Estimating Work Zone Performance Measures on Signalized Arterial Arterials

Transcription

1 Estimating Work Zone Performance Measures on Signalized Arterial Arterials Minneapolis, MN Prepared By: Alliant Engineering, Inc. 233 Park Avenue South, Suite 300 Minneapolis, MN Prepared For: Minnesota Department of Transportation Final Report May 30, 2016

2 Table of Contents Executive Summary... iii 1 Introduction System Overview Performance Measures Literature Search MnDOT Current Practice Performance Measures for this Project Corridor Selection Construction Activities on and around Highway Implementation Monitoring Baseline Conditions Monthly Reports I-394 Westbound Lane Closure I-394 Eastbound Closure Performance Measure Comparison Lessons Learned Success Stories Problems Encountered Best Practices Related to SMART-Signal Monitoring Work Zone Performance Measures on Future Projects APPENDIX i Alliant

3 List of Tables Table Urban Street Level of Service Criteria... 4 Table Baseline Travel Times Table Baseline Arterial Level of Service Table Travel Times during Westbound I-394 Closure Table Arterial Level of Service during Westbound I-394 Closure Table Travel Times during Eastbound I-394 Closure Table Arterial Level of Service during Eastbound I-394 Closure List of Figures Figure 4.1 Project Location Map... 6 ii Alliant

4 Executive Summary Work zones can cause significant traffic congestion and safety impacts. Work zone performance measures help agencies improve their understanding of how their decisions during planning, design, and construction affect work zone safety and mobility. Performance measures on signalized arterial corridors are difficult to measure because of the variability caused by traffic signal operations. New traffic signal technologies are emerging that collect and utilize high resolution data to produce performance measures on signalized arterials. The basic operational concept is to use a High Resolution Monitoring System (HRMS) to monitor work zone operations on a signalized arterial corridor and document performance measures such as delays and travel time. When specific performance measure thresholds are reached (such as a 15 minute increase in travel time delay), the Traffic Engineer may choose to take action to mitigate the delay, such as adjusting signal timing or implementing other traffic control measures to improve operations. SMART-Signal is one example of the High Resolution Monitoring System described above. SMART-Signal has been deployed by MnDOT at a number of signalized intersections, primarily within the Metro District. This project utilized SMART-Signal to monitor work zone performance on TH 55 during the 2015 construction season. Performance Measures and Thresholds Based on the literature search and MnDOT practice, it was determined to utilize increase in travel time delay as the primary performance measure. Based on MnDOT practice, the threshold to signify significant congestion is an increase in the travel time delay by 15 minutes for a corridor longer than one mile. Another performance measure that will be considered for this project is Arterial Level of Service (LOS). The Highway Capacity Manual provides LOS criteria based on a percentage of the free flow speed. A drop in arterial operations below LOS E, or a drop of two letter grades, will be considered indicators of congestion. Corridor Selection After review of several potential candidates, the Highway 55 corridor was selected. The corridor extended from Theodore Wirth Parkway to Arrowhead Drive, and included 26 intersections. Although no substantial physical construction was planned on Highway 55, Highway 55 would serve as a diversion route for two nearby construction projects: I-494 and I-394. System Implementation and Baseline Data The implementation of SMART-Signal included installation of a device in each cabinet (Adaptitrol) which allows SMART-Signal to monitor intersection operations. The communication system utilized two strands of unused fiber from MnDOT that connected each of the intersections back to the Regional Traffic Management Center (RTMC). SMART-Signal staff also worked closely with Alliant staff to further develop the software interface (imeasure) to provide greater flexibility in data manipulation and reporting. The system was up and running at all 26 intersections by the end of March A baseline report was created prior to construction beginning on the corridor. Volumes, Intersection Delay and LOS, maximum queue length, Arterial LOS, and Travel Time were documented for a typical weekday, Saturday, and Sunday. iii Alliant

5 Monitoring of Work Zone Events on I-394 The Alliant Team monitored traffic conditions on a weekly basis, and prepared monthly reports summarizing the results. In general, the existing signal timing plans on TH 55 were able to effectively handle changes in traffic volumes, and only minor changes in travel time and delay were noticed. The I-394 reconstruction project had two significant events that were analyzed in more detail. For two weeks in July, construction occurred on the westbound lanes of I-394. I-394 westbound traffic was placed in the HOV/HOT lanes between downtown and TH 100. The eastbound general purpose lanes remained open, but included all eastbound traffic, including HOV. For two weeks in early August, construction occurred on the eastbound lanes of I-394. I-394 eastbound traffic was placed in the HOV/HOT lanes between downtown and TH 100. The westbound general purpose lanes remained open, but included all westbound traffic, including HOV. The SMART-Signal system was utilized to develop travel time and travel speed estimations for the peak periods. Manual travel times were also conducted by Alliant staff to verify the performance of the system. For the two events on I-394, data on TH 55 was gathered and compared to the two performance measure thresholds: Increase in travel time delay by more than 15 minutes A significant drop in arterial LOS (from LOS E to LOS F, or a drop of two letter grades) During the Westbound I-394 lane closure, the increase in travel time delay during both peak periods was less than 15 minutes in both directions. Therefore, the threshold for enhanced mitigation measures was not reached. The arterial LOS remained LOS D or better, which also did not reach the threshold for enhanced mitigation measures. However, specific segments reached LOS F, which could signify the need for additional mitigation, including modification of the signal timing plan. The Eastbound I-394 lane closure provided similar results. While travel time delay did increase to 13 minutes, it fell short of the 15 minute threshold. Similarly, the overall arterial operations remained at LOS D or better. However, specific segments dropped to LOS F, which could signify the need for mitigation measures. Lessons Learned SMART-Signal, and its performance measure software, imeasure, is a powerful tool that can document travel time and delay. The system s travel time estimation algorithm is accurate under most conditions. Manually collected travel time data verified the accuracy of the system as part of this project. Both travel times and arterial level of service (travel speed) are known performance measures that can quantify corridor performance and impacts. In particular, arterial level of service can not only identify an impact, but can also provide an understanding of the level of impact when compared to normal conditions. Travel time estimation on signalized arterial corridors is more complex than on freeways. The signal delay adds in variability under normal conditions. Travel times should be reported as a range to account for this variability. Changes in the 85 th percentile travel times should be used to indicate increased congestion. The Highway 55 corridor proved to be capable of handling changes in traffic volumes within its normal signal operations plan under most conditions. The imeasure system provided validation that the corridor was operating under acceptable parameters. iv Alliant

6 Problems Encountered The availability and consistency of data is extremely important. Communications between traffic signals and the data server must be maintained at all times. If communications are lost, data is not available to calculate travel times or to compare other performance measures. The signalized arterial corridor cannot include intersections controlled as all-way stops (either signed or if signals are on red flash). The algorithms to calculate travel times, intersection delay, and queuing do not work under this scenario. Overall, the imeasure systems appears to be accurate when measuring performance measures. However, there were some instances (bad weather, incidents blocking lanes) that caused high levels of queuing and congestion. Under these circumstances, imeasure underestimated the level of congestion (travel times, queuing, delays). Best Practices The system should be checked frequently to confirm that all traffic signal equipment and communications are operating properly. When problems are encountered, the issue should be rectified as soon as possible, or at least noted so that the reason for missing data is understood. On future projects, data could be used to modify the time-of-day signal timing program to better address changes in traffic flows caused by construction. Under extreme circumstances with long durations, this data could also be used to develop new signal timing plan. The system could be used to validate traffic complaints (both for corridors under construction and normal corridors). When a complaint is received, information such as delay, queuing, and travel time can be reviewed from the time period in question to determine if a problem existed. Based on the experience of this project, the group discussed developing a methodology that could be used on projects in the future. The steps identified in Section 7.4 provide a high level summary of a process that could be followed. v Alliant

7 1 Introduction Work zones can cause significant traffic congestion and safety impacts. Agencies strive to manage these impacts as best possible to meet the needs of its customers, complete the project effectively, and support regional mobility and the economy. Agencies can systematically assess work zone impacts by utilizing performance measures. Work zone performance measures help agencies improve their understanding of how their decisions during planning, design, and construction affect work zone safety and mobility, and thus can help improve how they make decisions for future work zones. During a project, performance measures can be used to actively manage traffic operations, and to provide travel time and delay information to the public. Two frequently used performance measures for traffic operations are queue lengths and travel time delay. Accurate measurements of travel time delay can also be shared with the traveling public as a travel demand management tool, allowing the driver to choose their route based on current travel time and delay information. Performance measures on signalized arterial corridors are difficult to measure because of the variability caused by traffic signal operations. Typical methods used on freeways to measure travel time delay include estimating travel time from manually measured queue lengths or travel time runs. Another method utilizes spot sensors to estimate speed and queue length. While these methods work well for freeways, their accuracy and effectiveness on signalized arterials is limited, because they cannot account for the signal delay. Other methods that track vehicles through a system, such as Bluetooth or Sensys, are expensive to implement as a work zone management tool, and still have issues with accuracy. Traffic signal technologies are emerging that may provide additional information related to work zones. Technologies that are being developed include systems that collect and utilize high resolution data to produce performance measures on signalized arterials. The basic operational concept is to use a High Resolution Monitoring System (HRMS) to monitor work zone operations on a signalized arterial corridor and document performance measures such as change in volume, queues, saturation flow rates, delays, and travel times. When specific performance measure thresholds are reached (such as 10 minute increase in delay or travel time), data from the HRMS will be utilized to identify the delay, and to adjust signal timing or identify other traffic control measures (such as closing specific turn movements or intersections) to improve operations. 2 System Overview A system that utilizes a High Resolution Monitoring System (HRMS) to monitor work zone performance will include the following features: Controller Interface - Collects controller and detector data from each intersection directly from the controller. If the controller is not equipped to permit the collection and communication of requisite data, a NEMA-compliant retrofit kit for 170/2070, TS1 and TS2 type controllers is installed. It is a plug and play device that easily slides into the controller cabinet. The kit permits the collection of data from all detector types including loop, video and radar devices and from all manufactures of controller. Communications - The data from each traffic signal is retrieved to a database server. The preferred communications method is over fiber optic cable. However, cell phone communications can be used if hard-wire connections are not available. 1 Alliant

8 Performance Measure Analysis The HRMS would include an algorithm that uses the actual traffic data collected to calculate an algorithmic model of traffic behavior, queue lengths, and travel times. The software also calculates other performance measures such as saturation flow rates and intersection delay Software and User Interface The HRMS includes software and a user interface that can be used to create data collection and performance measure reports. Additional Detection The HRMS requires that the signal system has mainline detection in advance of the intersection. If this detection is not present, additional temporary detection would need to be installed. SMART-Signal is one example of the High Resolution Monitoring System described above. SMART-Signal has been deployed by MnDOT at a number of signalized intersections, primarily within the Metro District. It is used to monitor performance on signalized arterials, and to gather data used for signal optimization. SMART Signal Technologies, Inc. helps improve traffic on signalized arterial corridors by offering a set of technologies for the Systematic Monitoring of Arterial Road Traffic that permits calculation of accurate queue lengths and travel times using existing installed infrastructure augmented by the company's proprietary Queue Length Processing (QLP) algorithms to provide Real Time Performance Measures. SMART Signal technology has been implemented on several MnDOT corridors and has been found to be a relatively reliable source for traffic volume, vehicle queues, and arterial travel time information. Further software enhancements have created tools that can provide a historic model of system performance, and tools that can provide traffic engineers with information that can assist in identifying and diagnosing problems in signal operations. A Systems Engineering analysis, including a Concept of Operations, was developed for the project and is included in the appendix. 3 Performance Measures 3.1 Literature Search In the FHWA s A Primer on Work Zone Safety and Mobility Performance Measurement, the three main categories of work zone performance measures are: Exposure measurements: the amount of time, work activity periods, roadway space, and/or vehicle travel that a work zone affects. Safety measurements: how a crash risk has changed for individual motorist and/or traveling public. Mobility measurements (traffic operations): how travel mobility has been affected for motorists (and other types of travelers). (FHWA, 2011) The FHWA s Primer also notes that monitoring urban arterial roadways are more complex than freeway work zones, due to delays from signals and other traffic control devices. It suggests that local agencies to establish freeway measures before moving onto arterial work zones. (FHWA, 2011). This project will focus on the third bullet above, documenting how mobility has been affected by construction activities. Technical Memorandum No. 1, Current Policies and Practices, is included in the appendix. The Technical Memorandum summarizes both the national literature search and a summary of MnDOT Current Practice. 2 Alliant

9 3.2 MnDOT Current Practice MnDOT has primarily focused on freeway elements when evaluating performance measures in work zones. The two most frequently utilized measures are change in traffic volume, and travel times (added delay). MnDOT has summarized performance measures (travel times) on a frequent basis on other construction projects. MnDOT uses system detector data to monitor traffic volumes on signalized corridors. They have also conducted manual travel time runs. MnDOT Traffic uses FREEVAL and QUICKZONE to analyze freeways, and Synchro for arterials. Another challenge in estimating work zone impacts is determining the amount of traffic that will divert away from work zone before it happens. Simplistic methods for estimating traffic exist, such as the 1/3-1/3-1/3 rule (1/3 of traffic stays on the route under construction, 1/3 diverts to the detour route or other logical route, 1/3 changes time or pattern completely). However, MnDOT typically relies on the regional travel demand model to estimate diversion levels. MnDOT typically prepares a Transportation Management Plan that establishes threshold to trigger enhanced mitigation efforts. Some mitigation occurs during design. MnDOT uses the following thresholds for both arterials and freeways: Less than 1 mile 10 minutes added delay More than 1 mile 15 minutes added delay MnDOT s signal operations group monitors corridors that are under construction by utilizing cameras (if available) to frequently monitor operations. They also rely on field reviews, and calls received from the public. On occasion, new timing plans have been developed, if construction activities will impact the corridor is a consistent manner for an extended period of time. Signal coordination is maintained by manually synching local clocks if interconnect is not available. Where possible, the TMP should address and consider mitigation measures ahead of time. This was done successfully on the recent TH 61 project, where temporary improvements such as dual lefts, free rights, and turn lane extensions were added to the traffic control plans. Mitigation measures can be identified through a TMP, or with institutional knowledge of system. 3.3 Performance Measures for this Project Based on the literature search and MnDOT practice, it was determined to utilize travel time and change in traffic volume as the two primary performance measures. Because of the capabilities of the SMART- Signal system, it was also determined to monitor and document queue lengths and intersection delay. Because travel time on a signalized corridor can be variable based on how a vehicle is impacted by signal delay, the travel time will be reported as a range based on best case/worst case travel times, estimated by the 15 th and 85 th percentiles. The threshold to signify significant congestion or delay would be an increase in the 85 th percentile travel time by 15 minutes, if the corridor is longer than one mile. 3 Alliant

10 Another performance measure that could be considered is Arterial Level of Service (LOS). The Highway Capacity Manual, Chapter 16/Urban Street Facilities, provides level of service criteria based on a percentage of the free flow speed. Table below summarizes the level of service criteria as a percentage of Base Free Flow Speed. The table also includes values for free flow speeds of 55 mph and 50 mph, which are found on the TH 55 corridor. These criteria can measure a drop in level of service that may trigger enhanced mitigation efforts, and could also provide guidance regarding the magnitude of the mitigation effort. In an urban area, the LOS D/E boundary is typically considered the indicator of congestion on arterial signalized corridor. Work zone activities resulting in a decrease in performance from LOS C to LOS D may require little or no action. However, work zone activities resulting in a decrease from LOS to LOS F may require enhanced mitigation efforts. Table Urban Street Level of Service Criteria 4 Alliant

11 4 Corridor Selection The locations selected for implementing the Estimating Work Zone Performance on Signalized Arterials system would be determined by input from Signal Operations and Work Zone Management staff. Ideal corridor locations include two scenarios: Scenario 1: Signalized arterial under construction (work zone impacts available capacity and operations on roadway) Scenario 2: Signalized arterial impacted by adjacent construction (traffic volumes increase because route used as official or unofficial detour route) In addition, because of the specific constraints of this project, construction needed to occur in 2015 and last at least two months, preferably longer. The project budget assumed one corridor of 10 intersections, or two corridors of five intersections. After review of several potential candidates, the Highway 55 corridor was selected. The key characteristics of Highway 55 are listed below: The corridor extends from Theodore Wirth Parkway on the east to Arrowhead drive on the west (approximately 13 miles). See Figure 4.1 The corridor included 26 intersections which was larger than originally planned. However, 10 of the intersections were already equipped with the SMART-Signal equipment, and it was determined to move forward with this corridor. There will not be substantial physical construction on Highway 55, except for a few short-term projects. However, Highway 55 would serve as a diversion route for two nearby construction projects: o I-494 will be under construction between I-94 and I-394, and Highway 55 would serve as an alternate route. o I-394 will be under construction between downtown and TH 100, and Highway 55 would be posted as an alternate route for several major closures. 5 Alliant

12 Figure 4.1 Project Location Map 6 Alliant

13 4.1 Construction Activities on and around Highway 55 The table below summarizes all of the construction projects that could affect traffic operations on Highway 55 during The project team tracked the construction projects to help understand the impacts. Project Location Number TH 55 I494 to Plymouth Blvd I-494 in Plymouth TH 100 in Golden Valley at TH TH 100 in St. Louis Park between Cedar and 36 th Street I-394 between I-94 and TH 100 Vicksburg Lane North of Rockford Road Start/End Dates Description of Impacts / Website 7/06/15-8/23/15 Add 3 rd Lane WB, Lane Closures mndot.gov/metro/projects/hwy55plymouth/ 4/13/15-11/15/15 Repair pavement, bridge decks and ramps, and add a third lane between Hwy 55 and the I-94/694 interchange mndot.gov/metro/projects/i494plymouth/ August-October Extend northbound exit ramp to Hwy 55 and turn lanes; Ramp and shoulder closures April-November Interchange reconstruction; Lane Closures, full weekend closures, detours mndot.gov/metro/projects/hwy100slp/ June-September Resurface I-394 and frontage roads; reconstruct Lyndale Ave bridge. Major impacts, two weeks in each direction (Jul-Aug); weekend and night impacts all summer mndot.gov/metro/projects/i394minneapolis/ 2015 Reconstruction with Closures Revere Lane 2015 Mill and Overlay of neighborhood south of TH 55 5 Implementation The SMART-Signal system was set up to be completely independent of the traffic signal control system. With the assistance of MnDOT staff, the project team implemented the SMART-Signal system on the TH 55 corridor. The implementation included installation of a device in each cabinet (Adaptitrol) which allows SMART-Signal to monitor intersection operations. The communication system utilized two strands of unused fiber from MnDOT that connected each of the intersections back to the Regional Traffic Management Center (RTMC), relaying information to a special SMART-Signal server housed at the RTMC. SMART-Signal staff also worked closely with Alliant staff to further develop the software interface (imeasure) to provide greater flexibility in data manipulation and reporting. The system was up and running at all 26 intersections by the end of March Alliant

14 6 Monitoring 6.1 Baseline Conditions A baseline report was created prior to construction beginning on the corridor. The time period from 3/28/15 to 4/03/15 was chosen for the baseline week. The following bullets summarize the baseline condition: Volumes: Overall, traffic patterns show that volumes reflect commuter-based traffic, with peaks in the AM and PM peak hours. Among the volume count locations, volumes are highest west of I-494, peaking at over 600 vehicles per 15-minute interval in the AM peak. Weekend traffic varies by location and time of day, but generally, Saturday volumes are higher than Sunday. Intersection Delay and Intersection LOS: In analyzing all approaches, most of the intersections operate an acceptable LOS. In analyzing minor approaches, delays are much more significant along the corridor. Heaviest delays are seen in the AM and PM peak periods, with the worst delays shown between Highway 100 and South Shore Drive, as well as Fernbrook Lane to Sioux Drive. The worst interchanges operate mostly around LOS E/LOS F during the peak periods. Maximum Queue Length: Overall, most intersections along the TH-55 corridor have an acceptable queue length at the eastbound and westbound approaches. During the AM peak period, Niagara Lane/Plymouth Boulevard experiences heavier queuing eastbound, at times pushing past the storage of the turn pockets. Peony Lane also sees longer queues in the AM, with some queues that may block turn lane pockets. In the PM peak period, heavy queuing westbound is observed at the TH-494 East Ramps and at Fernbrook Lane. Storage for westbound Fernbrook is limited due to its close proximity to the TH-494 West Ramp, which is about 725 feet away. Additionally, Sioux Drive westbound in the PM peak experiences heavier queuing, with some queue lengths extending beyond the turn lane pockets. Average Speeds/Arterial LOS: Overall, the corridor operates at an acceptable LOS in both the AM and PM peak hours, ranging in speeds of about mph (LOS B/C). Heavier delays are seen westbound between Theodore Wirth Parkway and TH-100 (east end of corridor) in both the AM and PM peak, where the average speeds are about 26 mph (LOS C/D). Travel Time: Eastbound travel time for the full corridor in the AM peak ranges from minutes, while the PM peak ranges from minutes. In the westbound direction, corridor travel time in the AM is minutes, while the PM is nearly minutes. Typical delay from traffic signals ranges from 5-12 minutes based on a free flow travel time of 14 minutes. 6.2 Monthly Reports The Alliant Team monitored traffic conditions on a weekly basis, and prepared monthly reports summarizing the results. In general, the existing signal timing plans were able to handle changes in traffic volumes, and only minor changes in travel time and delay were noticed. This was not unexpected, since most of the construction impacts did not directly affect conditions on TH 55. However, the I-394 reconstruction project had two significant events that were analyzed in more detail, since the activities greatly impacted operations on TH 55. Between 7/13 and 7/27, construction occurred on the westbound lanes of I-394. I-394 westbound traffic was placed in the HOV/HOT lanes between downtown and TH 100. The eastbound general purpose lanes remained open, but included all eastbound traffic, including HOV. Between 8/03 and 8/14, construction occurred on the eastbound lanes of I-394. I-394 eastbound traffic was placed in the HOV/HOT lanes between downtown and TH 100. The westbound general purpose lanes remained open, but included all westbound traffic, including HOV. All of the monthly reports are included in the appendix. 8 Alliant

15 6.3 I-394 Westbound Lane Closure Volume, average speed, and travel time data was collected for the week of July 13, 2015 from the imeasure system and was summarized in tables and charts. imeasure data indicated that westbound traffic volumes doubled along the east end of the TH 55 corridor. imeasure reported slightly higher travel time data than baseline week travel time data. imeasure reported little change in arterial travel speed, and no change in LOS. Alliant also conducted field observations and manual travel time runs to provide additional data, and to verify how well SMART-Signal addressed congested conditions. The SMART-Signal travel time data compared well with field collected data, except for the westbound direction in the PM peak. For the WB direction in the PM peak, SMART-Signal was found to have underreported travel times during very congested conditions, when compared to actual data collected in the field. Alliant conducted field observations along the TH 55 corridor during the closure. All of the observations below reflect PM Peak traffic conditions. o Getting out of downtown Minneapolis was very difficult for westbound I-394 traffic as it was forced down to one lane in order to get all of this traffic onto the HOV lanes. o Heavy westbound TH 55 congestion from Penn Ave to Bryant Ave. Penn Ave was not clearing the queue and created a pinch point. o Heavy westbound TH 55 congestion from Winnetka Ave to Douglas Dr. o Heavy westbound TH 55 congestion from Revere Lane to east of TH 169. o Heavy westbound TH 55 congestion from Fernbrook Lane to County Road 6 due in part to a weaving area just west of Northwest Blvd. The group discussed possible mitigation measures that could have been implemented. The most effective mitigation would be to adjust the time-of-day pattern to better fit the changes to the traffic volume profile caused by the traffic diversion. Adjusting the time of day pattern could be accomplished with minimal effort, and would still rely on timing plans previously created. Adjusting the time of day plan could improve traffic flow by beginning a higher cycle / higher volume traffic signal plan sooner to accommodate higher traffic volumes anticipated by the detour. 6.4 I-394 Eastbound Closure Volume, average speed, and travel time data was collected for the weeks of August 3-14, 2015 from the imeasure system and was summarized in tables and charts. Eastbound imeasure data reported up to a 50% increase in traffic volumes around the I-494 area of the TH 55 corridor during the Mid-day period, and doubled in the Mid-Day period and increased by 50% in the AM and PM periods on the east side of the TH 55 corridor. imeasure reported up to 60% volume increases on northbound ramps from TH 100 onto TH 55 and southbound ramps from TH 55 onto TH 169. imeasure reported slightly higher travel time data than baseline week travel time data. No differences were found in the first and second weeks of the closure in terms of volumes and travel times. imeasure reported a drop in Arterial LOS in the westbound direction on Segments 2 and 3 from LOS C to LOS E/F. Travel times were collected during the AM and PM peak periods. Seven runs were conducted in each direction. The field collected travel times fell within the ranges reported by imeasure, verifying the accuracy of system. 9 Alliant

16 6.5 Performance Measure Comparison The imeasure system was utilized to develop travel time and travel speed estimations for the peak periods. imeasure allows the user to configure how many travel time probe vehicles are used to estimate performance measures. The probe vehicle represents a specific vehicle leaving the first signalized intersection in the system at a given time. More probe vehicles provide better coverage of potential delays and variations in travel times. However, a large number of probe vehicles results in slower performance of the imeasure system and requires more data manipulation. For this project, one probe vehicle for every 50 actual vehicles was found to provide the desired information. Manual travel times were also conducted by Alliant staff to verify the performance of the imeasure system, and to provide more information during the two larger construction events caused by closures on I-394. The following tables provide a summary of this information: Table Baseline Travel Times Table Baseline Arterial Level of Service Table Travel Times during Westbound I-394 Lane Closure Table Arterial Level of Service during Wesbound I-394 Lane Closure Table Travel Times during Eastbound I-394 Lane Closure Table Travel Times during Eastbound I-394 Lane Closure A summary of the travel time information is included in the following bullets: Baseline travel times on the corridor range from minutes. During the Westbound I-394 Lane Closure: o Travel Times - AM Peak - imeasure reported a range of travel times from minutes. All manual travel time runs fell within this range, confirming accuracy. PM Peak - imeasure reported a range of travel times from minutes, basically no change from the baseline. Manually collected travel times general range of minutes, much higher than reported by imeasure. The manually collected travel times indicates an 11 minute increase in delay, which did not reach the criteria for enhanced mitigation measures of 15 minutes. o Arterial Level of Service - AM Peak imeasure reported little to no change in arterial LOS. This was confirmed by field data. PM Peak imeasure reported no change in arterial LOS in either direction. However, field data indicates that overall performance on the corridor dropped from LOS C to LOS D. Segments 2 and 3 dropped to LOS F. During the Eastbound I-394 Lane Closure: o Travel Times - AM Peak - imeasure reported a range of travel times from minutes. All manual travel time runs fell within this range, confirming accuracy. PM Peak - imeasure reported a range of travel times from minutes. All manually collected travel time runs fell into this range. The increased delay over baseline was 13 minutes, which did not reach the criteria for enhanced mitigation measures of 15 minutes. o Arterial Level of Service - AM Peak imeasure reported a drop in performance from LOS C to LOS F in Segment 2. This was confirmed by field data. PM Peak imeasure reported a drop in overall WB corridor performance from LOS C to LOS D. For Segments 2 and 3, performance dropped to LOS F. This was confirmed by field data. 10 Alliant

17 Table Baseline Travel Times Notes: Low Range and High Range based on 15 th and 85 th percentile data Data Sampling Parameters: Average of every 100 th vehicle within time period Days Sampled: Baseline week, Wednesday 4/1/15 thru Thursday 4/2/15 11 Alliant

18 Table Baseline Travel Speeds Notes: Average Speed is calculated based on Travel Time Data Low Range and High Range based on 15 th and 85 th percentile data Data Sampling Parameters: Average of every 100 th vehicle within time period Days Sampled: Baseline week, Wednesday 4/1/15 thru Thursday 4/2/15 12 Alliant

19 Table Travel Times during Westbound I-394 Closure AM Peak PM Peak Segment Eastbound imeasure Range Field Run (Start Time) imeasure Range Field Run (Start Time) Low High 07:25 07:26 08:18 08:18 - Low High 04:31 04:34 04:35 04:39 05:37 05:40 05:47 1 TH-55: Arrowhead Drive to I-494 West Ramp 9:21 10:49 11:04 10:19 07:50 10:12-9:05 11:03 08:33 11:04 10:17 08:53 08:39 10:00 08:27 2 TH-55: I-494 West Ramp to Revere Lane 4:39 5:53 05:27 03:37 05:20 05:00-5:23 6:53 07:26 08:54 04:46 09:16 04:31 05:45 04:36 3 TH-55: Revere Lane to TH-100 4:43 5:39 04:21 05:29 06:05 05:09-5:03 6:21 07:58 08:35 05:01 22:05 05:26 04:51 03:48 4 TH-55: TH-100 to Theodore Wirth Parkway 1:43 2:34 01:18 01:16 01:55 01:25-1:42 2:07 01:16 01:21 01:15 01:22 01:14 01:14 00:00 TOTAL TH-55: Arrowhead Drive to Theodore Wirth Parkway 20:27 24:57 22:10 20:41 21:10 21:46-21:14 26:26 25:13 29:54 21:19 41:36 19:50 21:50 16:51 AM Peak PM Peak Segment Westbound imeasure Range Field Run (Start Time) imeasure Range Field Run (Start Time) Low High 07:00 07:00 07:48 07:49 08:41 Low High 04:00 04:00 04:00 04:00 04:58 04:59 05:05 4 TH-55: Theodore Wirth Parkway to TH-100 2:11 2:41 01:22 02:03 02:36 02:19 01:33 1:57 3:10 02:00 02:05 05:31 02:17 02:31 02:12 02:40 3 TH-55: TH-100 to Revere Lane 5:13 6:38 05:13 05:20 07:39 07:39 05:09 5:11 6:23 06:03 06:14 08:16 03:50 11:07 09:29 09:58 2 TH-55: Revere Lane to I-494 West Ramp 5:31 6:58 04:48 04:52 05:24 05:17 06:20 5:14 6:09 12:11 13:19 10:12 07:09 13:05 15:22 16:59 1 TH-55: I-494 West Ramp to Arrowhead Drive 9:08 10:39 10:34 10:16 09:59 09:48 08:26 9:12 10:09 08:03 09:28 09:09 08:36 09:18 09:52 09:38 TOTAL TH-55: Theodore Wirth Parkway to Arrowhead Drive 22:04 26:57 21:57 22:31 25:38 25:03 21:28 21:35 25:52 28:17 31:06 33:08 21:52 36:01 36:55 39:15 Notes: Field travel time data was collected during July 14th thru July 16th, 2015 and July 23, 2015 Data was unavailable for Segment 1 Westbound, baselines were used to estimate Segment 1 Westbound ranges 13 Alliant

20 Table Arterial Level of Service during Westbound I-394 Closure Segment Low Range Speed High Range Speed Low Range Speed High Range Speed Baseline Current % Change Baseline Current % Change Baseline Current % Change Baseline Current % Change 1 TH-55: Arrowhead Drive to I-494 West Ramp 31, % % % % 2 TH-55: I-494 West Ramp to Revere Lane 16, % % % % 3 TH-55: Revere Lane to TH , % % % % 4 TH-55: TH-100 to Theodore Wirth Parkway 5, % % % % TOTAL TH-55: Arrowhead Drive to Theodore Wirth Parkway 69, % % % % Segment Eastbound Westbound Distance (ft) Distance (ft) Base FFS (mph) Base FFS (mph) AM Peak Hour 7:30 AM-8:30 AM AM Peak Hour 7:30 AM-8:30 AM PM Peak Hour 4:30 PM-5:30 PM PM Peak Hour 4:30 PM-5:30 PM Low Range Speed High Range Speed Low Range Speed High Range Speed Baseline Current % Change Baseline Current % Change Baseline Current % Change Baseline Current % Change 4 TH-55: Theodore Wirth Parkway to TH-100 5, % % % % 3 TH-55: TH-100 to Revere Lane 16, % % % % 2 TH-55: Revere Lane to I-494 West Ramp 16, % % % % 1 TH-55: I-494 West Ramp to Arrowhead Drive 31, N/A N/A N/A N/A TOTAL TH-55: Theodore Wirth Parkway to Arrowhead Drive 69, N/A N/A N/A N/A NOTES: Vehicle sampling was for ever 50th vehicle over one-hour peak period Baseline data was repulled for every 50th vehicle over one-hour period (was reported as every 100th vehicle in Baseline Memo) Baseline data was pulled only for Wednesday, April 1st and Thursday, April 2nd Data was unavailable for Segment 1 Westbound, Baseline values were utilized 14 Alliant

21 Table Travel Times During Eastbound I-394 Closure WEEK OF 8/03/15 WEEK OF 8/10/15 Notes: Low Range and High Range based on 15 th and 85 th percentile data Data Sampling Parameters: Average of every 50th vehicle within a one-hour time period Data was unavailable for Segment 1 Westbound, baselines were used to estimate Segment 1 Westbound ranges Table Estimating Work Zone Performance AM Peak PM Peak Segment Eastbound imeasure Range Field Run (Start Time) imeasure Range Field Run (Start Time) Low High 07:26 07:26 08:18 08:18 - Low High 04:27 04:43 05: TH-55: Arrowhead Drive to I-494 West Ramp 9:19 14:41 09:16 11:45 09:21 10:07-9:48 12:40 09:53 09:10 09: TH-55: I-494 West Ramp to Revere Lane 4:37 6:21 04:45 03:17 04:15 04:52-5:21 6:52 05:04 05:03 05: TH-55: Revere Lane to TH-100 4:36 5:35 05:59 03:20 07:08 05:13-4:31 5:22 05:53 06:04 08: TH-55: TH-100 to Theodore Wirth Parkway 1:42 2:30 03:09 02:35 03:20 02:39-1:43 2:31 02:57 01:16 06: TOTAL TH-55: Arrowhead Drive to Theodore Wirth Parkway 20:17 29:07 23:09 20:57 24:04 22:51-21:25 27:27 23:47 21:33 29: AM Peak PM Peak Segment Westbound imeasure Range Field Run (Start Time) imeasure Range Field Run (Start Time) Low High 07:00 07:00 07:51 07:51 08:43 Low High 04:00 04:00 04:54 05: TH-55: Theodore Wirth Parkway to TH-100 1:53 2:33 02:10 02:38 02:26 02:20 01:37 2:09 3:38 01:33 02:31 02:19 02: TH-55: TH-100 to Revere Lane 4:57 6:01 05:31 05:30 06:10 04:47 05:14 4:55 12:23 05:10 04:03 06:16 09: TH-55: Revere Lane to I-494 West Ramp 5:23 11:41 04:15 04:00 04:21 05:01 04:41 5:18 10:34 07:14 06:03 06:35 06: TH-55: I-494 West Ramp to Arrowhead Drive 9:03 10:43 09:36 09:56 09:54 10:13 07:42 9:11 10:20 08:38 13:05 07:46 09: TOTAL TH-55: Theodore Wirth Parkway to Arrowhead Drive 21:16 30:59 21:32 22:04 22:51 22:21 19:14 21:34 36:56 22:35 25:42 22:56 28: AM Peak PM Peak Segment Eastbound imeasure Range Field Run (Start Time) imeasure Range Field Run (Start Time) Low High 7:25 AM 07:26 8:20 AM 08:18 - Low High 4:24 PM 4:28 PM 5:20 PM 5:27 PM TH-55: Arrowhead Drive to I-494 West Ramp 9:35 11:00 13:11 12:01 07:46 07:37-9:18 11:17 09:59 09:45 08:58 10: TH-55: I-494 West Ramp to Revere Lane 4:33 5:56 04:11 04:20 05:31 05:25-5:28 6:58 08:30 05:02 04:52 04: TH-55: Revere Lane to TH-100 4:21 5:21 08:09 06:09 08:19 05:32-4:28 5:17 08:17 08:02 08:10 04: TH-55: TH-100 to Theodore Wirth Parkway 1:42 2:27 01:38 02:38 03:29 02:42-1:43 2:41 01:25 01:17 04:27 01: TOTAL TH-55: Arrowhead Drive to Theodore Wirth Parkway 20:13 24:44 27:09 25:08 25:05 21:16-20:58 26:14 28:11 24:06 26:27 21: AM Peak PM Peak Segment Westbound imeasure Range Field Run (Start Time) imeasure Range Field Run (Start Time) Low High 7:00 AM 7:00 AM 7:54 AM 7:55 AM 8:45 AM Low High 4:00 PM 4:00 PM 4:54 PM 4:54 PM TH-55: Theodore Wirth Parkway to TH-100 1:52 2:35 02:20 01:43 02:27 02:11 01:19 2:05 2:57 01:47 02:21 02:17 02: TH-55: TH-100 to Revere Lane 4:43 5:52 05:23 05:16 05:07 06:07 05:00 4:52 19:41 02:47 05:02 04:09 06: TH-55: Revere Lane to I-494 West Ramp 5:18 12:35 04:01 03:55 04:58 04:15 04:41 5:12 5:59 06:40 07:05 07:11 09: TH-55: I-494 West Ramp to Arrowhead Drive 9:03 10:43 09:55 10:01 09:52 09:09 08:19 9:11 10:20 07:31 07:05 08:32 09: TOTAL TH-55: Theodore Wirth Parkway to Arrowhead Drive 20:57 31:45 21:39 20:55 22:24 21:42 19:19 21:21 38:58 18:45 21:33 22:09 28: Alliant

22 Travel Times During Eastbound I-394 Closure WEEK OF 8/03/15 Segment WEEK OF 8/10/15 AM Peak Hour 7:30 AM-8:30 AM Notes: Low Range and High Range based on 15 th and 85 th percentile data Data Sampling Parameters: Average of every 50th vehicle within a one-hour time period Data was unavailable for Segment 1 Westbound, baselines were used to estimate Segment 1 Westbound ranges Estimating Work Zone Performance PM Peak Hour 4:30 PM-5:30 PM Low Range Speed High Range Speed Low Range Speed High Range Speed Baseline Current % Change Baseline Current % Change Baseline Current % Change Baseline Current % Change 1 TH-55: Arrowhead Drive to I-494 West Ramp 31, % % % % 2 TH-55: I-494 West Ramp to Revere Lane 16, % % % % 3 TH-55: Revere Lane to TH , % % % % 4 TH-55: TH-100 to Theodore Wirth Parkway 5, % % % % TOTAL TH-55: Arrowhead Drive to Theodore Wirth Parkway 69, % % % % Segment Eastbound Westbound Distance (ft) Distance (ft) Base FFS (mph) Base FFS (mph) AM Peak Hour 7:30 AM-8:30 AM PM Peak Hour 4:30 PM-5:30 PM Low Range Speed High Range Speed Low Range Speed High Range Speed Baseline Current % Change Baseline Current % Change Baseline Current % Change Baseline Current % Change 4 TH-55: Theodore Wirth Parkway to TH-100 5, % % % % 3 TH-55: TH-100 to Revere Lane 16, % % % % 2 TH-55: Revere Lane to I-494 West Ramp 16, % % % % 1 TH-55: I-494 West Ramp to Arrowhead Drive 31, % % % % TOTAL TH-55: Theodore Wirth Parkway to Arrowhead Drive 69, % % % % Segment AM Peak Hour 7:30 AM-8:30 AM PM Peak Hour 4:30 PM-5:30 PM Low Range Speed High Range Speed Low Range Speed High Range Speed Baseline Current % Change Baseline Current % Change Baseline Current % Change Baseline Current % Change 1 TH-55: Arrowhead Drive to I-494 West Ramp 31, % % % % 2 TH-55: I-494 West Ramp to Revere Lane 16, % % % % 3 TH-55: Revere Lane to TH , % % % % 4 TH-55: TH-100 to Theodore Wirth Parkway 5, % % % % TOTAL TH-55: Arrowhead Drive to Theodore Wirth Parkway 69, % % % % Segment Eastbound Westbound Distance (ft) Distance (ft) Base FFS (mph) Base FFS (mph) AM Peak Hour 7:30 AM-8:30 AM PM Peak Hour 4:30 PM-5:30 PM Low Range Speed High Range Speed Low Range Speed High Range Speed Baseline Current % Change Baseline Current % Change Baseline Current % Change Baseline Current % Change 4 TH-55: Theodore Wirth Parkway to TH-100 5, % % % % 3 TH-55: TH-100 to Revere Lane 16, % % % % 2 TH-55: Revere Lane to I-494 West Ramp 16, % % % % 1 TH-55: I-494 West Ramp to Arrowhead Drive 31, :36 0% :24 0% :48 0% :00 0% TOTAL TH-55: Theodore Wirth Parkway to Arrowhead Drive 69, % % % % 16 Alliant

23 7 Lessons Learned 7.1 Success Stories This project was able to test how construction on a specific corridor would impact traffic conditions on a parallel route. The two larger construction events on I-394 provided a significant change in traffic conditions on TH 55. The data provided by the imeasure system illustrated these impacts, and produced expected changes in traffic volumes and traffic conditions. imeasure is a powerful tool that can document traffic volume levels and provide comparisons over multiple time periods (days, weeks, months, years). The system s travel time estimation algorithm is accurate under most conditions. Manually collected travel time data verified the accuracy of the system as part of this project. Both travel times and arterial level of service (travel speed) are known performance measures that can quantify corridor performance and impacts. In particular, arterial level of service can not only identify an impact, but can also provide an understanding of the level of impact when compared to normal conditions. As part of this project, the group identified construction projects that may affect operations on TH 55. Alliant signed up for notifications, and periodically checked in with the MnDOT Construction Project Manager for updates. This communication allowed the group to know about upcoming construction activities that could result in impacts to traffic conditions. This project used the imeasure data as a reactive system, documenting conditions after the fact. Under these circumstances, having data available within hours was perfectly acceptable. Traffic conditions from the day before could be reviewed first thing the following morning. The Highway 55 corridor proved to be capable of handling changes in traffic volumes within its normal signal operations plan under most conditions. The imeasure system provided validation that the corridor was operating under acceptable parameters. 7.2 Problems Encountered The user interface in imeasure could still use improvement. Data manipulation can be cumbersome for larger corridors. When conducting comparisons between time periods, the availability and consistency of data is extremely important. Communications between traffic signals and the data server must be maintained at all times. If communications is lost, data is not available to calculate travel times or to compare other performance measures. The corridor cannot include intersections controlled as all-way stops (either signed or if signals are on red flash). The algorithms to calculate travel times, intersection delay, and queuing do not work under this scenario. Intersection Delay and Queueing were originally considered as potential performance measures. However, both of these measures do not provide an understanding of the overall corridor performance. While useful to identify spot issues, they do not give an overall evaluation of how the corridor is operating. 17 Alliant