be expected to be included as an alternative in the required environmental evaluation, review, and processing. The proposal should include supporting information and current status of the environmental processing (23 CFR ). A Categorical Exclusion document has been prepared and has been submitted to FHWA. The Categorical Exclusion document was approved by FHWA in June August 2017 Transform Interstate

21 3. METHODOLOGY This chapter summarizes the study area, assumptions, and methodology for traffic operations and safety analysis and follows the guidelines and specifications included in the VDOT s Traffic Operations and 1 2 Safety Analysis Manual (TOSAM)P0F P and FHWA s Traffic Analysis Toolbox Volume IIIP1F P. The study area, assumptions, and methodology have been discussed and agreed upon with VDOT and FHWA staff as detailed in the following documents included in the Appendix: Appendix B: Framework Document for Traffic and Transportation Technical Report (dated April 4, 2017) Appendix C: Estimates of Ramp Volumes Technical Memorandum (dated February 7, 2017) The analysis was consistent with the previously completed Transform 66: Inside the Beltway (ITB) Eastbound Widening project and followed the same methodology and assumptions, as documented in the framework document for the ITB Eastbound Widening project Traffic and Transportation Technical Report (TaTTR), dated October 13, STUDY AREA FHWA guidelines indicate that the study area should include all roadways within the influence area of the project, including interchanges on either side of the project site. Figure 3.1 shows the project study area that includes the following: I-66 between I-495 and N Westmoreland Street I-66 and Route 7 interchange Route 7 between Pimmit Drive and Haycock Road Haycock Road between Route 7 and I-66 Intersections along Route 7 and Haycock Road including the following: 1. Route 7 and Pimmit Drive 2. Route 7 and Idylwood Road 3. Route 7 and eastbound I-66 off-ramp 4. Route 7 and Haycock Road 5. Haycock Road and Falls Church Drive 6. Haycock Road and Metro station entrance roadway 7. Falls Church Drive and UVA-VT Entrance/Park-and-Ride The project study area for this ramp modification analysis included the network developed for Transform 66 Inside the Beltway Eastbound Widening project and expanded to include additional intersections along Route 7 and Haycock Road. 1 Traffic Operations and Safety Analysis Manual (TOSAM) Version 1.0, VDOT Traffic Engineering Division, November Traffic Analysis Toolbox Volume III: Guidelines for Applying Traffic Microsimulation Software, Federal Highway Administration, June Transform Interstate 66 August

22 Route 7 Connector Ramp: Modified Interchange Modification Report Figure 3.1: Eastbound I-66 Exit 66 Route 7 Connector Ramp Traffic Study Area August 2017 Transform Interstate

23 Route 7 Connector Ramp: Modified Interchange Modification Report 3.2 ANALYSIS YEARS AND SCENARIOS This analysis years and scenarios were kept consistent with those in the I-66 ITB Eastbound Widening project TaTTR. The traffic analyses included assessments of typical weekday AM and PM peak-hour operations for the following years and scenarios: 1. Existing year Interim year 2025 No-Build 3. Interim year 2025 Build 4. Design year 2040 No-Build 5. Design year 2040 Build The No-Build conditions included all improvements projects planned and programmed within the study area. These improvements and their anticipated opening year are listed below: UTransform 66 Inside the Beltway Tolling, 2017U. Tolling on I-66 inside the Beltway will be implemented in the peak direction peak period (eastbound (EB) in the AM and westbound (WB) in the PM). Currently, the high-occupancy vehicle (HOV) restrictions are enforced on I-66 inside the Beltway between 6:30 9:00 a.m. (all EB travel lanes) and 4:00 6:30 p.m. (all WB travel lanes). The Inside the Beltway Tolling project will convert the existing HOV lanes to high-occupancy toll (HOT) lanes during an extended AM and PM peak period. The HOT restrictions will be 5:30 9:30 a.m. (all EB travel lanes) and 3:00 7:00 p.m. (all WB travel lanes) in the future years. UTransform 66 Inside the Beltway Eastbound Widening, 2019U. Widening on eastbound I-66 will add an additional lane and result in three travel lanes on eastbound I-66 between the Dulles Connector Road (Route 267) and Fairfax Drive near Ballston. URegional HOV/HOT requirements, 2020U. The vehicle occupancy requirement for all HOV/HOT facilities in the region will change from 2 or more (2+) to 3 or more (3+). The exemption for clean fuel and hybrid vehicles to use HOV lanes will also expire by UI-66 Spot 3 Improvements, 2020U. This project will construct an auxiliary lane connecting the on-ramp from Lee Highway (US 29) Exit 72 to the off-ramp to North Glebe Road (Route 120) Exit 71 on westbound I-66. UTransform 66 Outside the Beltway Express Lanes, 2022U. This project will improve I-66 outside the Beltway to add two Express Lanes in each direction, maintain three general purpose lanes in each direction, and provide travel choices such as express transit buses and park-and-ride facilities along the corridor. The Build conditions assumed the construction of the connector ramp described above, in addition to all improvements assumed in the No-Build condition. 3.3 DATA COLLECTION Data collection performed during March and April 2016 as part of the Transform 66 Inside the Beltway Eastbound Widening project was utilized in this study. Available traffic counts from VDOT in the form of turning movement counts at intersections were collected and used where available. Data collected previously included the following: Freeway counts: Three weekdays (Tuesday through Thursday) of continuous, directional, vehicle classification counts were conducted on freeway mainlines and at interchange ramps. Transform Interstate 66 August

24 Route 7 Connector Ramp: Modified Interchange Modification Report Intersection counts: For all intersections in the study area, 13-hour turning movement counts were conducted from 6:00 a.m. to 7:00 p.m. on weekdays. Traffic signal timing plans: The current signal timing plans at all signalized intersections within the study area were obtained from VDOT and local jurisdictions. Historical crash data: The most recent five-year crash data (2010 to 2015) within the study area were obtained from VDOT s crash database. StreetLightData has been extracted to estimate origin-destination (O-D) distribution patterns for the trips access to Metro station. Travel time runs were conducted for the path from eastbound I-66 to West Falls Church Metro station to validate the previously calibrated models. The travel time runs were conducted during weekday peak periods of 6:00 to 10:00 a.m. and 3:00 to 7:00 p.m. Consistent with the Eastbound Widening study, the AM and PM peak hours for analysis was set at 7:15 to 8:15 a.m. and 5:00 to 6:00 p.m. respectively. 3.4 TRAVEL DEMAND FORECASTING The proposed connector ramp will primarily divert traffic from the eastbound I-66 off-ramp to Route 7, the ramp terminus intersection, and the eastbound left turn at the intersection of Route 7 and Haycock Road. The connector ramp will also attract traffic from eastbound I-66 destined to the adjacent East Falls Church Metro station since it provides a direct path to the West Falls Church metro station. Therefore, the impacts to travel demand and patterns are minimal and cannot be captured by traditional demand model forecasts. The forecast volumes on the connector ramp and the study area were consequently derived from previous studies, specifically the Transform 66 Inside the Beltway Eastbound Widening project. Traffic diverted to the connector ramp from other routes was estimated using traffic patterns and origin-destination information provided by StreetLightData in the study area. A technical memorandum was submitted to VDOT on February 7, 2017, detailing the process and estimated traffic demand on the proposed connector ramp and approved by VDOT on February 15, This memorandum is included as Appendix C of the report. 3.5 TRAFFIC OPERATIONAL ANALYSIS VISSIM version 8.0 was used for a comprehensive network traffic analysis of the study area limits. As mentioned previously, the traffic and safety analysis for this project was built upon and consistent with the TaTTR for the I-66 ITB Eastbound Widening project. Therefore, calibrated VISSIM models developed previously for the I-66 ITB Eastbound Widening study were used in this study. No major model recalibration was performed. However, to ensure that the model accurately replicates the conditions in the field, the models were refined following TOSAM guidelines to validate against the field conditions, especially on Route 7 arterial and intersections on Route 7. Section in Chapter 5 presents the detailed model validation results based on field travel times. The following measures of effectiveness (MOEs) were used for the operational analysis of the roadway network under existing, future No-Build and Build conditions. 1. Simulated travel times from eastbound I-66 to the Metro station (seconds). 2. Simulated average control delay and congestion level for study intersections (seconds/vehicle, color-coded in similar fashion as the equivalent HCM delay-based LOS thresholds). 3. Simulated average and maximum queue lengths on eastbound I-66 off-ramp to Route 7 (feet). August 2017 Transform Interstate

25 Route 7 Connector Ramp: Modified Interchange Modification Report 4. Simulated average density and congestion level for the eastbound I-66 ramp segments at Route 7 (vehicles/lane/mile, color-coded similar to the equivalent density-based LOS Thresholds). Operational conditions of different facilities were categorized into four congestion levels by comparing the corresponding MOE values to the LOS thresholds established in the Highway Capacity Manual 2010 (HCM 2010). Namely, these MOEs are density for freeway segments and control delay for intersections. Table 3.1 presents the MOE thresholds and color scheme for congestion levels. Congestion Level Table 3.1: MOE Thresholds for Congestion Levels Equivalent HCM LOS Freeway Facility Weave, Merge, Basic Segment and Diverge Density (pc/mi/ln) Arterial Intersection Signalized Stop Control Control Control delay (sec/veh) Light Traffic A C <=26 <=28 <=35 <=25 Moderate Traffic D >26-35 >28-35 >35-55 >25-35 Heavily Congested Traffic E >35-45 >35-45 >55-80 >35-50 Severely Congested Traffic F >45 >45 >80 > SAFETY ANALYSIS 16TUsing data provided for the study area by VDOT, crash analysis was performed for existing conditions to reflect the most recent five-year period for which data is available. Crash analysis includes freeway mainline, interchange ramps, ramp terminus, and intersections on crossroads within the study area, a similar area as documented for traffic data collection. 16TA combination of qualitative and quantitative analyses was used to evaluate safety in the study area. Qualitative analyses included documenting existing crash frequencies, severity, and predominant crash types on the I-66 mainline, ramps, and intersections on the corridor and crossroads. Crash data was analyzed based on location, type, and severity to identify existing crash patterns and safety concerns in the study area. 16TQuantitative analyses, using AASHTO Highway Safety Manual (HSM) methodologies within the Enhanced Interchange Safety Analysis Tool (ISATe), was used to evaluate safety with the proposed connector ramp. The predictive crash methods detailed in the HSM was used to provide input into the roadway design process to evaluate safety for the various design options, including any recommended strategies to improve the safety performance of the proposed Build condition. 16TWhile the HSM models sufficiently fit the existing and proposed conditions of the freeway/interchange components of the study area to provide quantitative analysis, the HSM models are not an ideal fit for the arterial system given the complexity and would likely underestimate crash frequency for the surface streets within the study area limiting the benefit of quantitative analysis of the arterials. Therefore, the quantitative analysis using the ISATe and HSM methods was limited to the evaluation of the freeway exit and Ramps A and B for the No-Build and Build condition. Analysis of the arterial roadway system (Route 7, Haycock Road, Falls Church Drive) was limited to a qualitative evaluation of expected impacts. However, while evaluation of the arterials was qualitative, HSM concepts were used to provide insight into the expected benefit on the arterial system of the proposed condition. Transform Interstate 66 August

26 4. PREFERRED ALTERNATIVE Several preliminary alternatives were developed and evaluated for the proposed connector ramp from eastbound I-66 to access West Falls Church Metrorail station (herein referenced as Metro station ) and Northern Virginia Center UVA-VT Campus. This chapter provides an overview of the alternatives development, evaluation, and selection of the preferred concept for the proposed project. 4.1 NO-BUILD ALTERNATIVE The No-Build alternative, shown in Figure 4.1, retains the existing geometry and configuration with no connector ramp to access the Metro station. Motorists on I-66 wishing to access the Metro station will have to exit I-66 and turn right at the signal to southbound Route 7, weave across two travel lanes, and turn left at the Haycock Road intersection. Figure 4.1: Lane Configurations of No-Build Alternative 4.2 TRANSPORTATION SYSTEM MANAGEMENT OPTIONS Transportation System Management (TSM) focuses on improving the operational efficiency of transportation systems without major system improvements (such as adding lanes or new ramps). Freeway TSM strategies can include signing and pavement striping improvements, traffic surveillance and control equipment, incident management programs, HOV facilities, and ramp metering. Corridor and system-wide TSM strategies may incorporate improvements to mass transit service, multimodal facilities, and intelligent transportation systems (ITS). Transform Interstate 66 August

27 Route 7 Connector Ramp: Modified Interchange Modification Report On the I-66 corridor inside the Beltway, several TSM options are already in place including HOV restrictions, ramp metering, and proposed Express Lanes; however, these options will still not address the direct access and connectivity from eastbound I-66 to the Metro station. Therefore, TSM options alone will not satisfy the purpose and need of this project. 4.3 BUILD ALTERNATIVES The Build alternatives were developed based on reasonable design refinements that met the project s purpose and need. Through discussions with project stakeholders, VDOT initially identified a preliminary set of refinements and considered two alternatives for further analysis and evaluation. The Build alternatives include: Option 1 At-grade intersection connector: Adding through movement at eastbound I-66 off-ramp terminal intersection with Route 7. Three modifications of this option (1A, 1B, and 1C) were evaluated. Option 2 Direct connector ramp: Providing direct access from eastbound I-66 off-ramp. Two varieties of this option (2A and 2B) were evaluated. The sections below discuss the configuration of the Build alternatives Option 1: At-Grade Intersection Connector This option adds a through-lane adjacent to the existing two left-turn lanes at the eastbound approach of the eastbound I-66 off-ramp terminal intersection with Route 7. Thus, it provides a new at-grade intersection connector to the Metro station. It allows eastbound I-66 traffic to pass across Route 7 through a modified signalized intersection, continue along a modified northbound Route 7 to eastbound I-66 on-ramp, and provides access to the Metro station without getting on congested southbound Route 7. As a part of this modification, the eastbound I-66 on-ramp from northbound Route 7 would be realigned, creating a T intersection with the connector. This ramp modification is required primarily because the distance between the through-movement connector and the existing merging point of the two eastbound I-66 on-ramp branches is insufficient to safely accommodate the merge. A yield condition was proposed to control the northbound Route 7 ramp traffic. Vehicles traveling on this ramp would make a hard-right turn (instead of the current free-flow right turn) and would yield to the through movement traffic from the new connector before merging to the on-ramp to eastbound I-66. The development of Option 1 went through three iterations of refinements. The initial design of this option, noted as Option 1A, is to maintain the existing two-lane configuration of Ramp B as much as possible, as illustrated in Figure 4.2. The proposed through lane would be added only after the diverge point of the freeflow right-turn branch. However, due to the additional through traffic and limited storage space, the offramp operation of Option 1A would be very sensitive to the congestion level on Route 7. When Route 7 is heavily congested and the ramp terminal intersection is blocked with queuing vehicles, the off-ramp traffic would not be fully discharged every signal cycle. With this configuration, the residual queues are predicted to accumulate and extend as far as to the eastbound I-66 mainline. Figure 4.3 is a traffic simulation screenshot of the 2040 PM peak hour for Option 1A, which shows that the off-ramp queue spills back to the freeway mainline with the proposed lane configurations. August 2017 Transform Interstate

28 Route 7 Connector Ramp: Modified Interchange Modification Report Figure 4.2: Lane Configurations of Build Alternative Option 1A Two-Lane Ramp Figure 4.3: Simulated Option 1A Ramp Queuing Conditions To address the ramp queuing issue, Option 1A was modified to add one more lane, making it a total three lanes on Ramp B, to provide additional storage space to accommodate more queued vehicles. Figure 4.4 depicts the lane configurations of this modified concept, noted as Option 1B. The left two lanes will become left-turn lanes at the ramp terminal intersection. The rightmost lane would be a choice lane for through movement or free-flow right turn. In Option 1B, the off-ramp queues are not predicted to spill back to the freeway mainline. However, in the design year 2040, queues of through movement vehicles are predicted Transform Interstate 66 August

29 Route 7 Connector Ramp: Modified Interchange Modification Report to spill beyond the diverging point of the choice lane during the peak periods, therefore, blocking the rightturn movement. Figure 4.5 presents a simulation screenshot that demonstrates this condition. Figure 4.4: Lane Configurations of Build Alternative Option 1B Three-Lane Ramp Figure 4.5: Simulated Option 1B Ramp Queuing Conditions Option 1B was further refined to add a fourth lane on Ramp B. The lane configurations of this modification, noted as Option 1C, are illustrated in Figure 4.6. The existing eastbound I-66 off-ramp would be widened on the right side from the existing two lanes to four lanes. The rightmost lane would be a dedicated free- August 2017 Transform Interstate

30 Route 7 Connector Ramp: Modified Interchange Modification Report flow right-turn lane to southbound Route 7. The second right lane would be a through-movement-only lane, and the left two lanes would still be dedicated left-turn lanes. Based on preliminary simulation analysis, Option 1C will resolve most queuing issues in Options 1A and 1B and provide much cleaner operations on the eastbound off-ramp; therefore, it was selected as the final concept of Option 1 for further considerations in detailed alternative comparisons. Figure 4.6: Lane Configurations of Build Alternative Option 1C Four-Lane Ramp Option 2: Direction Connector Ramp This option modifies the eastbound I-66 off-ramp at Exit 66 to include two lanes instead of one lane as in the existing conditions. A new spur is proposed that connects the I-66 eastbound off-ramp to the existing Route 7 southbound ramp that connects to the I-66 eastbound connector-distributor (C-D) road. This option would allow vehicular traffic trying to access the Metro station to avoid getting on to Route 7. Therefore, it would reduce the delay at the Route 7 and Haycock Road intersection. Because of this connection, the merge area for the new access ramp and on-ramp from southbound Route 7 would be widened from one lane to two lanes. Two variations of this option, Options 2A and 2B, were developed to evaluate the most effective design that provides operational and safety benefits. The lane configurations are illustrated in Figure 4.7 and Figure 4.8, respectively. Transform Interstate 66 August

31 Route 7 Connector Ramp: Modified Interchange Modification Report Figure 4.7: Lane Configurations of Build Alternative Option 2A Choice Lane Figure 4.8: Lane Configurations of Build Alternative Option 2B Dedicated Lane August 2017 Transform Interstate

32 Route 7 Connector Ramp: Modified Interchange Modification Report Option 2A has two lanes instead of the current one lane at the eastbound off-ramp. The left lane is a choice lane. Traffic can choose either to go to the new connector ramp and merge with Ramp A or continue to Ramp B as in the existing conditions. Option 2B also has two lanes at the eastbound off-ramp. Then it splits into two spurs. The left lane diverts to the proposed connector ramp, and the right lane ties into the existing Ramp B with a second lane opening on the left side. After discussion with VDOT Location and Design Division and Traffic Engineering Division, Option 2B was considered as the alternative for further analysis because it provides more balanced benefits considering geometric design, signage, and operational and safety benefits. 4.4 ALTERNATIVE EVALUATIONS Preliminary Operational Analysis A preliminary traffic operational analysis was performed for the two alternatives using the computer microsimulation program VISSIM (version 8). As part of the I-66 Eastbound Widening project, a comprehensive set of VISSIM microsimulation models were developed that encompass the entire I-66 eastbound widening study area from I-495 to Lee Highway (Spout Run Parkway). Different alternatives were tested by modifying the VISSIM microsimulation models. The PM peak hour under the 2025 and 2040 Build scenarios was used to evaluate alternatives since they represented the worst-case scenario for the eastbound I-66 off-ramp and Route 7 intersections in the study area. The following measures of effectiveness (MOEs) were used to evaluate traffic operational performance of the alternatives for the 2025 and 2040 PM scenarios. Ramp operations (densities and levels of congestion) Arterial intersection operations (delays and levels of congestion) Queue lengths at the eastbound I-66 off-ramp to Route 7 Travel times from eastbound I-66 inside the Beltway to the Metro station Ramp Operations Table 4.1 presents the operational analysis results on eastbound I-66 ramps at the Route 7 interchange during 2025 and 2040 PM peak hour conditions. Table 4.1: Eastbound I-66 Ramps at Route 7 Traffic Operations, 2025 and 2040 PM Peak Hours 2025 PM Density (pc/ln/mi) 2040 PM Density (pc/ln/mi) Ramp Segment No-Build Option Option No-Build Option Option 1C 2B 1C 2B EB I-66 Off-Ramp to Route 7 (Ramp B) EB I-66 Off-Ramp to SB Route 7 (Right-Turn Branch) At-Grade Intersection Connector (Option 1) NA 2.0 NA NA 2.3 NA New Connector Ramp (Option 2) NA NA 8.8 NA NA 6.5 EB I-66 Collector-Distributor Road Weaving Segment Off-Ramp to West Falls Church Metro Severely congested traffic Heavy congested traffic Moderate traffic Light traffic Transform Interstate 66 August

33 Route 7 Connector Ramp: Modified Interchange Modification Report Under both options, the operations on Route 7 interchange ramps are anticipated to be improved. All the different ramp segments would operate under light or moderate traffic conditions. Both options will divert traffic to go through the weaving segment on the collector-distributor (C-D) road, but the increased volumes are not significant enough to degrade the operational conditions. Simulation results show that, under both options, this segment would operate under light traffic conditions with slightly higher vehicle densities, but with no noticeable operational issues. Arterial Intersection Operations Table 4.2 and Table 4.3 summarize 2025 and 2040 PM peak-hour intersection delays and congestion levels at the study intersections as compared to the corresponding No-Build scenario. Table 4.2: Intersection Delays and Levels of Congestion, 2025 PM Peak Hour Intersection 2025 PM Intersection Delay (seconds/vehicle) No-Build Option 1C Option 2B Leesburg Pike/Pimmit Dr Leesburg Pike/Idylwood Road EB I-66 Off-Ramp/Leesburg Pike (Route 7) Leesburg Pike (Route 7)/Haycock Road/Shreve Rd Haycock Rd/Falls Church Dr Haycock Rd/Park Ride Falls Church Dr/Park Ride Falls Church Dr/Metro Station Park Ride/Metro Station Severely congested traffic Heavy congested traffic Moderate traffic Light traffic Table 4.3: Intersection Delays and Levels of Congestion, 2040 PM Peak Hour Intersection 2040 PM Intersection Delay (seconds/vehicle) No-Build Option 1C Option 2B Leesburg Pike/Pimmit Dr Leesburg Pike/Idylwood Road EB I-66 Off-Ramp/Leesburg Pike (Route 7) Leesburg Pike (Route 7)/Haycock Road/Shreve Rd Haycock Rd/Falls Church Dr Haycock Rd/Park Ride Falls Church Dr/Park Ride Falls Church Dr/Metro Station Park Ride/Metro Station Severely congested traffic Heavy congested traffic Moderate traffic Light traffic The results indicate that both Build options would improve the overall arterial intersections performance, especially at the two most-affected intersections: eastbound I-66 off-ramp and Route 7 and Haycock Road and Route 7. The operations analysis results in 2025 are similar to the 2040 results. With Option 1C, the vehicles accessing the Metro station would go through at the intersection. With Option 2B, the vehicles August 2017 Transform Interstate

34 Route 7 Connector Ramp: Modified Interchange Modification Report would have a direct access ramp to reach the Metro station and therefore would not experience any intersection delays. The intersection operations in Option 2B are slightly better than in Option 1C in both years. Eastbound Off-Ramp Queuing Conditions Table 4.4 summarizes the average and maximum queue lengths at the eastbound I-66 off-ramp approach to the intersection at Route 7 for the 2025 and 2040 PM scenarios. The available storage space is about 1,000 feet from the stop bar of the eastbound approach at the ramp terminal intersection to the diverging gore point of the eastbound off-ramp. Simulation results show that both options would significantly reduce average and maximum queue lengths at the intersection eastbound approach. Under the No-Build scenarios, analysis indicates that the maximum queues would spill back to the freeway mainline. This condition would be eliminated under both Build options. Furthermore, Option 2B would operate with shorter queues than Option 1C. Table 4.4: Queue Lengths at the Eastbound I-66 Off-Ramp to Route 7, 2025 and 2040 PM Peak Hours Scenarios 2025 PM 2040 PM Ave. Queue (ft) Max. Queue (ft) Ave. Queue (ft) Max. Queue (ft) No-Build Option 1C Option 2B * The shaded cell indicates the queue spills back to freeway mainline. Travel Time Figure 4.9 shows the travel time results for vehicles from eastbound I-66 to the Metro station for different scenarios during the 2025 and 2040 PM peak hours. The travel time results show that both Build options would reduce travel times by percent in the 2025 and 2040 PM scenarios. Option 2B would result in lower travel times than Option 1C, because vehicles do not have to travel through the signalized intersection in Option 2B. Figure 4.9: Eastbound I-66 Travel Times to the Metro Station, 2025 and 2040 PM Peak Hours Transform Interstate 66 August

35 Route 7 Connector Ramp: Modified Interchange Modification Report Overall Traffic Operations Comparison In summary, both Options 1C and 2B improve the traffic operational conditions on eastbound ramps as well as at arterial intersections, and they both would significantly reduce travel times to the Metro station, as compared to the No-Build alternative. Between these two options, Option 2B has an edge over Option 1C, as it offers improved operations by providing a direct connector ramp to avoid the already-congested Route 7 intersections Preliminary Safety Analysis A combination of qualitative and quantitative safety analyses was performed to evaluate and compare the safety impacts for both Build options. Freeway and Ramp Safety A comparison of the predicted safety impacts to the freeway and ramps indicates minimal impact on the freeway and an expected 7 percent and 9 percent higher average annual crash frequency for the ramps in Options 1C and 2B Build conditions, respectively. However, based on the review of existing crash data, there were very few crashes on the ramps, and the expected average annual crash frequency was lower than the predicted result for the existing conditions indicating the ramp is currently performing better than other comparable sites. Overall, the impact is predicted to be similar and minor for the two options; the calculations indicate increases will be primarily limited to low severity injury and property damage only. C-D Road Segment Safety Table 4.5 lists the predicted crashes under different scenarios in 2025 and Both Build options are expected to increase the annual crash frequency by approximately 11 percent in both 2025 and The increase in annual crash frequency is expected due to the increase in AADT that will occur by traffic redirected with the proposed ramp connector. The expected increase in crash frequency would be similar between the two Build options because both proposed ramp connectors ultimately redirect traffic to the same location, and at the C-D road, that redirection is complete. Based on the most recent five-year crash history, there was only one crash between 2012 and 2016; therefore, the increase in predicted number of annual crashes on this segment is not significant, 0.07 predicated crashes per year. Table 4.5: Comparisons of Predicted Crashes on C-D Road Segment Scenarios 2025 Annual Safety (Number of predicted crashes per year) 2040 Annual Safety (Number of predicted crashes per year) Predicted No-Build Predicted Option 1C Build Predicted Option 2B Build Difference between No-Build and Option 1C Difference between No-Build and Option 2B August 2017 Transform Interstate

36 Route 7 Connector Ramp: Modified Interchange Modification Report Local Arterial Safety The most recent five-year ( ) crash data identifies the Route 7 corridor and the intersection of Route 7 and Haycock Road as priority crash locations within the study area. The predominant crash types at these locations were rear-end and angle collisions. While detailed quantitative analyses were not performed, the evaluation of the two affected intersections (ramp terminus and Route 7/Haycock Road) was performed to determine the impact on crash frequency because of the change in traffic volumes. The evaluation of the local system was limited to these two intersections; therefore, the anticipated benefit would likely be greater for both if considering the entire section of roadway along the current travel path of the diverted vehicles. The resulting analysis indicates a reduction in traffic volumes would produce an approximate 4 percent reduction in average annual crashes at the Route 7 and Haycock Road intersection for both Options 1C and 2B Build conditions. In addition, both options will reduce the weaving volumes on southbound Route 7 between the off-ramp merging point and Haycock Road intersection, which would improve traffic flow and benefit safety on this segment. Because Option 1C will introduce a new through movement at the off-ramp terminal intersection and divert additional traffic across Route 7, however, it is predicted that there would be at least 19 percent increase in crashes at this intersection. In the recent five years, 16 crashes occurred here. Therefore, the crash reduction at Haycock Road intersection in Option 1C would likely be offset by the increase at the off-ramp terminal intersection. Overall Safety Comparisons A comparison of Option 1C to Option 2B indicates that the impacts to the ramps within the interchange area are generally similar, yet a difference is expected on the arterial. An overall improvement is likely in Option 2B whereas there would not be as much of an overall improvement for Option 1C, and potentially a negative impact because of redirecting traffic through the eastbound ramp intersection. The expected decrease at the Route 7 and Haycock Road intersection common to both Options 1C and 2B would be offset by an increase at the eastbound I-66 ramp to Route 7 intersection in Option 1C; therefore, by this reasoning, Option 2B is preferable to Option 1C from the safety perspective. In conclusion, the Option 2B Build condition is predicted to have minimal negative safety impacts within the study area and fewer impacts than Option 1C. The expected increase on the ramps is less than the anticipated reduction along the arterials. Where average annual crash frequency is expected to increase, impact is expected to be limited to an increase in lower severity and property damage only crashes. Additionally, given that the estimates of the impact to arterials are based on select intersections using volume only, Option 2B is likely to result in even fewer overall crashes than estimated on the arterial Compliance with Design Criteria Based on conceptual-level design, there is one design exception (DE) and three design waivers (DW s) identified in Option 1C, no DE and three DW s in Option 2. Table 4.6 and Table 4.7 present the descriptions of the potential design exceptions and waivers for each option respectively. Transform Interstate 66 August

37 Route 7 Connector Ramp: Modified Interchange Modification Report Table 4.6: Potential Design Exceptions and Waivers in Option 1C DE or DW DE 1 DW 2 DW 3 DW 4 No Item Location Design Feature Proposed Design Substandard superelevation transition length Substandard ramp gore design BPPS-1 for existing bridge piers Substandard existing impact attenuator Along Ramp-H Mod/Ramp E merge Ramp-H Mod/Ramp- B Free-flow on Route 7 SB Route 7 NB/under I- 66 Mainline bridge NB median barrier Route 7/ under I-66 Mainline bridge Superelevation Gore Design BPPS-1 Impact Attenuator Inadequate tangent length (30 feet) Non-standard Taper & Recovery Area Modified BPPS-1 needs VDOT review and approval. Modified attenuator needs VDOT review and approval. Min AASHTO (DE) and VDOT (DW) Requirements 100 feet Min Recommended by AASHTO and VDOT Road Design Manual VDOT Road Design Manual VDOT Manual of the Structure and Bridge Part 3 VDOT Manual of the Structure and Bridge Part 3 Purpose & Need for Exception Constrained by the existing site condition. Constrained by the existing the site condition. Existing BPPS is outside of the work limit of this option, therefore not considered for replacement. Existing attenuator is outside of the work limit of this option, therefore not considered for replacement. Table 4.7: Potential Design Exceptions and Waivers in Option 2B (Preferred Alternative) DE or DW DW 1 DW 2 DW 3 No Item Location Design Feature Proposed Design Short distance between two consecutive gores along Ramp B (at EB I-66 and Ramp W) Substandard ramp gore design BPPS-1 for new bridge piers Ramp B (Sta to Sta ) Ramp B at EB I-66 and Ramp W Route 7 under Ramp A bridge Gore Spacing Gore Design BPPS feet Non-standard Taper & Recovery Area Modified BPPS-1 needs VDOT review and approval. Min AASHTO (DE) and VDOT (DW) Requirements 600 feet Min Recommended (AASHTO Figure 10-68) VDOT Road Design Manual VDOT Manual of the Structure and Bridge Part 3 Purpose & Need for Exception Constrained by the existing interchange configuration and bridge infrastructures. Constrained by the existing interchange configuration and bridge infrastructures. Constrained by the existing intersection configuration. August 2017 Transform Interstate

38 Route 7 Connector Ramp: Modified Interchange Modification Report Preliminary Cost Estimates A preliminary assessment of construction costs was calculated based on the conceptual-level design of both options for comparison purposes. Option 1C involves additional pavement at the eastbound off-ramp and the approach to the intersection, modifications to the signal infrastructure, construction of the spur from the intersection to the on-ramp from northbound Route 7 to eastbound I-66, and the modified on-ramp alignment. The preliminary cost estimate of this option is about $2.3 million. Option 2B involves modifications to the off-ramp from eastbound I-66 to Route 7 and the bridge from southbound Route 7 to eastbound I-66, with no changes to the signalized intersection. The preliminary cost estimate of this option is about $3 million Other Impacts Other impacts that were reviewed include right-of-way, utility impacts, environmental, and maintenance of traffic (MOT) during construction. A qualitative assessment of these impacts was made for comparing the two options. Right-of-Way (ROW) The existing ROW is sufficient to accommodate both Option 1C and Option 2B. No additional ROW acquisition or modification of the Limited Access lines is required. Utility Utility impacts are minimal for Option 2B whereas some of the existing utilities at the intersection of eastbound I-66 off-ramp and Route 7 may require relocation for Option 1C. Environmental Both options are anticipated to have minimal impacts to the local environment. Maintenance of Traffic (MOT) Option 1C involves in the roadway construction and utility relocation along the off-ramp terminus as well as Route 7. Due to consistent heavy traffic at both facilities, the MOT for this option is a challenge. But the ramp widening can be constructed in two phases with shoulder closure to stay away from Route 7 mainline. Utility relocation is mainly for the traffic signal, communication and power service relocation, majority of which is offsite and away from Route 7 mainline. The construction of connector ramp in Option 2B will mostly occur to the areas between I-66 ramps. However, Option 2 also include the Ramp A bridge widening, which will require MOT on both freeway ramp and Route 7. There will be minimal utility relocation needed in this option. In all, the requirements to maintain traffic during Option 2B construction would be more challenging than Option 1C. Transform Interstate 66 August

39 Route 7 Connector Ramp: Modified Interchange Modification Report Evaluation Matrix Table 4.8 presents a comparison matrix of the Build options based on the above evaluation results. In consideration of the impacts of both options presented above, as well as discussions with localities and other stakeholders, Option 2B is presented as the Preferred Build Alternative. Traffic Operations Safety Legend: Criteria Table 4.8: Evaluation Matrix for Build Options No-Build Build Option 1C: At-Grade Intersection Connector Build Option 2B: Connector Ramp Travel Time to Metro Station Eastbound I-66 Ramp Operations C-D Weaving Operations Off-Ramp Queuing Conditions Arterial Operations Ramp and C-D Road Safety Ramp Terminal Intersection Southbound Route 7 and Haycock Road Intersection Compliance with Design Criteria 1 DE, 3 DW 3 DW Conceptual Cost Estimate $2.3 million $3 million Maintenance of Traffic Right-of-Way Impacts Environmental Impacts Utility Impacts Supporting Purpose and Need - Accessibility to Metro Station Poor Unfavorable Neutral Favorable Excellent 4.5 ROADWAY GEOMETRY OF THE PREFERRED ALTERNATIVE Conceptual Roadway Geometry Design The conceptual layout of the Preferred Alternative is shown in Figure 4.10 and Figure For Ramp A, both the existing posted speed and design speed are 30 miles per hour. For Ramp B, both the existing posted speed and design speed are 35 miles per hour. For the proposed connector ramp, the design speed is 30 miles per hour. August 2017 Transform Interstate

40 Route 7 Connector Ramp: Modified Interchange Modification Report Figure 4.10: Preliminary Conceptual Plan of the Preferred Alternative (Sheet 1 of 2) Transform Interstate 66 August

41 Route 7 Connector Ramp: Modified Interchange Modification Report Figure 4.11: Preliminary Conceptual Plan of the Preferred Alternative (Sheet 2 of 2) August 2017 Transform Interstate

42 Route 7 Connector Ramp: Modified Interchange Modification Report Design Exceptions and Design Waivers Table 4.7 shows the design exceptions and waivers incorporated in the Preferred Alternative. In all, there are no design exceptions (DE) and three design waivers (DW) in the Preferred Alternative based on the preliminary geometric design Conceptual Signing Plan A preliminary signage plan was prepared for the Preferred Alternative and is shown in Figure 4.12 and Figure The layout was developed to comply with current MUTCD (2009 Edition) and VDOT Supplement (2011 Edition) requirements for all roadways. The layout focuses on large-scale guide signs needed for motorist orientation and directional aid but does not identify regulatory and warning signs that may needed. The signing plan is subject to refinement and further detailing during final design. Transform Interstate 66 August

43 Route 7 Connector Ramp: Modified Interchange Modification Report Figure 4.12: Conceptual Signing Plan (Sheet 1 of 2) August 2017 Transform Interstate

44 Route 7 Connector Ramp: Modified Interchange Modification Report Figure 4.13: Conceptual Signing Plan (Sheet 2 of 2) Transform Interstate 66 August

45 5. EXISTING TRAFFIC CONDITIONS Existing traffic volumes, patterns, and operational conditions on the I-66 inside the Beltway corridor and Route 7 have been extensively discussed in the Traffic and Transportation Technical Report (TaTTR) for Transform 66: Inside the Beltway, Eastbound Widening Environmental Assessment (EA). The proposed connector ramp will primarily provide a direct access to West Falls Church Metro station from eastbound I-66 and divert traffic from the eastbound I-66 off-ramp to Route 7 (Exit 66), the ramp terminus intersection, and the eastbound left-turn movement at the intersection of Route 7 and Haycock Road. This chapter focuses on the existing traffic operational conditions at the arterial intersections and the I-66/Route 7 interchange and ramps. 5.1 EXISTING TRAFFIC VOLUMES Existing Peak-Hour Traffic Volumes Transform 66: Inside the Beltway, Eastbound Widening EA TaTTR provides 2016 traffic volumes on the I-66 mainlines, ramps for the I-66/Route 7 interchange, and turning movements of ramp terminus and adjacent intersections along Route 7 including: Route 7 and eastbound I-66 off-ramp, Route 7 and Haycock Road, Route 7 and Pimmit Drive, and Route 7 and Idylwood Road. Available turning movement counts and traffic counts sourced from VDOT were utilized to develop balanced 2016 volumes for the rest of the intersections in the study area including: Haycock Road and Falls Church Drive Haycock Road and Park and Ride Road. Figure 5.1 and Figure 5.2 present the existing year (2016) traffic volumes for freeway mainlines and ramps and intersection turning movements along arterials within the study area during AM and PM peak hours. Transform Interstate 66 August

46 Route 7 Connector Ramp: Modified Interchange Modification Report Figure 5.1: Existing Year (2016) Peak Hour Traffic Freeway and Ramp Volumes August 2017 Transform Interstate

47 Route 7 Connector Ramp: Modified Interchange Modification Report Figure 5.2: Existing Year (2016) Peak Hour Traffic Arterial Intersection Turning Volumes Transform Interstate 66 August

48 Route 7 Connector Ramp: Modified Interchange Modification Report Traffic Estimation on the Proposed Connector Ramp As mentioned previously, the proposed connector ramp diverts traffic from the eastbound I-66 off-ramp to Route 7, the ramp terminus intersection, and the eastbound left turn at the intersection of Route 7 and Haycock Road. To estimate the level of diversion, an understanding of trip origin and destination patterns in the study area for the traffic exiting I-66 to southbound Route 7 is essential. State-of-the-art data analytics provided by StreetLightData was used to assess the traffic patterns in the study area and estimate the volume that will potentially divert to the new connector ramp. A detailed technical memorandum was developed on February 7, 2017, to document the process and forecasted traffic volumes on the proposed ramp. This memorandum is included as Appendix C to the report. Table 5.1 summarizes the traffic volumes from the eastbound I-66 off-ramp at Route 7 that turn left at the Route 7 and Haycock Road intersection. Time Period Table 5.1: Traffic from Eastbound I-66 to West Falls Church Metro/Haycock Road SB Route 7 Left-Turn Volumes at Haycock Road Percentage from I-66 Ramp Turning Left at Haycock Road Volume from I-66 Ramp Turning Left at Haycock Road AM Peak Hour % 110 PM Peak Hour % 290 Daily Total % 2060 Apart from the above, it is estimated that an additional 40 vehicles are anticipated to be diverted to the connector ramp from traffic headed to the East Falls Church Metro station. Therefore, the total daily traffic that is expected to divert to the proposed connector ramp under existing traffic conditions is about 2,100 vehicles. 5.2 EXISTING TRAFFIC OPERATIONS AND CONGESTION LEVELS Baseline VISSIM Model Development and Validation VISSIM version 8 was used for the comprehensive traffic analysis for the network study area limits. The traffic analysis models for this project were built upon the calibrated VISSIM models developed for the TaTTR by adding additional network segments and intersections on Haycock Road and the West Falls Church Metro entry and exit roadways. A re-calibration of the network was not performed because a major portion of the network in the study area was already calibrated during the previous study. However, a comprehensive validation of the models was performed following VDOT s TOSAM guidelines to ensure that the models replicated field conditions in the study area. The following metrics were used for validating the models. Travel times from eastbound I-66 to the West Falls Church Metro station were used to validate the model results in the study area. Traffic volumes along Haycock Road intersections were adjusted to meet field observations. VISSIM simulation animations were inspected to validate queuing conditions at the Route 7 and Haycock Road intersection to ensure that the model replicated field observations. August 2017 Transform Interstate

49 Route 7 Connector Ramp: Modified Interchange Modification Report Traffic Operations Results Ramp Operations Table 5.2 and Table 5.3 show the operational analysis results on eastbound I-66 ramps at the Route 7 interchange for the 2016 AM peak hour and PM peak hour conditions. It can be seen from the results that the model throughputs are within 6 percent of the demand at the ramp segments of eastbound I-66 in the study area. Table 5.2: Eastbound I-66 Ramps at Route 7 Traffic Operations 2016 AM Peak Hour 2016 AM Peak Hour Location Demand Throughput Speed Density Δ% (veh/hr) (veh/hr) (mph) (pc/ln/mi) EB I-66 Off-Ramp to Route 7 (Ramp B) % EB I-66 Off-Ramp to SB Route 7 (Right-Turn Branch) % On-Ramp from SB Route 7 to EB I-66 (Ramp A) % Collector-Distributor Road Weaving Segment % Off-Ramp to West Falls Church Metro Station % Severely congested traffic Heavy congested traffic Moderate traffic Light traffic Table 5.3: Eastbound I-66 Ramps at Route 7 Traffic Operations 2016 PM Peak Hours 2016 PM Peak Hour Location Demand Throughput Speed Density Δ% (veh/hr) (veh/hr) (mph) (pc/ln/mi) EB I-66 Off-Ramp to Route 7 (Ramp B) 1,255 1,221 3% EB I-66 Off-Ramp to SB Route 7 (Right-Turn Branch) % On-Ramp from SB Route 7 to EB I-66 (Ramp A) % Collector-Distributor Road Weaving Segment % Off-Ramp to West Falls Church Metro Station % Severely congested traffic Heavy congested traffic Moderate traffic Light traffic The existing congestion maps for freeways and ramps in the study area during AM and PM peak hours are shown in Figure 5.5 and Figure 5.6 respectively. During the AM peak hour in the HOV restricted period, all segments on eastbound I-66 in the study area are operating with little or no congestion. During the PM peak hour, due to the heavy demand on eastbound I-66 and the congestion resulting from the merge segment from Dulles Connector Road with eastbound I-66, there is significant congestion and spill back up to the Route 7 interchange. Congestion on the Route 7 arterial also causes queuing and congestion on the eastbound I-66 off-ramp at Route 7. Transform Interstate 66 August

50 Route 7 Connector Ramp: Modified Interchange Modification Report Figure 5.3: Freeway and Ramp Congestion Map 2016 AM Peak Hour Figure 5.4: Freeway and Ramp Congestion Map 2016 PM Peak Hour August 2017 Transform Interstate

51 Route 7 Connector Ramp: Modified Interchange Modification Report Travel Time Table 5.4 and Table 5.5 show the average travel times from eastbound I-66 to West Falls Church Metro entrance from 2016 AM and PM VISSIM model outputs against field-measured travel times. The differences between the simulated travel times and field measurements are -12 and 0 percent in the AM and PM peak hours respectively. On most segment, the differences are within 30 percent threshold as defined in VDOT s TOSAM. The only two exceptions are two very short segments, and the absolute differences in travel times are relatively small, less than 30 seconds. As mentioned in Chapter 3, the VISSIM models used for this study were built upon the calibrated models developed previously for the I-66 ITB Eastbound Widening study. The models had been calibrated on all the freeway segments and interchange ramps. With the additional validation on arterial travel times, it can be concluded that the existing condition models were calibrated for the study area per VDOT s TOSAM criteria. Table 5.4: Comparison of 2016 Model Travel Times with Field Travel Times AM Peak Hour From Merge point of northbound I- 495 ramp with eastbound I-66 Travel Time Segment To Field Measured (min) AM Peak Hour Model Output (min) (min) (%) Barbour Road Bridge % Barbour Road Bridge Merge point of eastbound I-66 ramp with southbound Route % Merge point of eastbound I-66 Route 7/Haycock Road ramp with southbound Route 7 intersection % Route 7/Haycock Road Haycock Road/Falls Church intersection Drive intersection % Haycock Road/Falls Church West Falls Church Metro Drive intersection Garage entrance % Total % Table 5.5: Comparison of 2016 Model Travel Times with Field Travel Times PM Peak Hour From Merge point of northbound I- 495 ramp with eastbound I-66 Travel Time Segment To Field Measured (min) PM Peak Hour Model Output (min) (min) (%) Barbour Road Bridge % Barbour Road Bridge Merge point of eastbound I-66 ramp with southbound Route % Merge point of eastbound I-66 Route 7/Haycock Road ramp with southbound Route 7 intersection % Route 7/Haycock Road Haycock Road/Falls Church intersection Drive intersection % Haycock Road/Falls Church West Falls Church Metro Drive intersection Garage entrance % Total % Transform Interstate 66 August

52 Route 7 Connector Ramp: Modified Interchange Modification Report Figure 5.5 and Figure 5.6 compare the cumulative travel time trajectories between model and field conditions from I-495 to West Falls Church Metro Parking during the 2016 AM and PM Peak Hours. Travel Time (min) Travel Time - I-495 to West Falls Church Metro Parking - AM (7:15-8:15) Metro Station Haycock Falls Church Dr Route7@Haycock Rd Merge of Route 7 I-495 Barbour Rd Bridge Distance (mile) VISSIM Travel Time Field Travel Time Figure 5.5: Travel Time Trajectories Comparison 2016 AM Peak Hour Travel Time (min) Travel Time - I-495 to West Falls Church Metro Parking - PM (5:00-6:00) Metro Station Haycock Falls Church Dr Route7@Haycock Rd Merge of Route 7 I-495 Barbour Rd Bridge Distance (mile) VISSIM Travel Time Field Travel Time Figure 5.6: Travel Time Trajectory Comparison 2016 PM Peak Hour The figures above show that the microsimulation model results match with field-observed travel times for the travel time segment during the peak hours. For both the peak hours, congested conditions at the Route 7 and Haycock Road resulted in increased travel times for vehicles from eastbound I-66 to West Falls Church Metro station. The travel time for the segment from the eastbound I-66 off-ramp to the Route 7 and Haycock Road intersection increases from about 2 minutes in the AM peak hour to almost 4 minutes in the PM peak hour. August 2017 Transform Interstate

53 Route 7 Connector Ramp: Modified Interchange Modification Report Arterial Intersection Operations Table 5.6 summarizes arterial traffic operational results as measured by the average vehicle delays and level of congestion for all intersections within the study area during existing AM and PM peak hours. Detailed results on intersection operations such as movement-level delays, throughputs, and queues are included in Appendix D. Table 5.6: Intersection Delay and Congestion Level during Existing AM and PM Peak Hour 2016 AM Peak Hour 2016 PM Peak Hour Intersection Average Delay (sec/veh) Average Delay (sec/veh) Leesburg Pike(Route 7)/Pimmit Drive Leesburg Pike (Route 7)/Idylwood Road EB I-66 Off-Ramp/Leesburg Pike (Route 7) Leesburg Pike (Route 7)/Haycock Road/Shreve Road Haycock Rd/Falls Church Drive Haycock Rd/Park and Ride Road Falls Church Drive/Park and Ride Road Falls Church Drive/Metro Station Park and Ride Road/Metro Station Severely congested traffic Heavy congested traffic Moderate traffic Light traffic During the existing AM peak hour, most of the intersections operate with little or no congestion. The intersection of Route 7 and Haycock Road operates with moderate congestion whereas the intersection of Route 7 at Idylwood Road is severely congested. During the existing PM peak hour, all intersections on Route 7 within the study area including Haycock Road are operating at severe congested conditions. All intersections east of Haycock Road are operating with little or no congestion. Transform Interstate 66 August

54 6. ASSESSMENT OF FUTURE TRAFFIC CONDITIONS This chapter summarizes the traffic analysis of two future scenarios: interim year (2025) and design year (2040). The traffic analysis included the assessment of typical weekday AM and PM peak-hour operations. 6.1 OVERVIEW OF NO-BUILD AND BUILD CONDITIONS No-Build Conditions The assumption for future year No-Build conditions includes all the improvements included in the Transform 66 Inside the Beltway Eastbound Widening project TaTTR including the following: 1. Implementation of tolling on I-66 inside the Beltway in the peak direction during the peak periods by Implementation of tolling on I-66 inside the Beltway in both directions during the peak periods by Implementation of Express Lanes on I-66 outside the Beltway by Widening of eastbound I-66 between Dulles Connector Road (Route 267) and Fairfax Drive near Ballston, and improvements to eastbound I-66 exit ramps at Exit 69 and Exit 71 by Build Conditions The 2025 and 2040 Build conditions include all improvements assumed above. They will also include the proposed connector ramp on the eastbound I-66 off-ramp to Route 7 at Exit 66. For the 2040 conditions, it is recommended that the intersection of Falls Church Drive Park and Ride Road should be signalized based on the traffic forecasts and predicted operational conditions. This intersection is currently controlled under all-way stop signs. The signalization is needed after 2025 when the warrants are met to reduce queuing and congestion at this intersection that may spill back to the eastbound I-66 ramp segments during the PM peak hour INTERIM YEAR ANALYSIS Traffic Volumes Figure 6.1 and Figure 6.2 show the AM and PM peak-hour traffic demand volumes on freeway mainlines and local intersections within the study area for the 2025 No-Build and Build scenarios. The volumes for the intersections on Route 7 were adopted from the TaTTR. The volumes for the intersections on Haycock Road were estimated based on growth factors developed for Route 7/Haycock Road intersection and balanced with the rest of the network intersections. Transform Interstate 66 August

55 Route 7 Connector Ramp: Modified Interchange Modification Report Figure 6.1: Interim Year (2025) Peak-Hour Traffic Demand Volumes on Freeway and Ramp August 2017 Transform Interstate

56 Route 7 Connector Ramp: Modified Interchange Modification Report Figure 6.2: Interim Year (2025) Peak-Hour Traffic Demand at Intersections on Route 7 Transform Interstate 66 August

57 Route 7 Connector Ramp: Modified Interchange Modification Report Table 6.1 shows the estimated volumes for the proposed connector ramp based on the methodology described in Appendix D. As mentioned previously, the connector ramp will divert traffic that currently exits I-66 off-ramp to Route 7, merges with southbound Route 7, and turns left at the Route 7/Haycock Road intersection. Table 6.1: Peak-Hour Traffic Volumes on the Proposed Connector Ramp Interim Year 2025 Location AM Peak Hour Volumes PM Peak Hour Volumes 2025 No-Build 2025 Build 2025 No-Build 2025 Build Proposed Connector Ramp N/A 140 N/A 301 Eastbound left turn at the Route 7 and Haycock Road Intersection No-Build vs. Build Operations Freeway and Ramp Operations Table 6.2 and Table 6.3 summarize the traffic operational conditions of the eastbound I-66 ramp segments near Route 7 interchange during the AM peak hour for 2025 No-Build and Build scenarios respectively. Table 6.2: Eastbound I-66 Ramps at Route 7 Traffic Operations 2025 No-Build AM Peak Hour 2025 No-Build AM Location Demand Throughput Speed Density Δ% (veh/hr) (veh/hr) (mph) (pc/ln/mi) EB I-66 Off-Ramp to Route 7 (Ramp B) % EB I-66 Off-Ramp to SB Route 7 (Right-Turn Branch) % On-Ramp from SB Route 7 to EB I-66 (Ramp A) % Merge area of the ramps from EB I-66 and SB Route % EB I-66 Collector-Distributor Road Weaving Segment % Off-Ramp to West Falls Church Metro Station % Severely congested traffic Heavy congested traffic Moderate traffic Light traffic Table 6.3: Eastbound I-66 Ramps at Route 7 Traffic Operations 2025 Build AM Peak Hour 2025 Build AM Location Demand Throughput Speed Density Δ % (veh/hr) (veh/hr) (mph) (pc/ln/mi) EB I-66 Off-Ramp to Route 7 (Ramp B) % EB I-66 Off-Ramp to SB Route 7 (Right-Turn Branch) % Proposed connector ramp % On-Ramp from SB Route 7 to EB I-66 (Ramp A) % Merge area of the ramps from EB I-66 and SB Route % EB I-66 Collector-Distributor Road Weaving Segment % Off-Ramp to W. Falls Church Metro Station % Severely congested traffic Heavy congested traffic Moderate traffic Light traffic August 2017 Transform Interstate

58 Route 7 Connector Ramp: Modified Interchange Modification Report Figure 6.3 and Figure 6.4 show congestion maps for freeways and ramps in the study area during the AM peak hour for the 2025 No-Build and Build scenarios respectively. Figure 6.3: Freeway and Ramp Congestion Map 2025 No-Build AM Peak Hour Figure 6.4: Freeway and Ramp Congestion Map 2025 Build AM Peak Hour Transform Interstate 66 August

59 Route 7 Connector Ramp: Modified Interchange Modification Report From the tables and figures above, it can be concluded that for both the 2025 No-Build and Build scenarios, the eastbound I-66 ramp segments will operate with little or no congestion in the AM peak hour. Table 6.4 and Table 6.5 summarize the traffic operational conditions of the eastbound I-66 ramp segments near the Route 7 interchange during the PM peak hour for 2025 No-Build and Build scenarios respectively. Table 6.4: Eastbound I-66 Ramps at Route 7 Traffic Operations 2025 No-Build PM Peak Hour 2025 No-Build PM Location Demand Throughput Speed Density Δ % (veh/hr) (veh/hr) (mph) (pc/ln/mi) EB I-66 Off-Ramp to Route 7 (Ramp B) 1,135 1,094-4% EB I-66 Off-Ramp to SB Route 7 (Right-Turn Branch) % On-Ramp from SB Route 7 to EB I-66 (Ramp A) 1, % Merge area of the ramps from EB I-66 and SB Route 7 1, % EB I-66 Collector-Distributor Road Weaving Segment 1, % Off-Ramp to W. Falls Church Metro Station % Severely congested traffic Heavy congested traffic Moderate traffic Light traffic Table 6.5: Eastbound I-66 Ramps at Route 7 Traffic Operations 2025 Build PM Peak Hour 2025 Build PM Location Demand (veh/hr) Throughput (veh/hr) Δ % Speed (mph) Density (pc/ln/mi) EB I-66 Off-Ramp to Route 7 (Ramp B) % EB I-66 Off-Ramp to SB Route 7 (Right-Turn Branch) % Proposed connector ramp % On-Ramp from SB Route 7 to EB I-66 (Ramp A) 1, % Merge area of the ramps from EB I-66 and SB Route 7 1,321 1,132-14% EB I-66 Collector-Distributor Road Weaving Segment 1,421 1,197-16% Off-Ramp to W. Falls Church Metro Station % Severely congested traffic Heavy congested traffic Moderate traffic Light traffic August 2017 Transform Interstate

60 Route 7 Connector Ramp: Modified Interchange Modification Report Figure 6.5 and Figure 6.6 show congestion maps for freeways and ramps in the study area during the PM peak hour for the 2025 No-Build and Build scenarios respectively. Figure 6.5: Freeway and Ramp Congestion Map 2025 No-Build PM Peak Hour Figure 6.6: Freeway and Ramp Congestion Map 2025 Build PM Peak Hour Transform Interstate 66 August

61 Route 7 Connector Ramp: Modified Interchange Modification Report From the tables and figures above, in both the 2025 No-Build and Build scenarios, some of the eastbound I-66 ramp segments experience moderate congestion in the PM peak hour. The proposed connector ramp and its merge area with the southbound Route 7 on-ramp will operate at the similar levels of congestion as the No-Build scenario. It is noted that ramp densities in 2025 No-Build would be lower than those in existing. This is because that with the implementation of HOV 3+ restriction after 2020 ramp demand volumes in 2025 are expected to decrease as compared to the existing volumes. Eastbound Off-Ramp Queuing Conditions Table 6.6 summarizes the average and maximum queue lengths at the eastbound I-66 off-ramp approach to the intersection at Route 7 for the 2025 scenarios. Under the 2025 No-Build scenarios, the maximum queues would spill back to the freeway mainline during the PM peak hours. The proposed connector ramp in the Build scenarios would significantly reduce average and maximum queue lengths and eliminate the queue spilling back conditions. Table 6.6: Queue Lengths at the Eastbound I-66 Off-Ramp to Route No-Build vs. Build Scenarios 2025 AM Scenarios Ave. Queue (ft) Max. Queue (ft) No-Build Build No-Build PM Build * The shaded cell indicates the queue spills back to freeway mainline. Travel Time Table 6.7 shows the comparison of the travel times for vehicles destined to West Falls Church Metro station from eastbound I-66 between the No-Build and Build scenarios in the interim year Table 6.7: Average Travel Times to West Falls Church Metro 2025 No-Build vs. Build Scenarios From Merge point of northbound I-495 ramp with eastbound I-66 To West Falls Church Metro Garage entrance Peak Hour 2025 No-Build Travel Time (min) 2025 Build Travel Time (min) Difference (%) AM Peak % PM Peak % From the above table, the new connector ramp reduces the average travel time for vehicles by about 50 percent in both the 2025 AM and PM peak hours. The connector ramp allows vehicle to bypass the signalized intersections on Route 7 and Haycock Road and reach the Metro station in a direct path, thereby causing the reduction in travel time. Arterial Intersections Operations Table 6.8 and Table 6.9 summarize the arterial traffic operational results as measured by the average vehicle delays and level of congestion for all intersections within the study area during AM and PM peak hours for 2025 No-Build and Build scenarios. Detailed results on intersection operations such as movementlevel delays, throughputs, and queues are included in Appendix D. August 2017 Transform Interstate

62 Route 7 Connector Ramp: Modified Interchange Modification Report Table 6.8: Intersection Delay and Congestion Levels on Intersections 2025 AM Peak Hour Intersection 2025 No-Build AM Peak Hour 2025 Build AM Peak Hour Average Delay (sec/veh) Average Delay (sec/veh) Leesburg Pike(Route 7)/Pimmit Drive Leesburg Pike (Route 7)/Idylwood Road EB I-66 Off-Ramp/Leesburg Pike (Route 7) Leesburg Pike (Route 7)/Haycock Road/Shreve Road Haycock Rd/Falls Church Drive Haycock Rd/Park and Ride Road Falls Church Drive/Park and Ride Road Falls Church Drive/Metro Station Park and Ride Road/Metro Station Severely congested traffic Heavy congested traffic Moderate traffic Light traffic Table 6.9: Intersection Delay and Congestion Levels on Intersections 2025 PM Peak Hour Intersection 2025 No-Build PM Peak Hour 2025 Build PM Peak Hour Average Delay (sec/veh) Average Delay (sec/veh) Leesburg Pike(Route 7)/Pimmit Drive Leesburg Pike (Route 7)/Idylwood Road EB I-66 Off-Ramp/Leesburg Pike (Route 7) Leesburg Pike (Route 7)/Haycock Road/Shreve Road Haycock Rd/Falls Church Drive Haycock Rd/Park and Ride Road Falls Church Drive/Park and Ride Road Falls Church Drive/Metro Station Park and Ride Road/Metro Station Severely congested traffic Heavy congested traffic Moderate traffic Light traffic The arterial operational analysis results show that during both peak hours, the intersections operate at the same levels of congestion in both the Build and No-Build scenario. Specifically, though still under severe congestions, operational conditions at two key intersections will be improved in the Build scenarios during the PM peak hour. Compared to the 2025 No-Build scenario in the PM peak hour, the average delay at the intersection of eastbound I-66 off-ramp and Route 7 will reduce by 27 seconds per vehicle, and at the intersection of Route 7 and Haycock Road, will reduce by 58 seconds per vehicle in the Build scenario. This is primarily due to reduction in traffic volume at the southbound leftturn movement that is anticipated to be diverted to the new connector ramp Summary of 2025 Operations In the Build scenarios, traffic will be diverted from the southbound Route 7 left turn movement at the Haycock Road intersection to the proposed connector ramp. The eastbound I-66 ramp segments will Transform Interstate 66 August

63 Route 7 Connector Ramp: Modified Interchange Modification Report experience similar levels of congestion between the No-Build and Build scenario. The proposed connector ramp will operate at little or no congestion in the 2025 AM and PM peak hours. The new connector ramp reduces the travel time from eastbound I-66 to West Falls Church Metro station by about 50 percent in both the AM and PM peak hours. All the intersections on Route 7 and Haycock Road in the study area operate at the same levels of congestion during peak hours in both the No-Build and Build scenarios. The overall delays in the PM peak hour at Route 7 intersections of eastbound I-66 off-ramp and Haycock Road significantly reduce in the Build scenario due to traffic diverted to the new connector ramp DESIGN YEAR ANALYSIS Traffic Volumes Figure 6.7 and Figure 6.8 show the AM and PM peak-hour traffic demand volumes on freeway mainlines and local intersections within the study area for the 2040 No-Build and Build scenarios. The volumes for the intersections on Route 7 were adopted from the TaTTR. The volumes for the intersections on Haycock Road were estimated based on growth factors developed for the Route 7 and Haycock Road intersection and balanced with the rest of the network intersections. August 2017 Transform Interstate

64 Route 7 Connector Ramp: Modified Interchange Modification Report Figure 6.7: Design Year (2040) Peak-Hour Traffic Demand Volumes on Freeway and Ramp Transform Interstate 66 August

65 Route 7 Connector Ramp: Modified Interchange Modification Report Figure 6.8: Design Year (2040) Peak-Hour Traffic Demand at Intersections on Route 7 August 2017 Transform Interstate

66 Route 7 Connector Ramp: Modified Interchange Modification Report Table 6.10 shows the estimated volumes for the proposed connector ramp based on the methodology described in the Appendix C. As mentioned previously, the connector ramp will divert traffic that currently exits I-66 off-ramp to Route 7, merges with southbound Route 7 and turns left at the Route 7/Haycock Road intersection. Table 6.10: Estimated Traffic Volumes on the Proposed Connector Ramp Design Year 2040 Location AM Peak Hour Volumes PM Peak Hour Volumes 2040 No-Build 2040 Build 2040 No-Build 2040 Build Proposed Connector Ramp N/A 153 N/A 290 Eastbound left turn at the Route 7 and Haycock Road Intersection No-Build vs. Build Operations Freeway and Ramp Operations Table 6.11 and Table 6.12 summarize the traffic operational conditions of the eastbound I-66 ramp segments near the Route 7 interchange during the AM peak hour for 2040 No-Build and Build scenarios respectively. Table 6.11: Eastbound I-66 Ramps at Route 7 Traffic Operations 2040 No-Build AM Peak Hour 2040 No-Build AM Location Demand Throughput Speed Density Δ % (veh/hr) (veh/hr) (mph) (pc/ln/mi) EB I-66 Off-Ramp to Route 7 (Ramp B) % EB I-66 Off-Ramp to SB Route 7 (Right-Turn Branch) % On-Ramp from SB Route 7 to EB I-66 (Ramp A) % Merge area of the ramps from EB I-66 and SB Route % EB I-66 Collector-Distributor Road Weaving Segment % Off-Ramp to W. Falls Church Metro Station % Severely congested traffic Heavy congested traffic Moderate traffic Light traffic Table 6.12: Eastbound I-66 Ramps at Route 7 Traffic Operations 2040 Build AM Peak Hour Location Demand (veh/hr) Throughput (veh/hr) 2040 Build AM Δ % Speed (mph) Density (pc/ln/mi) EB I-66 Off-Ramp to Route 7 (Ramp B) % EB I-66 Off-Ramp to SB Route 7 (Right-Turn Branch) % Proposed connector ramp % On-Ramp from SB Route 7 to EB I-66 (Ramp A) % Merge area of the ramps from EB I-66 and SB Route % EB I-66 Collector-Distributor Road Weaving Segment % Off-Ramp to W. Falls Church Metro % Severely congested traffic Heavy congested traffic Moderate traffic Light traffic Transform Interstate 66 August

67 Route 7 Connector Ramp: Modified Interchange Modification Report Figure 6.9 and Figure 6.10 show congestion maps for freeways and ramps in the study area during the AM peak hour for the 2040 No-Build and Build scenarios respectively. Figure 6.9: Freeway and Ramp Congestion Map 2040 No-Build AM Peak Hour Figure 6.10: Freeway and Ramp Congestion Map 2040 Build AM Peak Hour August 2017 Transform Interstate

68 Route 7 Connector Ramp: Modified Interchange Modification Report From the tables and figures above, it can be concluded that for both the 2040 No-Build and Build scenarios, the eastbound I-66 ramp segments will operate with little or no congestion in the AM peak hour. Table 6.13 and Table 6.14 summarize the traffic operational conditions of the eastbound I-66 ramp segments near Route 7 interchange during the PM peak hour for 2040 No-Build and Build scenarios respectively. Table 6.13: Eastbound I-66 Ramps at Route 7 Traffic Operations 2040 No-Build PM Peak Hour 2040 No-Build PM Location Demand Throughput Speed Density Δ % (veh/hr) (veh/hr) (mph) (pc/ln/mi) EB I-66 Off-Ramp to Route 7 (Ramp B) % EB I-66 Off-Ramp to SB Route 7 (Right-Turn Branch) % On-Ramp from SB Route 7 to EB I-66 (Ramp A) % Merge area of the ramps from EB I-66 and SB Route % EB I-66 Collector-Distributor Road Weaving Segment % Off-Ramp to W. Falls Church Metro % Severely congested traffic Heavy congested traffic Moderate traffic Light traffic Table 6.14: Eastbound I-66 Ramps at Route 7 Traffic Operations 2040 Build PM Peak Hour 2040 Build PM Location Demand (veh/hr) Throughput (veh/hr) Δ % Speed (mph) Density (pc/ln/mi) EB I-66 Off-Ramp to Route 7 (Ramp B) % EB I-66 Off-Ramp to SB Route 7 (Right-Turn Branch) % Proposed connector ramp % On-Ramp from SB Route 7 to EB I-66 (Ramp A) % Merge area of the ramps from EB I-66 and SB Route 7 1, % EB I-66 Collector-Distributor Road Weaving Segment 1,230 1,049-15% EB I-66 Off-Ramp to Route % Severely congested traffic Heavy congested traffic Moderate traffic Light traffic Transform Interstate 66 August

69 Route 7 Connector Ramp: Modified Interchange Modification Report Figure 6.11 and Figure 6.12 show congestion maps for freeways and ramps in the study area during the PM peak hour for the 2040 No-Build and Build scenarios respectively. Figure 6.11: Freeway and Ramp Congestion Map 2040 No-Build PM Peak Hour Figure 6.12: Freeway and Ramp Congestion Map 2040 Build PM Peak Hour August 2017 Transform Interstate

70 Route 7 Connector Ramp: Modified Interchange Modification Report From the tables and figures above, in both the 2040 No-Build and Build scenarios, some of the eastbound I-66 ramp segments experience moderate congestion in the PM peak hour. The proposed connector ramp and its merge area with the southbound Route 7 on-ramp will operate at the similar levels of congestion as the No-Build scenario. Eastbound Off-Ramp Queuing Conditions Table 6.15 summarizes the average and maximum queue lengths at the eastbound I-66 off-ramp approach to the intersection at Route 7 for the 2040 scenarios. Similar to the 2025 scenarios, the proposed connector ramp in Build scenarios would significantly reduce average and maximum queue lengths, and there would be no queue spilling back conditions under 2040 Build scenarios. Table 6.15: Queue Lengths at the Eastbound I-66 Off-Ramp to Route No-Build vs. Build Scenarios 2040 AM 2040 PM Scenarios Ave. Queue (ft) Max. Queue (ft) No-Build Build No-Build Build Travel Time Table 6.16 shows the comparison of the travel times for vehicles destined to West Falls Church Metro station from eastbound I-66 between the No-Build and Build scenarios in the design year Table 6.16: Average Travel Times to West Falls Church Metro 2040 No-Build vs. Build Scenarios From Merge point of northbound I-495 ramp with eastbound I-66 To West Falls Church Metro Garage entrance Peak Hour 2040 No-Build Travel Time (min) 2040 Build Travel Time (min) Difference (%) AM Peak % PM Peak % From the above table, the new connector ramp reduces the average travel time for vehicles by about 47 percent in 2040 AM peak hour and 46 percent in 2040 PM peak hour. Arterial Intersections Operations Table 6.17 and Table 6.18 summarize the arterial traffic operational results as measured by the average vehicle delays and level of congestion for all intersections within the study area during AM and PM peak hours for 2040 No-Build and Build scenarios. Detailed results on intersection operations such as movementlevel delays, throughputs, and queues are included in the Appendix D. Transform Interstate 66 August

71 Route 7 Connector Ramp: Modified Interchange Modification Report Table 6.17: Intersection Delay and Congestion Levels during 2040 No-Build and Build AM Peak Hour Intersection 2040 No-Build AM Peak Hour 2040 Build AM Peak Hour Average Delay (sec/veh) Average Delay (sec/veh) Leesburg Pike(Route 7)/Pimmit Drive Leesburg Pike (Route 7)/Idylwood Road EB I-66 Off-Ramp/Leesburg Pike (Route 7) Leesburg Pike (Route 7)/Haycock Road/Shreve Road Haycock Rd/Falls Church Drive Haycock Rd/Park and Ride Road Falls Church Drive/Park and Ride Road Falls Church Drive/Metro Station Park and Ride Road/Metro Station Severely congested traffic Heavy congested traffic Moderate traffic Light traffic Table 6.18: Intersection Delay and Congestion Levels during 2040 No-Build and Build PM Peak Hour Intersection 2040 No-Build PM Peak Hour Average Delay (sec/veh) 2040 Build PM Peak Hour Average Delay (sec/veh) Leesburg Pike(Route 7)/Pimmit Drive Leesburg Pike (Route 7)/Idylwood Road EB I-66 Off-Ramp/Leesburg Pike (Route 7) Leesburg Pike (Route 7)/Haycock Road/Shreve Road Haycock Rd/Falls Church Drive Haycock Rd/Park and Ride Road Falls Church Drive/Park and Ride Road* Falls Church Drive/Metro Station Park and Ride Road/Metro Station * This intersection is still under an all-way stop control in the 2040 No-Build conditions, but will be signalized in 2040 Build conditions. Severely congested traffic Heavy congested traffic Moderate traffic Light traffic From the above tables, during both peak hours, the intersections operate at similar levels of congestion in both the Build and No-Build scenario. During the PM peak hour in 2040, all Route 7 intersections will still operate at severely congested conditions in Build scenarios, same as in the No-Build. Traffic demands on Route 7 in 2040 PM peak hour are so high that the diverted traffic by the proposed connector ramp is not significant as compared to the overall Route 7 traffic demand. Therefore, the diversion would only benefit operations on the southbound approach at Route 7/ Haycock Road intersection, but not significantly improve the overall intersection performance and other adjacent intersections. It should be noted that the intersection of Falls Church Drive and Park and Ride Road is currently operating with an all-way stop control. In the 2040 No-Build scenarios, this intersection will still operate at light traffic conditions with the same type of traffic control. However, with the proposed connector ramp, an August 2017 Transform Interstate

72 Route 7 Connector Ramp: Modified Interchange Modification Report additional 300 vehicles will be diverted to this intersection during the PM peak hour in the 2040 Build scenario. The PM peak hour volume at the single-lane southbound approach of this intersection will increase from 286 vehicles in the 2040 No-Build scenario to 579 vehicles in the 2040 build scenario. With these volume, the intersection will be severely congested with excessive southbound queues if still under all-way stop control. With a signal control, the congestion at this intersection is reduced significantly. Therefore, it is recommended that VDOT should monitor the traffic conditions at this intersection after 2025 and signalize it when the operational conditions deteriorate and the signal warrants are met. At the intersection of Route 7 and Haycock Road, the average delay during the AM peak hour will reduce by 24 seconds in the 2040 Build scenario as compared to 2040 No-Build. The congestion level will be improved from severe congestion to heavy congestion. During the PM peak hour, the average delay will be slightly reduced by 8 seconds Summary of 2040 Operations The 2040 evaluations are consistent with the results from 2025 evaluations. In the Build scenarios, traffic will be diverted from the southbound Route 7 left turn movement at the Haycock Road intersection to the proposed connector ramp. The eastbound I-66 ramp segments will experience similar levels of congestion between the No-Build and Build scenario. The proposed connector ramp will operate at little or no congestion in the 2040 AM and PM peak hours. The new connector ramp reduces the travel time from eastbound I-66 to West Falls Church Metro station by about minutes (46 47 percent) in both the AM and PM peak hours. All the intersections on Route 7 and Haycock Road in the study area operate at similar congestions levels in both the No-Build and Build scenarios. The overall intersection delay at Route 7 and Haycock Road reduces in the Build scenario due to traffic diverted to the new connector ramp. Transform Interstate 66 August

73 P for 7. SAFETY AND CRASH ANALYSIS This chapter presents the safety analysis that was conducted for this study based on reported crash data available from the last five years ( ) in the VDOT database for the study area, including I-66 eastbound mainline, Route 7 (Leesburg Pike) interchange and ramps, and the Route 7 and Haycock Road intersection. The analysis was performed in accordance with the methods identified in FHWA s Interstate System Access Informational Guide. 7.1 DATA COLLECTION AND ANALYSIS METHODOLOGY Five-year crash data for the I-66/Route 7 interchange modification study area was obtained from the VDOT 1 tableau webpagep0f the most recent five-year period available ( ). The crash data covers the study area and includes the I-66 eastbound mainline between the diverge segment of the I-66 eastbound off-ramp and the merge segment of the Route 7 on-ramp, ramps within the I-66/Route 7 interchange, Route 7 between Pimmit Drive intersection and Haycock Road intersection, as well as Haycock Road between Route 7 and Park-and-Ride intersection. The red shaded areas in Figure 7.1 illustrate the overall areas for which crash data was collected for the analysis. Furthermore, the areas marked in green, sections of the eastbound I-66 off-ramp and on-ramp to/from Route 7 and the Route 7 and Haycock Road intersection, represent the safety focus areas with highest likelihood of being influenced by the diverted traffic of the new connector ramp. Figure 7.1: Historical Crash Data Collection Area 1 Transform Interstate 66 August

74 Route 7 Connector Ramp: Modified Interchange Modification Report 16TUsing this data, crash analysis has been performed for existing conditions including the I-66 interstate mainline, ramps, and intersections on Route 7 within the study area, similar to the area as documented for traffic data collection. A combination of qualitative and quantitative analyses has been used to evaluate safety in the study area. Qualitative analyses, including documenting existing crash frequencies, severity, and predominant crash types on the I-66 mainline exit segment and the selected ramps with volumes/ geometry changes, has been summarized. Where possible, the safety issues and contributing factors to crashes have been identified for the existing condition. Crash data has been summarized by location, type, and severity to identify existing crash patterns and safety concerns in the study area. 16TQuantitative analyses, using AASHTO Highway Safety Manual (HSM) methodologies within the Enhanced Interchange Safety Analysis Tool (ISATe), has also been used to evaluate an estimated predicted safety performance (crash frequency) comparison between the No-Build and Build conditions for the interim year 2025 and design year The predictive crash methods detailed in the HSM were used to provide input into the roadway design process to evaluate safety for the various design options, including any recommended strategies to improve the safety performance of the proposed Build condition. 7.2 HISTORICAL CRASH ANALYSIS FOR EXISTING CONDITION Study Area Crash Frequency and Trend Summary Table 7.1 below provides the summary of the total crashes reported in the five-year period within the study area. The total crashes at Route 7 are much higher than the other three subareas and consist of over 50 percent of the total crashes within the study area. Injury crashes are half of the total crashes on Route 7, whereas property-damage-only (PDO) crashes are 60 to 70 percent of the total crash at I-66 mainline, I- 66/Route 7 interchange, and Haycock Road. Fatal crashes are not a significant factor in this study area. Table 7.1: Crash Summary by Roadway Segment and Severity within the General Study Area Location Fatality Injury PDO Total Crashes Eastbound I-66 Mainline Ramps Route Haycock Road Figure 7.2 below shows the summary of the total crashes by crash type at the four subarea locations. It indicates that the most frequent crash types are rear-end crash and angle crash, especially on freeway and local streets. Eastbound I-66 mainline rear-end crashes are 70 percent of the crashes within the mainline component of the study area. For Route 7, rear-end crash and angle are the most predominant crash types with about 56 percent and 32 percent of the total Route 7 crashes, respectively. August 2017 Transform Interstate

75 Route 7 Connector Ramp: Modified Interchange Modification Report Number of Crashes I-66 EB Mainline Ramps Route 7 Haycock Rd Rear End Deer Ped Other Angle Head On Sideswipe - Same Direction Fixed Object in Road Non-Collision Fixed Object - Off Road Figure 7.2: Total Crash Summary by Collision Type Safety Focus Area Crash Frequency and Trend Summary Figure 7.3 illustrates the areas where the greatest potential impact to crashes would be expected to occur as a result of the proposed project. This includes the two eastbound ramps and the Route 7 and Haycock Road intersection. This safety focus area serves as the area within which the quantitative analysis and/or HSM evaluation has been performed to evaluate the safety impact of the proposed project. Table 7.2 summarizes the past five-year crash summary by severity within this focus area subdivided by location. Transform Interstate 66 August

76 Route 7 Connector Ramp: Modified Interchange Modification Report Figure 7.3: Study Area of HSM Safety Analysis Table 7.2: Total Crash Summary by Severity by Safety Focus Area Location Fatality Injury PDO Total Crashes Route 7 and Haycock Road Intersection Southbound Route 7 On-Ramp to Eastbound I-66 (Ramp A) Eastbound I-66 Off-Ramp to Southbound Route 7 (Ramp B) The historical crash summary indicates the Route 7 and Haycock Road intersection currently experiences over 12 crashes every year, and injury crashes consisting of more than half of the total. There were few ramp-related crashes on the two ramps: southbound Route 7 to eastbound I-66 (Ramp A) and eastbound I- 66 to southbound Route 7 (Ramp B). The southbound Route 7 to eastbound I-66 ramp had seven crashes in total over the past five years compared to only one crash on the eastbound I-66 to southbound Route 7 ramp, which is expected since the ramp of southbound Route 7 to eastbound I-66 is a half-mile longer than the other ramp, and there are two more ramp merging/ diverging points and one more weave section along the ramp. Figure 7.4 shows detailed crash severity summary at the Route 7 and Haycock Road intersection over the past five years. Over 83 percent of total crashes at this intersection resulted in property damage only (PDO) or no-visual injury. No fatality occurred in the past five years. August 2017 Transform Interstate

77 Route 7 Connector Ramp: Modified Interchange Modification Report Number of Crashes A.Ambulatory Injury B.Visible Injury C.Non-Visible Injury PDO.Property Damage Only Route 7/Haycock Road Intersection Figure 7.4: Route 7 and Haycock Road Intersection Crash Summary by Severity Figure 7.5 shows the numbers of crash by collision type at this intersection. Angle crash was the highest type of intersection crashes, with more than 30 percent happening at this intersection because of turning conflicts; while the second highest crash type was rear-end. These two predominate crash types show high traffic volumes and vehicle density at this intersection, as well as a significant amount of left-turn movement Number of Crashes Rear End Ped Angle Sideswipe - Same Direction Route 7/Haycock Road Intersection 5 2 Fixed Object - Off Road Figure 7.5: Route 7 and Haycock Road Intersection Crash Summary by Collision Type Transform Interstate 66 August

78 Route 7 Connector Ramp: Modified Interchange Modification Report Figure 7.6 and Figure 7.7 summarize detailed crash severity and collision type on the eastbound I-66 offramp to southbound Route 7 and the southbound Route 7 on-ramp to eastbound I Number of Crashes EB I-66/SR 7 Ramp Intersection EB I-66 to SB Route 7 Ramps B.Visible Injury C.Non-Visible Injury PDO.Property Damage Only Figure 7.6: Crash Summary of Focus Ramp Areas by Severity Number of Crashes EB I-66/SR 7 Ramp Intersection EB I-66 to SB Route 7 Ramps Rear End Deer Angle Fixed Object - Off Road Figure 7.7: Crash Summary of Focus Ramp Areas by Collision Type August 2017 Transform Interstate

79 Route 7 Connector Ramp: Modified Interchange Modification Report There were eight crashes on these two ramps over the past five years. Rear-end and fixed object were the two key types of ramp-related crashes over five years, and the two rear-ends occurred at the downstream of the off-ramp to West Falls Church Metro station. 7.3 EXPECTED SAFETY IMPACT OF BUILD OPTION ON THE SAFETY FOCUS AREA Evaluation Based on Historical Crash Data In the Build scenario, the proposed connector ramp between eastbound I-66 to southbound Route 7 ramp and southbound Route 7 to eastbound I-66 ramp is anticipated to divert traffic from local arterial routes to the connector ramp to access the West Falls Church Metro station. It was estimated that approximately 2,100 vehicles per day by 2025 interim year and 2040 design year shifts from local routes to the connector ramp. The reduced volume at the Route 7 and Haycock Road intersection would relieve the congestion at this intersection, reduce vehicle delay time at the signal, improve the traffic operations, as well as reduce potential crashes caused by those vehicles on southbound Route 7 trying to turn left to Haycock Road. The Build scenario would also benefit the segment of Route 7 corridor from I-66 interchange to Haycock Road intersection, as well as Haycock Road from Route 7 to Park-and-Ride because of the reduced crashes. On the other hand, the added ramp connector would increase the conflict points on the ramps, one diverging point and one merging point, which would increase the potential for rear-end and sideswipe crashes. The added traffic would also increase the density at the weave segment of northbound Route 7 on-ramp and southbound Route 7 off-ramp to West Falls Church Metro station. While the alternative widens the ramp of eastbound I-66 to southbound Route 7 from one lane to two lanes at the beginning of the ramp exit to allow vehicles to choose the left-side lane to the new connector, increasing the number of lanes would require narrowed ramp shoulder widths and lane widths which might also increase crash potential as compared to the No-Build scenario Evaluation Based on HSM analysis Quantitative analysis using the ISATe HSM analysis tool was developed to evaluate the freeway exit and ramps including eastbound I-66 off-ramp to southbound Route 7, southbound Route 7 on-ramp to eastbound I-66, and eastbound I-66 off-ramp to West Falls Church Metro station for the No-Build conditions with/without existing crash input and the Build conditions. For arterials, a modified/limited application of HSM analysis was used to evaluate the expected benefit of diverting vehicles from the arterials to the ramps. The HSM prediction methods were used to evaluate the existing and proposed conditions within the focus study area. Freeways and Ramps To evaluate the true impact of the proposed connector requires an understanding of how the existing condition is performing relative to other similar sites. This will identify if there is an existing safety need and potential for improvement, if the site is performing as expected, or if the site is performing better than expected. Therefore, the first step was to evaluate how the existing condition was performing compared to peer sites. This involved estimating the predicted crash frequency for similar sites and comparing that estimate to a calculated value incorporating historical crash data, referred to as the expected crash frequency for the site. A comparison of the two illustrates how the subject site is performing as compared to peer sites with similar characteristics. The comparison value is referred to as the Potential for Safety Improvement (PSI) of the study/project area. Where the difference is positive, there is considered to be a potential for improvement as this reflects that the site is experiencing more crashes on average than would be predicted at other peer sites. Similarly, a negative value for the PSI indicates that the study site is experiencing fewer Transform Interstate 66 August

80 Route 7 Connector Ramp: Modified Interchange Modification Report crashes on average than other peer sites. AASHTO Highway Safety Manual 2014 Supplement provides more information on the HSM Predictive Methods. Table 7.3 summarizes the predicated and expected crash frequency for the existing conditions. Crash frequencies are reported in KABCO severity classification. Table 7.3: Total Crash Frequencies for Existing Condition and Potential for Safety Improvement (PSI) Alternative Crashes by Facility Component Total K A B C PDO Freeway segments Predicted Existing Ramp segments (2016) Total crashes/year Expected Existing (2016) Potential for Safety Improvement (PSI) (2016) Freeway segments Ramp segments Total crashes/year Freeway segments Ramp segments Total crashes/year As seen from the results, the freeway segments within the study area have potential for safety improvement, while the existing ramps already had a lower crash frequencies than the predicted results. For the proposed conditions, only predicted crash frequencies can be calculated for similar sites for the No- Build and Build scenarios, because crash data would not be available for the proposed condition. Therefore a predicted-to-predicted comparison of the crash frequency between the No-Build and Build conditions can be performed to assess the difference in predicted crash frequency, quantifying the relative difference in predicted safety performance of the Build as compared to the No-Build conditions. Table 7.4 and Table 7.5 show the estimated crash frequency calculated results by interim year 2025 and design year 2040 respectively for the No-Build and Build conditions. The last three rows of each table show the predicted crash difference between the No-Build and Build conditions for the two future years. Table 7.4: Crash Frequencies Summary for No-Build and Build Conditions in 2025 Alternative Crashes by Facility Component Total K A B C PDO Freeway segments Predicted No-Build Ramp segments (2025) Total crashes/year Predicted Build (2025) Difference in Crashes (2025) Freeway segments Ramp segments Total crashes/ year Freeway segments Ramp segments Total crashes/year August 2017 Transform Interstate

81 Route 7 Connector Ramp: Modified Interchange Modification Report Table 7.5: Crash Frequencies Summary for No-Build and Build Conditions in 2040 Alternative Crashes by Facility Component Total K A B C PDO Freeway segments Predicted No-Build Ramp segments (2040) Total crashes/year Predicted Build (2040) Difference in Crashes (2040) Freeway segments Ramp segments Total crashes/ year Freeway segments Ramp segments Total crashes/year Compared to the predicted No-Build conditions, freeway segments under the Build conditions have almost the same performance for both 2025 and 2040 years. This is reflective of the relatively minor difference between No-Build conditions and the Build design such as minor shoulder width, speed change, lane distance changes, etc. However, ramp segments have a slight increase in crashes per year as expected because of the additional ramp link, higher traffic density on the combined ramp, two additional merging/ diverging points, in addition to minor lane/shoulder widths change. The predicted increase in annual crash frequency per year in the 2040 Build condition is approximately 9 percent as compared to the No-Build conditions within the focus study area. However, these amounts are equivalent to less than one predicted crash per year. A detailed breakdown of the predicted increase in annual crash frequency on each of the ramps is shown in Table 7.6 and Table 7.7 for interim year 2025 and design year 2040, respectively. The increase in annual crash potential on each individual ramp are marginal. Another key observation is that the higher severity fatal and incapacitating injury crashes (K and A) are predicted not to change with the primary differences being in the lower severity and property-damage-only crashes. Table 7.6: Crash Frequencies Summary by Ramp for No-Build and Build Conditions in 2025 Alternative Crashes by Facility Component Total K A B C PDO Predicted Southbound Route 7 on-ramp to eastbound I No-Build Eastbound I-66 off-ramp to southbound Route (2025) Off-ramp to West Falls Church Metro station Predicted Build (2025) Difference in Crashes (2025) Southbound Route 7 on-ramp to eastbound I Eastbound I-66 off-ramp to southbound Route Off-ramp to West Falls Church Metro station Southbound Route 7 on-ramp to eastbound I Eastbound I-66 off-ramp to southbound Route Off-ramp to West Falls Church Metro station Transform Interstate 66 August

82 Route 7 Connector Ramp: Modified Interchange Modification Report Table 7.7: Crash Frequencies Summary by Ramp for No-Build and Build Conditions in 2040 Alternative Crashes by Facility Component Total K A B C PDO Predicted Southbound Route 7 on-ramp to eastbound I No-Build Eastbound I-66 off-ramp to southbound Route (2025) Off-ramp to West Falls Church Metro station Predicted Build (2025) Difference in Crashes (2025) Southbound Route 7 on-ramp to eastbound I Eastbound I-66 off-ramp to southbound Route Off-ramp to West Falls Church Metro station Southbound Route 7 on-ramp to eastbound I Eastbound I-66 off-ramp to southbound Route Off-ramp to West Falls Church Metro station Arterial Intersection While the HSM models sufficiently fit the existing and the proposed Build conditions of the freeway/interchange components of the study area to provide quantitative analysis, it was determined that complete HSM analysis of the arterials would not provide the same level of accuracy as the freeway at the cost of a much higher level of effort. Specifically, the HSM models were not an ideal fit for the arterial system and would likely under-predict crash frequency for the surface streets within the study area limiting the benefit of a full quantitative analysis of the arterials. While HSM models consider driveways, turn lanes, and other components of the arterial system, there are an excess of access management and other issues along Route 7 such as multiple high-volume driveways, concrete and grass median areas, and midblock crosswalk that complicate the arterial analysis. These coupled with the lack of AADT volume data for both the primary roads and major driveways would result in analysis of a lower confidence level than for the freeway/ramps components of the study area at a much higher level of effort. Therefore, for the arterials, the HSM methods were applied generally for the primary arterial intersection, Route 7 and Haycock Road intersection, to estimate the anticipated benefit as a result of diverting traffic from the arterial to the ramp connector, and a more detailed analysis of the arterial was not performed. While the arterials were not evaluated using the same methods of quantitative analysis, HSM methods were still used to approximate the benefit to the Route 7 and Haycock Road intersection to provide for perspective as to the potential for improvement at key locations on the arterials. This intersection would be expected to receive the most measurable benefit as a result of the reduction of volume through the intersection. The estimated intersection related crash frequency was calculated using the major and minor AADTs as the 2 independent variables according to the basic equation below (presented in HSM chapter 12P1F P). Where, N = Predicted intersection related crash frequency, NN = ee [aa+bb IIII AAAAAAAA mmmmmmmmmm +cc IIII(AAAAAAAA mmmmmm )] AADTRmajR = Average daily traffic volume (vehicles/day) for major road (both directions of travel combined), AADTRminR =Average daily traffic volume (vehicles/day) for minor road (both directions of travel combined), 2 Equation on p.12-29, and Equation on p.12-31, Highway Safety Manuel, 1 st Edition, AASHTO August 2017 Transform Interstate

83 Route 7 Connector Ramp: Modified Interchange Modification Report a, b, c = Regression coefficients, can be obtained from HSM Tables and Table 7.8 summarizes the input values at the Route 7 and Haycock Road intersection for 2040 No-Build and Build conditions and the calculated multiple and single vehicle crash frequency for AADT volumes were estimated by applying K factors to the forecasted peak-hour volumes developed for the project for use in the traffic analysis (see Figure 6.6 for complete volume data). Note that the estimated crash frequency is provided to approximate the benefit of a similar facility by reducing traffic volumes as a result of redirecting traffic along the ramp connector. It is based on AADT alone with no consideration for other intersection design variables (in that intersection has not been adjusted from HSM base condition to site condition), however those variables are assumed to remain consistent between No-Build and Build conditions and therefore would have little bearing on the results of this analysis. Table 7.8: AADT and Estimated Crash Frequencies at Route 7 and Haycock Road Intersection for 2040 No-Build and Build Conditions No-Build Build AADT and Estimated Crash Minor Road Major Road Minor Road Major Road Frequencies Haycock Shreve SB NB Haycock Shreve SB NB Road Road Route 7 Route 7 Road Road Route 7 Route 7 Peak-Hour Volume K factor* AADT Estimated Link AADT Yearly Crash Frequency** *K factor was obtained from the VDOT, Daily Traffic Volume Estimates, and jurisdiction report (29), Fairfax County. **Estimated Crash Frequency for a similar facility based only on AADT with no other adjustments. As shown in Table 7.8, the estimated number of predicted crashes per year were 30.9 and 29.7 for the No- Build and Build conditions, respectively, approximately 4.0 percent in crash reduction for the Build condition as compared to the No-Build. 7.4 SUMMARY AND CONCLUSION The five-year crash data identifies the Route 7 corridor and the intersection of Route 7 and Haycock Road as a high-frequency crash area. The predominant crash types at these locations were rear-end and angle collision. A possible contributing factor for these types of crashes is severe congestion and a large amount of traffic choosing the intersection to go to West Falls Church Metro station. A calculation of the predicted impact of the freeway and ramps indicates minimal impact on the freeway and an expected 9 percent higher frequency for the ramps. However, based on the review of existing crash data, there were very few crashes on the ramps, and the expected crash frequency was lower than the predicted result for the existing conditions indicating the ramp is currently performing better than other peer sites. As noted previously, it is expected that the impact on the ramps should be largely offset by the congestion relief on local streets. While detailed quantitative analyses were not performed, a reduction in traffic volumes would have a benefit of at least 5 percent reduction in crashes at the Route 7 and Haycock Road intersection alone, illustrating the anticipated benefit to the arterial roadway system. The evaluation of the local system was limited to one intersection only, therefore the anticipated benefit would likely be greater if considering the entire section of roadway along the current travel path of the diverted vehicles. The proposed connector ramp will divert traffic from going through southbound segment of Route 7 between the off-ramp and Transform Interstate 66 August

84 Route 7 Connector Ramp: Modified Interchange Modification Report Haycock Road. This will reduce the number of vehicles weaving across two lanes to make difficult left turns at already-congested Route 7/Haycock Road intersection, hence would reduce the crash potentials on this segment. In conclusion, the Preferred Alternative in the Build condition is predicted to have minimal negative safety impacts within the study area, and adverse impacts would be expected to be minor within the interchange based on the existing condition and the quantitative analysis. While it cannot be specifically quantified, based on the comparisons of the crash data and predicted crash frequency between the Build and No-Build conditions, the reduction in crashes as a result of diverting traffic from the heavily congested and complex arterial system is anticipated to exceed the slight increase in predicted crashes as a result of the addition of the ramp connector. August 2017 Transform Interstate

85 Transform 66 Inside the Beltway Route 7 Connector Ramp Project Modified Interchange Modification Report AUGUST 2017 State Project Number: A-493,P101, C501, B686; UPC: Federal Project Number: NHPP-066-1(356) Fairfax County, Virginia

86 Transform 66 Inside the Beltway Route 7 Connector Ramp Project Modified Interchange Modification Report Appendix A Justification of Need Technical Memorandum

87 TRANSFORM I-66 INSIDE THE BELTWAY EASTBOUND I-66 EXIT 66 OFF-RAMP AT ROUTE 7 CONNECTOR RAMP TO ACCESS WEST FALLS CHURCH METRO AND NORTHERN VIRGINIA CENTER JUSTIFICATION OF NEED January 30, 2017 The West Falls Church Metro station (herein referenced as Metro station ), located adjacently southeast to the interchange of I-66 and Route 7 currently does not have direct access from I-66 eastbound. Instead, vehicles must exit I-66, turn right to head south on Route 7 toward Falls Church, turn left at the signalized intersection at Haycock Road 1500 feet downstream, and then turn left onto Falls Church Drive, as shown in Figure 1 below. The vehicle path, as shown in blue below, is approximately one mile in length from the I-66 exit to the Metro station garage entrance and kiss-and-ride area. Vehicles destined for the Northern Virginia Center University of Virginia/Virginia Tech campus must also travel on this route. However, vehicles coming from either direction of Route 7 may use the on-ramps to eastbound I-66 in order to directly access the Metro station, surrounding parking / kiss-and-ride facilities, and campus. Figure 1: Aerial Map of Eastbound I-66 Exit 66 to Route 7 and West Falls Church Metro

88 JUSTIFICATION OF NEED Eastbound I-66 Exit 66 Off-Ramp at Route 7 Connector Ramp to Access West Falls Church Metro VDOT has identified operational and safety issues associated with the current configuration and vehicle route described above. Heavy traffic volumes and corresponding congestion along eastbound Route 7 result in queuing that spills back from the intersection of Haycock Road to the interchange with I-66 during AM and PM peak periods. As a result, vehicles exiting from I-66 and attempting to turn left on Haycock Road have difficulty maneuvering into the left turn (by crossing two adjacent lanes of through traffic) prior to reaching the intersection. The intersection currently performs at LOS E in the AM peak hour and LOS F in the PM peak hour, based on 2016 turning movement counts. Detailed intersection Measures of Effectiveness are shown in Tables 1 and 2 below for the morning and evening peaks, respectively. As seen in the results, the south-eastbound left turn movement (SB in the tables) from Route 7 to Haycock Road has some of the worst delays and queues of any movement in the intersection. The south-eastbound through movement also reflects similar problematic delays and queuing. While the volume turning left from Route 7 to Haycock Road is not entirely comprised of traffic destined for the Metro Station or the Northern Virginia Center campus, that route path does contribute a significant portion of the overall traffic attempting to turn left, which has notable impacts on the intersection approach and the overall performance of the intersection. Even though this movement is served by two left turn bays, the capacity cannot accommodate the demand, and the queuing from the through movement blocks traffic originating from eastbound I-66 from even gaining access to the dual left turn bays. Based on analysis performed as part of the I-66 EB Widening Environmental Assessment and supporting Traffic and Transportation Technical Report, this condition will worsen in future years (2040 Design Year) due to increasing demands at the intersection of Route 7 and Haycock Road. Transform I-66 Inside the Beltway January 30, 2017 Page 2 of 7

89 JUSTIFICATION OF NEED Eastbound I-66 Exit 66 Off-Ramp at Route 7 Connector Ramp to Access West Falls Church Metro 2016 Existing AM Measures of Effectiveness Intersection Movement Demand (veh/hr) Thruput (veh/hr) Δ % Movement Delay (sec/veh) Movement LOS Approach Delay (sec/veh) Approach LOS Intersection Delay (sec/veh) Intersection LOS Storage (ft) Avg. Queue (ft) Max. Queue (ft) EBT % 86.0 F EBR % 92.0 F 87.0 F EBL % 88.0 F SBT % 49.9 D SBR % 21.2 C 66.5 E Leesburg Pike (NB/SB) Haycock Road (WB) Shreve Road (EB) SBL % F E WBT % 70.7 E WBR % 77.6 E 71.7 E WBL % 63.2 E NBT % 40.6 D NBR % 42.3 D 44.1 D NBL % F Transform I-66 Inside the Beltway January 30, 2017 Page 3 of 7

90 JUSTIFICATION OF NEED Eastbound I-66 Exit 66 Off-Ramp at Route 7 Connector Ramp to Access West Falls Church Metro 2016 Existing PM Measures of Effectiveness Intersection Movement Demand (veh/hr) Thruput (veh/hr) Δ % Movement Delay (sec/veh) Movement LOS App Delay (sec/veh) Approach LOS Intersection Delay (sec/veh) Intersection LOS Storage (ft) Avg. Queue (ft) Max. Queue (ft) EBT % 69.9 E EBR % 73.5 E 86.2 F EBL % F SBT % F Leesburg Pike (NB/SB) Haycock Road (WB) SBR % F F SBL % F F Shreve Road (EB) WBT % F WBR % F F WBL % F NBT % F NBR % F F NBL % F Transform I-66 Inside the Beltway January 30, 2017 Page 4 of 7

91 JUSTIFICATION OF NEED Eastbound I-66 Exit 66 Off-Ramp at Route 7 Connector Ramp to Access West Falls Church Metro Field observations and citizen feedback provided in recent public meetings demonstrate that some vehicles are unable to effectively execute the lanes changes from the right side of Route 7 to the left side due to the low availability of gaps in traffic, which can often be stopped and bumper-to-bumper. Consequently, some vehicles either turn into the McDonald s parking lot in the southwest quadrant of the intersection and circle around, or continue to Birch Street, turn left, and cut through the Giant/Falls Plaza Shopping Center parking lot to get back to Haycock Road. VDOT Traffic Engineering has been studying the issue over the past year and assessing options to address the operational problems and corresponding safety concerns. The issue of direct connectivity also impacts buses that would travel along the same route, which impacts schedule reliability and may reduce the viability of taking transit to the Metro as a trip choice. A key element of the Transform 66 program includes transit service improvements both inside and outside the Beltway. The missing link between I-66 and the Metro station impedes smooth and efficient mode transfers for bus-to-metrorail trips. Another issue that arises due to the lack of direct access from I-66, and coupled with the current AM peak HOVonly restrictions for I-66 inside the Beltway, entails circuitous traffic patterns for vehicles coming from either I-495 or I-66 outside the Beltway and heading to the West Falls Church Metro station or Northern Virginia Center campus. This traffic is forced to use the I-495 / Route 7 interchange, head east on Route 7 towards Falls Church, and pass through several congested signalized intersections that are over capacity and experiencing poor level of service. These intersections on Route 7 include Idylwood Road, Pimmit Drive, Patterson Road, George C Marshall Drive/High School Entrance, and Magarity Road, as shown in Figure 2. Congested conditions at these intersections occur during AM and PM peak periods. Figure 2: Traffic Route from I-495 and Outside the Beltway to West Falls Church Metro In order to address the issue of interstate connectivity to the Metro station, the Virginia Department of Transportation is assessing the need for constructing a proposed connector ramp (slip ramp) between the I-66 eastbound Exit 66 off-ramp to Route 7 and the ramp from south-eastbound Route 7 to the eastbound I-66 collectordistributor (C-D) road that is adjacent to the Metro station parking garage. The purpose of the connector ramp would be to provide more direct access from I-66 EB to the Metro station garage, via the Route 7 ramp eastbound C-D road and ramp connector that connects to the southwest garage entrance. This connection would eliminate the circuitous indirect route that I-66 traffic must currently take to get from I-66 EB to the Metro station garage or Transform I-66 Inside the Beltway January 30, 2017 Page 0 of 7

92 JUSTIFICATION OF NEED Eastbound I-66 Exit 66 Off-Ramp at Route 7 Connector Ramp to Access West Falls Church Metro kiss-and-ride area, with the intent of creating a more efficient path to the Metro station, as well as to the adjacent Northern Virginia Center campus. The ramp connection would also help address problematic queuing and delays at the Route 7 / Haycock Road intersection. The existing intersection operates at LOS D (average delay of 63.6 seconds/vehicle) in the AM peak hour and LOS F (average delay of seconds/vehicle) in the PM peak hour. The location of the proposed ramp improvement and corresponding vehicle path are shown in Figure 3. Figure 3: Proposed Slip Ramp from Eastbound I-66 Exit 66 to Route 7 and West Falls Church Metro The conceptual plan for the proposed ramp improvement is shown in detail in Figure 4 below and entails construction of a short connector ramp, plus widening of the eastbound I-66 approach and deceleration lane for the exit ramp to Route 7 at Exit 66. The proposed connection would be fully within the existing right-of-way and would not disturb existing noise barriers or retaining walls. Benefits of the proposed improvement would include: Improved connectivity between I-66 and West Falls Church Metro / Northern Virginia Center campus Decreased traffic volumes and associated delays and queues on the exit ramp to Route 7 Reduced weaving and merging maneuvers on Route 7 heading toward Falls Church between I-66 and Haycock Road, due to reduction of traffic attempting to turn left on Haycock Road from Route 7. Improved delays and queuing at intersections along Haycock Road between Route 7 and the Dulles Connector Road overpass Potential reduction in Route 7 through traffic at congested intersections between I-495 and I-66 Provides opportunities for enhanced multimodal connectivity between upcoming Transform I-66 transit service improvements and West Falls Church Metro, which could serve as a multimodal hub Transform I-66 Inside the Beltway January 30, 2017 Page 1 of 7

93 JUSTIFICATION OF NEED Eastbound I-66 Exit 66 Off-Ramp at Route 7 Connector Ramp to Access West Falls Church Metro Figure 4: Proposed Conceptual Plan for Connector Slip Ramp Eastbound I-66 Exit 66 to Route 7 and West Falls Church Metro Conclusions / Recommendations Based on the operational/safety and connectivity issues along south-eastbound Route 7 between I-66 and Haycock Road discussed above, the proposed connection between Ramp B from eastbound I-66 and Ramp A from south-eastbound Route 7 would provide a viable design solution. The proposed modifications to the I-66 mainline cross section and the Route 7 interchange would not require additional right-of-way. The proposed connector ramp would improve connectivity for a movement that is missing from the interstate today, it would reduce the number of vehicles traveling southbound on Route 7, and would improve operational performance and safety by lessening the number of weaving maneuvers associated with vehicles coming from the I-66 / Route 7 ramp attempting to turn left at Haycock Road. This access modification shown as Ramp W above is recommended as the preferred alternative for addressing the missing interstate connection and the corresponding operational and safety issues that result. For VDOT s next steps, the development of an Interchange Modification Report (IMR) and Functional Plans are recommended, in order to gain VDOT Central Office and FHWA approval for the proposed change in access and the specific design elements of the ramp proposed improvements. Transform I-66 Inside the Beltway January 30, 2017 Page 2 of 7

94 Transform 66 Inside the Beltway Route 7 Connector Ramp Project Modified Interchange Modification Report Appendix B Framework Document for Traffic Operations and Safety Report (Interchange Modification Report Light)

95 TRANSFORM 66 INSIDE THE BELTWAY EASTBOUND I-66 EXIT 66 ROUTE 7 CONNECTOR RAMP FRAMEWORK DOCUMENT FOR TRAFFIC OPERATIONS AND SAFETY REPORT (INTERCHANGE MODIFICATION REPORT LIGHT) April 4, 2017 This document outlines the understanding between the Federal Highway Administration (FHWA) and the Virginia Department of Transportation (VDOT) for preparing a Traffic Operations and Safety Report, a.k.a. Interchange Modification Report Light (IMR Light), in lieu of a full IMR, to support the proposed connector ramp at the eastbound I-66 off-ramp at US Route 7 (Leesburg Pike) to access West Falls Church Metro Station and the UVA-VT Northern Virginia Center at Exit 66. The document summarizes the study area, assumptions, and methodology for traffic operations and safety analysis to be utilized for preparing the report. The analysis will be conducted in accordance with what was done for the Transform I-66: Inside the Beltway (ITB), Eastbound Widening Project and will follow the same methodology and assumptions documented in the framework document for the ITB Eastbound Widening project Traffic and Transportation Technical Report (TaTTR), dated October 13, PROJECT OVERVIEW The West Falls Church Metro station (herein referenced as Metro station ), located adjacent to the I-66 and Route 7 interchange in Fairfax County, currently does not have direct access from eastbound I-66. Figure 1 shows the path utilized by vehicles to get to the Metro station. Vehicles exit eastbound I-66 at Route 7, turn right and head east on Route 7 toward Falls Church, then turn left at the at Haycock Road intersection located about 1,500 feet downstream of the exit, and then turn left onto Falls Church Drive. VDOT is proposing a new connector ramp between Ramp A (eastbound Route 7 to eastbound I-66 and Metro station/uva-vt campus) and Ramp B (eastbound I-66 to eastbound Route 7 toward Falls Church) as shown in Figure 1. The proposed connector ramp will provide a direct access path for vehicles from eastbound I-66 to the Metro station and UVA-VT campus as shown blue dashed line in Figure 1. This project will be constructed along with the I-66 Inside the Beltway (ITB) Eastbound Widening project starting from 2018, and is expected to open to traffic in late Therefore, the traffic and safety analysis for this project will be built upon and consistent with TaTTR for the eastbound widening project. Potential benefits of the proposed connector ramp are as follows: Direct connectivity for vehicles to the Metro Station from eastbound I-66. By diverting vehicles off of Route 7 and Haycock Road to reach the Metro station, the operational performance on the intersections in these roadways will be improved. The diversion will improve safety by reducing the unsafe weaving maneuvers associated with vehicles existing eastbound I-66 and performing multiple lane changes in a short distance to turn left at Haycock Road.

96 FRAMEWORK DOCUMENT EASTBOUND I-66 EXIT 66 ROUTE 7 CONNECTOR RAMP: TRAFFIC OPERATIONS AND SAFETY REPORT Figure 1: Proposed Connector Ramp on Eastbound I-66 Exit 66 Transform I-66 Inside The Beltway Eastbound Widening Project April 4, 2017 Page 2 of 7

97 FRAMEWORK DOCUMENT EASTBOUND I-66 EXIT 66 ROUTE 7 CONNECTOR RAMP: TRAFFIC OPERATIONS AND SAFETY REPORT STUDY AREA FHWA guidelines indicate that the study area include all roadways within the area of influence of the project, including interchanges on either side of the project. The project study area for this ramp modification analysis will include the network that was evaluated for the I-66 ITB Eastbound Widening project and will be expanded to include additional intersections along Route 7 and Haycock Road as listed below. Figure 2 shows the project study area that includes the following: I-66 between I-495 and N Westmoreland Street I-66 and Route 7 interchange Route 7 between Pimmit Drive and Haycock Road Haycock Road between Route 7 and I-66 Intersections along Route 7 and Haycock Road including the following 1. Route 7 and Pimmit Drive 2. Route 7 and Idylwood Road 3. Route 7 and eastbound I-66 off-ramp 4. Route 7 and Haycock Road 5. Haycock Road and Falls Church Drive 6. Haycock Road and Metro entrance roadway Transform I-66 Inside The Beltway Eastbound Widening Project April 4, 2017 Page 3 of 7

98 FRAMEWORK DOCUMENT EASTBOUND I-66 EXIT 66 ROUTE 7 CONNECTOR RAMP: TRAFFIC OPERATIONS AND SAFETY REPORT Figure 2: Study Area Transform I-66 Inside The Beltway Eastbound Widening Project April 4, 2017 Page 4 of 7

99 FRAMEWORK DOCUMENT EASTBOUND I-66 EXIT 66 ROUTE 7 CONNECTOR RAMP: TRAFFIC OPERATIONS AND SAFETY REPORT ANALYSIS YEARS AND SCENARIOS This analysis years and scenarios will be kept consistent with analysis years for the I-66 ITB Eastbound Widening project TaTTR. The traffic analyses will include assessments of typical weekday AM and PM peak hour operations for the exiting year (2016) and two future years (interim year 2025 and design year 2040). The No-Build conditions will assume all improvements planned and programmed in the study area. These improvements and their anticipated opening year are listed below: 1. Transform 66 Inside the Beltway tolling, Transform 66 Inside the Beltway eastbound widening, Regional HOV/HOT requirements, Transform 66 Outside the Beltway Express Lanes project, 2021 The Build conditions will assume the construction of the connector ramp described above, in addition to all the improvements assumed in the No-Build condition. DATA COLLECTION Data collection performed during March and April 2016 as part of the Transform 66 Inside the Beltway eastbound widening project will also be utilized in this study. Available traffic counts from VDOT in the form of turning movement counts at intersections will be collected and used where available. StreetLightData has been extracted to estimate trip origin-destination (O-D) distribution patterns for the trips access to Metro Station. No other new field data collection will be conducted for this study. Consistent with the eastbound widening study, the AM and PM peak hours for analysis will be 7:15 to 8:15 AM and 5:00 to 6:00 PM respectively. TRAVEL DEMAND FORECASTING The proposed connector ramp will primarily divert traffic from the eastbound I-66 off-ramp to Route 7, the ramp terminus intersection and the eastbound left turn at the intersection of Route 7 and Haycock Road. Therefore, the impacts to travel demand and patterns are minimal and cannot be captured by traditional demand model forecasts. The forecast volumes on the connector ramp and the study area were consequently derived from previous studies, specifically the Transform 66 Inside the Beltway Eastbound Widening project. Traffic diverted to the connector ramp from other routes were estimated using existing origin-destination information available from StreetlightData in the study area. A technical memorandum developed on February 7, 2017 documents the detailed process and the estimated travel demand on the proposed ramp. The methodology and demand forecasts has been reviewed and accepted by VDOT on February 15, The methodology and forecasting memo will be included as an Appendix to the report. TRAFFIC OPERATIONAL ANALYSIS VISSIM version 8.0 will be used for a comprehensive network traffic analysis of the study area limits. As mentioned previously, the traffic and safety analysis for this project will be built upon and consistent with the TaTTR for the I-66 ITB Eastbound Widening project. Therefore, calibrated VISSIM models developed previously for the I-66 ITB Eastbound Widening study will be used in this study. No major model recalibration will be performed. However, to ensure that the model accurately replicates the conditions in the Transform I-66 Inside The Beltway Eastbound Widening Project April 4, 2017 Page 5 of 7

100 FRAMEWORK DOCUMENT EASTBOUND I-66 EXIT 66 ROUTE 7 CONNECTOR RAMP: TRAFFIC OPERATIONS AND SAFETY REPORT field, additional model tuning will be carried out following TOSAM guidelines to validate against the field conditions, especially on local arterials and intersections. The following measures of effectiveness (MOEs) will be used for the operational analysis of the roadway network under existing, no-build and future build conditions. 1. Simulated travel times from eastbound I-66 to the Metro station (seconds) 2. Simulated intersection level of service (LOS) and average control delay for six study intersections: reported by approach and by intersection (sec/vehicle, color-coded in similar fashion as the equivalent HCM delay-based LOS thresholds) 3. Simulated queue lengths on ramps and intersection approaches for six study intersections: as reported from VISSIM (average and maximum queues in feet) 4. Percent of demand served on eastbound I-66 mainline, Route 7 ramps and local intersections: simulated volume (processed volumes) divided by actual demand volume (input volumes) 5. Simulated average speed (mph) and average density (vehicles/lane/mile, color-coded similar to the equivalent Density-Based LOS Thresholds) for freeway and ramp segments. SAFETY ANALYSIS Using data provided for the study area by VDOT, crash analysis will be performed for existing conditions to reflect the most recent five-year period for which data is available. Crash analysis will include interstate mainline, ramp termini, and adjacent interchanges or intersections on crossroads within the study area, similar area as documented for traffic data collection. A combination of qualitative and quantitative analyses will be used to evaluate safety in the study area. Qualitative analyses, including documenting existing crash frequencies, severity, and predominant crash types on the I-66 mainline, ramps, and intersections on the corridor and crossroads, will be used to identify the safety issues and contributing factors to crashes for the existing condition. Crash data will be analyzed based on location, type, severity to identify existing crash patterns and safety concerns in the study area. Quantitative analyses, using AASHTO Highway Safety Manual (HSM) methodologies within the Enhanced Interchange Safety Analysis Tool (ISATe), will be used to evaluate safety with the proposed connector ramp. The predictive crash methods detailed in the HSM will be used to provide input into the roadway design process to evaluate safety for the various design options, including any recommended strategies to improve the safety performance of the proposed build condition. While the HSM models sufficiently fit the existing and proposed conditions of the freeway/interchange components of the study area to provide quantitative analysis, the HSM models are not an ideal fit for the arterial system given the complexity and would likely underestimate crash frequency for the surface streets within the study area limiting the benefit of quantitative analysis of the arterials. Therefore, the quantitative analysis using the ISATe and HSM methods will be limited to the evaluation of the freeway exit and ramps A and B for the no-build and build condition. Analysis of the arterial roadway system (Route 7, Haycock Road, Falls Church Drive) will be limited to a qualitative evaluation of expected impacts. However, while evaluation of the arterials will be qualitative, HSM concepts will still be used to provide insight into the expected benefit on the arterial system of the proposed condition. TRAFFIC OPERATIONS AND SAFETY REPORT (IMR LIGHT) OUTLINE The report will be organized in the following order: 1. Introduction 2. Responses to FHWA 8-Point Policy on Interstate Highway Access Modifications Transform I-66 Inside The Beltway Eastbound Widening Project April 4, 2017 Page 6 of 7

101 FRAMEWORK DOCUMENT EASTBOUND I-66 EXIT 66 ROUTE 7 CONNECTOR RAMP: TRAFFIC OPERATIONS AND SAFETY REPORT 3. Methodology 4. Preferred Alternative 5. Existing Traffic Operational Conditions 6. Assessment of Future Conditions (No-Build versus Build) 7. Safety and Crash Analysis Appendices A. Framework Document B. Ramp Volume Estimate and Forecasting Technical Memorandum C. Preferred Alternative Conceptual Roadway and Signing Plans D. List of Design Exceptions and Design Waivers Transform I-66 Inside The Beltway Eastbound Widening Project April 4, 2017 Page 7 of 7

102 Transform 66 Inside the Beltway Route 7 Connector Ramp Project Modified Interchange Modification Report Appendix C Estimates of Ramp Volumes Technical Memorandum

103 TRANSFORM I-66 INSIDE THE BELTWAY EASTBOUND I-66 EXIT 66 OFF-RAMP AT ROUTE 7 CONNECTOR RAMP TO ACCESS WEST FALLS CHURCH METRO AND NORTHERN VIRGINIA CENTER ESTIMATE OF RAMP TRAFFIC VOLUMES February 7, 2017 This memorandum summarizes the procedure to estimate traffic volumes that are anticipated to use the proposed connector ramp from eastbound I-66 to access West Falls Church Metro Station and Northern Virginia Center UVA-VT Campus. INTRODUCTION The West Falls Church Metro station (herein referenced as Metro station ), located adjacent to southeast to I-66 and Route 7 interchange currently does not have direct access from I-66 eastbound. Instead, vehicles must exit I-66, turn right to head south on Route 7 toward Falls Church, turn left at the signalized intersection at Haycock Road 1500 feet downstream, and then turn left onto Falls Church Drive, as shown as the yellow line in Figure 1 below. Figure 1: Existing Path (Yellow Line) and Proposed Path (Blue Line) from Eastbound I-66 Exit 66 to Route 7 and West Falls Church Metro Station

104 Estimate of Ramp Traffic Volumes on the Route 7 Connector Ramp May 15, 2017 The Virginia Department of Transportation (VDOT) is planning to build a connector ramp between Ramp A (eastbound I-66 to southbound Route 7 toward Falls Church) and Ramp B (southbound Route 7 to eastbound I-66 and Metro station/uva-vt campus). The proposed connector ramp and new direct access path are shown as the red line and blue dashed line, respectively, in Figure 1. This proposed connector ramp is anticipated to provide the following benefits: Provide direct connectivity to a multi-modal center for a movement that is missing from the interstate today Reduce the number of vehicles traveling southbound on Route 7 and turning left at Haycock Road intersection, due to elimination of the existing circuitous routing, and thereby improve the operational performance of the intersection Enhance safety due to reduction in the number of weaving maneuvers associated with vehicles coming from the I-66 / Route 7 ramp attempting to turn left at Haycock Road. EXISTING YEAR TRAFFIC ESTIMATE In order to conduct the required traffic operational analysis as part of the Interchange Modification Report (IMR), traffic volumes on the proposed connector ramp need to be developed. The conventional method is to perform travel demand modeling runs (using the MWCOG travel demand model) to forecast the traffic volumes that would shift to the proposed connector ramp. However, the regional-level MWCOG model is not sensitive enough to precisely capture the demand and routing changes for this type of localized ramp connection improvement. Therefore, an alternative approach was developed to estimate the traffic volumes that are anticipated to potentially shift to the proposed connector ramp from other route paths. The two primary movements that are included in this traffic reassignment estimation are: 1. Southbound Route 7 left-turning traffic at Haycock Road intersection, originating from eastbound I-66 (yellow line in Figure 1), and 2. A portion of traffic from eastbound I-66 that bypasses the existing parking facilities at West Falls Church Metro (due to the circuitous route or delays at Haycock Road intersection) and uses the parking facilities at the East Falls Church Metro station. Southbound Route 7 Left-Turn Traffic at Haycock Road Intersection from Eastbound I-66 Based on the existing (2016) field counts collected by the GEC study team, as well as recent traffic counts provided by VDOT Traffic Engineering at the Route 7/Haycock Road intersection, the average peak hour turning movement counts at this intersection are shown in Figure 2. Specifically, the traffic volumes for the problematic southbound Route 7 left turn movement are: 231 vehicles during AM peak hour, 417 vehicles during PM peak hour, and 3,208 vehicles daily. TECHINICAL MEMORANDUM Page 2 of 6

105 Estimate of Ramp Traffic Volumes on the Route 7 Connector Ramp May 15, 2017 Figure 2: Existing (2016) Turning Movement Counts at the Intersection of Route 7/Haycock Road The left turn traffic volumes include traffic from both eastbound and westbound I-66 and from southbound Route 7 vehicles originating from points north of the I-66 interchange. In order to determine the percentage of left turn traffic from eastbound I-66, the I-66 study team used the StreetLight Data traffic database to retrieve the detailed O-D information of this movement. StreetLight Data does not produce absolute traffic volumes; instead, it produces an index (statistical sample) that represents the proportion of traffic in the selected origin-destination pair, relative to the data that is available in the StreetLight Data system. Figure 3 below shows the zonal structure that was used to extract StreetLight Data O-D pair metrics. The O-D data consisted of consolidated daily and peak period percentage traffic average for the month of August to November 2015, and March to May 2016 (prior to WMATA s Metro SafeTrack impacts). Key zones are displayed in the figure as well. O1: Total traffic using southbound Route 7 from north of Haycock Road intersection O2: Eastbound I-66 off-ramp to Route 7 traffic The proposed connector ramp is anticipated to re-route the I-66 EB trips using the left-turn lane at Route 7/Haycock Road to reach either one, or a combination, of the following destinations: D1: Turn left onto Falls Church Road towards a. West Falls Church Metro parking facilities b. Northern Virginia Center UVA-VT Campus c. George Mason High School D2: Travel further (pass-through) on Haycock Road towards Great Falls Street (VA 694) to avoid Route 7 intersections Using the information from StreetLight Data, we estimated the proportion of traffic from eastbound I-66 to the destinations listed above, which would shift to the new connector ramp and take the direct access path (shown as the blue dashed line in Figure 1). TECHINICAL MEMORANDUM Page 3 of 6