CHAPTER 11 PAVEMENT TYPE DETERMINATION

Transcription

1 CHAPTER 11 PAVEMENT TYPE DETERMINATION 11.1 PAVEMENT TYPE SELECTION FACTORS A highway system designation shall not determine the choice of pavement type. The following factors should be considered when choosing a pavement type: Economics Pavement type determination can be influenced by the results of an Engineering Economic analysis (e.g., a Life-Cycle Cost Analysis) on the cost of construction and future maintenance. Alternate Bidding Pavement type may be determined through Alternate Bidding as described in Section Performance of Similar Pavement in the Area Knowing how a particular design type performed in the past is a valuable guide in predicting future performance. However, there must be a good correlation between conditions and service requirements of the reference pavements and the designs under study. Caution is urged against relying on performance records of reference pavements subjected to much lighter loadings for a large portion of their service life. Caution is also urged when considering the performance of pavements containing materials and/or design features that are no longer commonly used or expected to be used. Reference pavements should be re-analyzed periodically. Adjacent Existing Pavements The choice of pavement type may be influenced by the pavement types of adjacent sections that have similar conditions to the project and that have provided adequate long-term service. Municipal Preference, Participating Local Government Preference While these considerations seem outside the realm of the highway engineer, the highway administrator cannot ignore them. Construction Considerations Various construction considerations may influence the pavement type selection: Seasonal construction constraints Reduction of maintenance and protection of traffic during construction Need for reduced future maintenance in highly congested locations Economic impact on local businesses due to duration of construction project Grades, Curvature and Unusual Loadings Slow-moving vehicles starting and stopping on steep grades and unusual loadings may affect the pavement type selection. The recommended pavement structure, chosen after careful consideration of the above factors, will be designated on Form D Any supporting documentation for the type selection must be included with the copies of Form D-4332 submitted to the Highway Design and Technology Section (HDTS) of the Bureau of Project Delivery. 11-1

2 11.2 LIFE-CYCLE COST ANALYSIS GUIDELINES The policies and methodologies outlined in this Chapter define when a Life-Cycle Cost Analysis (LCCA) must be completed and how to perform the analysis. The HDTS shall review and update (if necessary) the policies and processes every two years, in order to keep up with and reflect the latest innovations, technology developments and costs in the fields of pavement design, construction, maintenance and materials. Stakeholders (including industry) should participate in these reviews. An LCCA must be submitted to the HDTS for all new construction, reconstruction or major structural rehabilitation projects with at least 30,000 square yards of mainline pavement surface work (including pavement and shoulders), regardless of roadway network or funding system. Structural pavement designs are performed for each pavement type alternative and the LCCA is performed to analyze which equivalent structure is most cost-effective over a specified analysis period. It is important that all practical alternatives are considered when performing an LCCA for these projects, from major rehabilitation with either a bituminous or concrete structural overlay to total reconstruction with either pavement type. Justification must be provided when an alternate is not practical and is excluded from the LCCA. The current LCCA Excel spreadsheet can be downloaded from: The total Present Worth costs (Initial Construction + Maintenance Activities + User Delay) of all design alternatives are to be compared and all alternates must have the same analysis period. For treatments that extend life beyond the analysis period, apply a Residual Life Discount to account for the value of the performance beyond the end of the analysis period: Residual Life Discount = Present Worth Cost of Treatment x (Age of End of Analysis Period/Life of Treatment - 1). Note that Present Worth Cost of Treatment is the Present Worth cost of the maintenance activity to which the Residual Life Discount is applied. It does not apply to the Cost for that activity. Perform the LCCA without factoring inflation. A Discount Rate shall be applied to all costs and discounts within the analysis period. The Discount Rate is the five-year rolling average of the annual 30-Year Real Interest Rate on Treasury Notes and Bonds posted by Executive Office of the President, Office of Management and Budget (OMB) Circular A-94. HDTS will provide the updated Discount Rate to all District PMEs each January, based on the information posted at:

3 The cost of all bituminous items, adjusted as per Publication 408 Section , Price Adjustment of Bituminous Materials, will be factored by the provided Asphalt Adjustment Multiplier (AAM). The AAM is to be applied to bituminous costs for both initial construction and future maintenance in the LCCA so as to more accurately estimate the most current unit price of bituminous materials at the time of project bidding. The AAM will be calculated semiannually based on the total of bituminous payments made over the preceding twelve months and bituminous price adjustments applied to those payments. To further clarify, the following equation will be used: AAM = 1 + Adjustments / Total of Bituminous Payments. The AAM will be updated and provided to all District Pavement Management Engineers by the HDTS semiannually during the first week of each July and January. Construction Items The pavement items quantity estimates for each alternative will be based on the actual typical cross section used for the project (e.g. wearing, binder, base, and subbase; or PCCP, treated base, and subbase). The differences in costs for pavement-related items (e.g., pavement relief joints, and approach slabs) must be included in the LCCA when calculating initial costs. Only the differences in these items quantities between alternatives shall be included in the LCCA; do not include the total item quantity for each alternative. The differences in costs for earthwork items must be included in the LCCA when calculating initial costs. To determine the subgrade and excavation quantities, the estimated percentage of the project in total cut, total fill, and cut and fill shall be determined for each alternative. Only the differences in earthwork quantities between alternatives shall be included in the LCCA; do not include the total earthwork quantity for each alternative. Resurfacing When calculating the total cost for resurfacing alternatives, include the cost of pavement resurfacing, shoulder modifications, necessary pavement patching, drainage and guide rail adjustments, maintenance and protection of traffic, etc. For LCCA purposes, the first bituminous overlay for rigid pavements (not including scratch or leveling courses) shall be 4" thick when 9.5 mm Wearing Course mix is used or 4.5" thick when 12.5 mm Wearing Course mix is used. All resurfacing of flexible pavements shall be 1.5" thick when 9.5 mm Wearing Course mix is used or 2" thick when 12.5 mm Wearing Course mix is used. Resurfacing of flexible pavements with new and non-standard overlay materials, such as, Thin Hot Mix Asphalt Overlays or Asphalt Rubber Gap-Graded Wearing Courses shall use the minimum thicknesses issued in any design use guidelines for these type of new or non-standard resurfacing materials. 11-3

4 Shoulders The LCCA must account for shoulder construction and maintenance. The shoulder type must be structurally equivalent for each alternate, i.e., full-depth bituminous shoulders vs. fulldepth concrete shoulders. Miscellaneous Engineering and mobilization costs must not be included in the life-cycle cost analysis. Regarding costs for non-pavement items, such as drainage, guiderail, utility relocations, etc., only the differences between alternatives for these items shall be included in the LCCA. Do not include the total item quantity in each alternative. Type Determination Either of the following will be sufficient to conclusively determine the pavement type: 1. A difference of 10% or more in life-cycle cost, excluding user delay costs. 2. A difference of 20% or more in life-cycle cost, including user delay costs. 3. Engineering judgment, adjacent pavement types, subgrade composition or condition, right-of-way constraints, or other factors may provide justification for pavement type selection, upon HDTS approval. In all other cases, Alternate Pavement Type Bidding (Section 11.6) must be applied to determine pavement type. The impact of constructability/phasing issues and/or maintenance and protection of traffic constraints should be reflected by varying Initial Construction Costs, User Delay Costs, and/or Costs, and not considered separately. If an LCCA is performed more than three (3) years prior to project letting, it must be updated to reflect current prices, traffic data, Discount Rate, Construction Cost Index and any changes to the pavement design. For Alternate Bidding, the LCCA must be performed, or updated, within six months of project letting. Updated LCCA documents must be submitted to HDTS with changes indicated in red font, even if the previous LCCA has been approved by HDTS. Documentation supporting the changes must also be submitted. Upon approval of an LCCA and pavement type selection, pavement type shall not be changed, whether the project is in design or construction status, unless approved by the HDTS GUIDELINES FOR DEVELOPING INITIAL COSTS The following guidelines shall be used to develop initial costs for each particular rehabilitation strategy. Adjust these guidelines to include any items that may occur on a particular project that would affect the initial cost of a particular rehabilitation strategy. 11-4

5 Bituminous Rehabilitation Strategies Bituminous Overlay 1. Design according to Chapter Patching based on actual field measurements. The quantity shall anticipate additional deterioration that will occur between the time of the design field view and the actual construction of the project. Replace concrete pavement with concrete (as per Section 4.2) and bituminous pavement with matching depths of like bituminous courses 3. Slab stabilization where necessary to restore support to the existing concrete pavement. 4. Bituminous tack coat, if necessary. 5. Continuous pavement base drain. Replace as appropriate. 6. Longitudinal and transverse joint cleaning and sealing of concrete pavements. Asphalt joint and crack sealing on bituminous pavements. Use of heavy-duty membranes, as necessary. Sawing and sealing of bituminous overlays on concrete or on existing sawed and sealed bituminous." 7. Type 6 or Type 7 paved shoulders as applicable. 8. Sawing and sealing the overlay over existing transverse and patch joints. 9. Adjusting or replacing existing guide rail and drainage structures as necessary. Bituminous Overlay on Crack and Seated Concrete 1. Cracking and seating the existing concrete pavement. 2. Base repair with Base Course/Superpave Base Course. 3. Continuous pavement base drain. 4. Leveling course (1 inch minimum), includes cross-slope correction. 5. Bituminous overlay (thickness as required by design). 6. Full-depth bituminous shoulders. 7. Resetting and/or replacing guide rail and drainage structures as necessary. Bituminous Overlay on Rubblization 1. Rubblizing and seating the existing concrete pavement. 11-5

6 2. Base repair with AASHTO #1 aggregate, as necessary. 3. Continuous pavement base drain. 4. Leveling course (1 inch minimum), includes cross-slope correction. 5. Bituminous thickness, as required by design. 6. Full-depth bituminous shoulders. 7. Resetting and/or replacing guide rail and drainage structures as necessary. Bituminous Reconstruction Remove and Replace 1. Design according to Chapter Undercutting and replacement of subgrade, if necessary. 3. Continuous pavement base drain Concrete Rehabilitation Strategies Concrete Pavement Rehabilitation 1. Patching and spall repair based on actual field measurements and/or deflection tests. The quantity shall anticipate additional deterioration that will occur between the time of the design field view and the actual construction of the project. 2. Slab stabilization around patches and where necessary to restore full support to the pavement. 3. Slabjacking as required. 4. Diamond grinding 50% of project to improve ride quality, or to improve friction if necessary with the exception of concrete pavements constructed with Vanport Limestone aggregate. (Data has shown that grinding a concrete surface removes the effective mortar layer on the pavement and the skid resistance of the exposed Vanport Limestone is susceptible to rapid decline.) 5. Continuous pavement base drain. 6. Rehabilitation of all failed transverse joints, if not previously performed. Otherwise, cleaning and resealing of all joints that have the proper shape factor. 7. Cleaning and sealing all longitudinal joints and pavement/shoulder joints. 8. Adjusting or replacing guide rail and drainage structures as necessary. 11-6

7 Concrete Overlays Bonded and Unbonded 1. Design in accordance with Chapter Rehabilitation of all failed transverse joints. 3. Concrete pavement patching based on actual field measurements. 4. Slab stabilization around patches and where necessary to restore uniform support. 5. Cleaning and sealing all existing joints, if unbonded overlay. 6. Continuous pavement base drain. 7. Concrete shoulders. 8. Leveling course and bond breaker to be included, if unbonded design. 9. Adjusting or replacing all guide rail and drainage structures as necessary. 10. Fill widening to retain proper shoulder widths, and checking bridge underclearances. Concrete Overlay - Unbonded Crack and Seat 1. Cracking and seating existing concrete pavement. 2. Base repair with HMA Base Course/Superpave Base Course as necessary. 3. Continuous pavement base drain. 4. Leveling course and bond breaker includes cross-slope correction. 5. Unbonded concrete overlay, as designed using the procedure in Chapter Concrete shoulders. 7. Resetting and/or replacing guide rail and drainage structures as necessary. 8. Fill widening to retain proper shoulder widths, and checking bridge underclearances. Concrete Reconstruction on Rubblization 1. Rubblizing and seating existing concrete pavement. 2. Base repair with AASHTO #1 aggregate as necessary. 3. Continuous pavement base drain. 11-7

8 4. Leveling course and bond breaker includes cross-slope correction. 5. Concrete thickness, as required by design. 6. Concrete shoulders. 7. Resetting and/or replacing guide rail and drainage structures as necessary. 8. Fill widening to retain proper shoulder widths, and checking bridge underclearances. Concrete Reconstruction Remove and Replace 1. Design according to Chapter Undercutting and replacement of subgrade, if necessary. 3. Continuous pavement base drain MAINTENANCE STRATEGIES FOR LIFE-CYCLE COST ANALYSIS (LCCA) Bituminous New Construction or Reconstruction (including construction on rubblized concrete) 50 Year Pavement Life 5 years Clean and Seal, 25% of longitudinal joints Crack Seal, 500 lineal feet per mile Seal Coat or Micro Surface shoulders, if Type 1, 1S, 3, 4, 6 or 6S 10 years Full Depth Patching, 2% of pavement area Mill wearing course Bituminous Inlay, 1.5" or 2.0" Seal Coat or Micro Surface shoulders, if Type 1, 1S, 3, 4, 6 or 6S 15 years Clean and Seal, 25% of longitudinal joints Crack Seal, 500 lineal feet per mile Seal Coat or Micro Surface shoulders if Type 1, 1S, 3, 4, 6 or 6S 11-8

9 20 years Full Depth Patching, 2% of pavement area Leveling Course, 60 PSY Bituminous Overlay, 1.5" or 2.0" Type 7 Paved Shoulders Adjust guide rail and drainage structures, if necessary 25 years Clean and Seal, 25% of longitudinal joints Crack Seal, 500 lineal feet per mile 30 years Full Depth Patching, 2% of pavement area Mill Wearing Course Bituminous Inlay, 1.5" or 2.0" Seal Coat or Micro Surface shoulders 35 years Clean and Seal, 25% of longitudinal joints Crack Seal, 500 lineal feet per mile 40 years Full Depth Patching, 2% of pavement area Leveling Course, 60 PSY Bituminous Overlay, 1.5" or 2.0" Type 7 Paved Shoulders Adjust guide rail and drainage structures, if necessary 45 years Clean and Seal, 25% of longitudinal joints Crack Seal, 500 lineal feet per mile Seal Coat or Micro Surface shoulders 11-9

10 Concrete New Construction, Reconstruction (including construction on rubblized concrete), Unbonded Overlay 50 Year Pavement Life (applying Residual Life Discount) 8 years Clean and Seal, 25% of longitudinal joints including shoulders Clean and Seal, 25% of transverse joints 15 years Concrete Patching, 2% of pavement area Diamond Grinding, 50% of pavement area Clean and Seal, all longitudinal joints including shoulders Clean and Seal, all transverse joints 25 years Concrete Patching, 8% of pavement area Clean and Seal, all longitudinal joints including shoulders Clean and Seal, all transverse joints Leveling Course, 60 PSY Bituminous Overlay, 4" or 4.5" Saw and Seal, all transverse joints Type 7 Paved Shoulders Adjust guide rail and drainage structures, if necessary 30 years Clean and Seal, 25% of longitudinal and transverse joints Crack Seal, 500 lineal feet per mile Seal Coat or Micro Surface shoulders 35 years Mill Wearing Course Bituminous Inlay, 1.5" or 2.0" Saw & Seal, all transverse joints Seal Coat or Micro Surface shoulders 40 years Clean & Seal, 25% of longitudinal and transverse joints Crack Seal, 500 lineal feet per mile Seal Coat or Micro Surface shoulders 11-10

11 45 years Concrete Patching, 5% of pavement area Leveling Course, 60 PSY Bituminous Overlay, 1.5" or 2.0" Saw & Seal, all transverse joints Type 7 Paved Shoulders Adjust guide rail and drainage structures, if necessary Note: In Year 50, five years of life remain on the last overlay. Therefore a Residual Life Discount is applied when comparing to New Bituminous Construction or Reconstruction in order to equate total pavement lives Bonded Concrete Overlay 30 Year Pavement Life 5 years Clean and Seal, 25% of longitudinal joints including shoulders Clean and Seal, 25% of transverse joints Seal Coat or Micro Surface shoulders, if bituminous 10 years Concrete Patching, 5% of pavement area Diamond Grinding, 50% of pavement area Clean and Seal, 25% of longitudinal joints including shoulders Clean & Seal, 25% of transverse joints Seal Coat or Micro Surface shoulders, if bituminous 15 years Clean and Seal, 25% of longitudinal joints including shoulders Clean and Seal, 25% of transverse joints Seal Coat or Micro Surface shoulders, if bituminous 20 years Concrete Patching, 8% of pavement area Clean and Seal, all longitudinal joints including shoulders Clean and Seal, all transverse joints Leveling Course, 60 PSY Bituminous Overlay, 4" or 4.5" Saw and Seal, all transverse joints Type 7 Paved Shoulders Adjust guide rail and drainage structures, if necessary 11-11

12 25 years Clean and Seal, 25% of sawed and sealed joints Crack Seal, 500 lineal feet per mile Seal Coat or Micro Surface shoulders Concrete Pavement Rehabilitation (CPR) & Bituminous Overlay 30 Year Pavement Life 10 years Mill Wearing Course Bituminous Inlay, 1.5" or 2.0" Saw & Seal, all transverse joints Seal Coat or Micro Surface shoulders, if Type 1, 1S, 3, 4, 6 or 6S 15 years Clean & Seal, 25% of sawed & sealed joints Crack Seal, 500 lineal feet per mile Seal Coat or Micro Surface shoulders, if Type 1, 1S, 3, 4, 6 or 6S 20 years Concrete Patching, 2% of pavement area Leveling Course, 60 PSY Bituminous Overlay, 1.5" or 2.0" Saw & Seal, all transverse joints Type 7 Paved Shoulders Adjust guide rail and drainage structures, if necessary 25 years Clean & Seal, 25% of longitudinal and transverse joints Crack Seal, 500 lineal feet per mile Seal Coat or Micro Surface shoulders Bituminous Overlay on Bituminous Pavement 10 Year Pavement Life 5 years Clean and Seal, 25% of longitudinal joints Crack Seal, 500 lineal feet per mile Seal Coat or Micro Surface shoulders, if Type 1, 1S, 3, 4, 6 or 6S 11-12

13 Ultra-Thin Whitetopping on Bituminous Pavements 10 Year Pavement Life 5 years Clean and Seal, 25% of longitudinal joints including shoulders Clean and Seal, 25% of transverse joints Seal Coat or Micro Surface shoulders 11.5 USER DELAY COSTS Roadway users incur Costs while roads are being maintained, repaired or reconstructed. Costs must be accounted for in the life-cycle cost analysis for each alternate to be compared. These costs must be determined, and included in the LCCA, for each year of each alternate that user delays are incurred, including the year of Initial Construction if the Costs vary for the alternates due to differences in traffic control and/or project phasing. Costs are divided into three categories: 1. Idling Cost (or Speed Reduction Cost) 2. Time Value Costs (for Idling and Stopping) 3. Stopping Cost If any of these types of user delays are incurred, the number of vehicles affected by the delay must be calculated. The following sections provide an overview of the items that User Delay Costs entail Delayed Vehicles In order to calculate the number of delayed vehicles during an activity in a specific year, the following traffic information is required: 1. Initial ADT, Design Year, and Design Year ADT 2. Composition of the traffic mix by vehicle class (i.e., cars, single unit trucks, combination trucks) 3. Directional Factor 4. Total Days of the Activity From this information, the following items must then be calculated: Traffic Growth Factor ADT in each Activity Year ADT in each Direction 11-13

14 ADT Delayed in each Direction Total Number of Vehicles Delayed During the Activity Total Number of Vehicles Delayed in each vehicle class Stopped Vehicles If during construction, the number of lanes that are being maintained is reduced, then the capacity of the facility is affected. If the actual traffic exceeds capacity, then a backup will occur as traffic enters the construction zone. Vehicles will be stopped due to congestion at the restricted area, and Stopping Costs must be determined. To determine the number of vehicle stops, the ADT for the applicable year and the composition of the traffic must be determined, as described for determining Delayed Vehicles. In addition, the following items must be calculated: 1. Hourly breakdown of traffic 2. Roadway Capacity The hourly breakdown (by percent of the total daily traffic) can be determined by a traffic study. If a study is not done, Table 11.1 provides hourly percentages of total vehicles based on average values for all roadways in a specific Traffic Pattern Group category. Roadway Capacity is determined for one direction, and is dependent on the total number of lanes in that direction under normal operation, and the number of lanes maintained during construction. Figure 6-12 of the Highway Capacity Manual, Special Report 209, by the Transportation Research Board can be used to determine roadway capacity at a desired confidence level. For the purposes of determining the number of stopped vehicles while calculating Costs, this figure has been simplified as shown in Table

15 Table 11.1 Hourly Percentages of Total Vehicles * HOUR TRAFFIC PATTERN GROUP TRAFFIC PATTERN GROUP (TPG) CATEGORIES: 1: Urban Interstate 6: North Rural Minor Arterials 2: Rural Interstate 7: Central Rural Minor Arterials 3: Urban Principal Arterial 8: North Rural Collectors 4: Rural Principal Arterial 9: Central Rural Collectors 5: Urban Minor Arterials or Collectors 10: Special Recreational * From PennDOT, Bureau of Planning and Research, Transportation Planning Division, Pub. 601 "2007 Pennsylvania Traffic Data"Factoring Process: Traffic Adjustment Factors, Table

16 Table 11.2 Roadway Capacity * Number of Lanes (1 direction) Normal Operation During Construction Capacity (veh/hr/lane) * From Figure 6-12 of the Highway Capacity Manual, Special Report 209, by the Transportation Research Board, based on ninety percent confidence level Example Calculations EXAMPLE 1 Urban Interstate Initial ADT (Year 2010) = 30,500 Design Year ADT (Year 2030) = 49,978 Directional Distribution Factor = 0.50 Traffic Breakdown (by percentage): Traffic Breakdown (by vehicle type): 88% Cars 12% Trucks - 20% Single Unit - 80 % Combination HOUR % VEHICLES HOUR % VEHICLES HOUR % VEHICLES Under normal conditions, the roadway has two lanes in each direction. Calculate the number of delayed and stopped vehicles in each class during the maintenance activities in Year 15 (2025) if one lane will be maintained in one direction as follows: 1) Traffic Growth Factor = (49,978 / 30,500) [1/20] = ) Percent of Daily Vehicles Delayed = 100 (Lanes will remain closed all day, and traffic in both directions is affected) 3) ADT in Year 2025 = 30,500 x 1.0 x (1.025) [15] = 44,

17 4) ADT in One Direction = 44,173 x 0.50 = 22,087 (Since the Directional Distribution Factor equals 0.50, the ADT is the same in both directions.) 5) ADT in One Direction for each Hour: HOUR VEHICLES HOUR VEHICLES HOUR VEHICLES , , , , , , , , , , , , , ) Roadway Capacity in One Direction = 1260 veh/hr (From Table 11.2, one lane open in each direction) (Note that the hour from 7:00 am to 8:00 am is the first hour of the day that capacity is exceeded.) 7) Number of Vehicle Stops in One Direction: Number of Hourly Vehicle Stops in One Direction = (Hourly % of Vehicles) x (ADT in One Direction) - (Roadway Capacity in One Direction) + (Previous Hour's Queue) Since the Directional Distribution Factor and the lane configuration is the same in both directions, the Roadway Capacity and the Number of Hourly Vehicle Stops in both directions is the same. HOUR VEHICLES HOUR VEHICLES HOUR VEHICLES , , Total = 4,812 vehicles/day 8) Total Number of Stopped Vehicles = 4,812 x 2 = 9,624 vehicles/day (Conditions are the same in both directions) 9) Total Number of Vehicles Delayed During Activity = 22,087 x 2 = 44,174 vehicles/day in both directions 11-17

18 EXAMPLE 2 10) Total Number of Vehicle Stops During Activity = 4,812 x 2 = 9,624 vehicles/day in both directions 11) Vehicles Delayed by Class: Cars: 44,174 x 0.88 = 38,873 S.U. Trucks: 44,174 x 0.12 x 0.20 = 1,060 Comb. Trucks: 44,174 x 0.12 x 0.80 = 4,241 12) Vehicle Stops by Class: Cars: 9,624 x 0.88 = 8,469 S.U. Trucks: 9,624 x 0.12 x 0.20 = 231 Comb. Trucks: 9,624 x 0.12 x 0.80 = 924 All of the same conditions as Example 1, except one lane in each direction will be closed only during the hours of 8:00 am to 4:00 pm (8 hours): 1) Percent of Daily Vehicles Delayed = 45.7 (Sum of the Hourly Percentages of Total Traffic for the hours of lane closure.) 2) ADT Delayed in One Direction = 22,087 x = 10,094 (Since the Distribution Factor equals 0.50, the ADT is the same in both directions.) 3) Number of Hourly Vehicle Stops in One Direction: HOUR VEHICLES HOUR VEHICLES HOUR VEHICLES Total = 461 vehicles 8) Total Number of Stopped Vehicles = 461 x 2 = 922vehicles (Conditions are the same in both directions) 9) Total Number of Vehicles Delayed During Activity = 10,094 x 2 = 20,188 vehicles/day in both directions 10) Total Number of Vehicle Stops During Activity = 461 x 2 = 922 vehicles/day in both directions 11-18

19 11) Vehicles Delayed by Class: Cars: 20,188 x 0.88 = 17,765 S.U. Trucks: 20,188 x 0.12 x 0.20 = 485 Comb. Trucks: 20,188 x 0.12 x 0.80 = 1,938 12) Vehicle Stops by Class: Added Time Cars: 922 x 0.88 = 811 S.U. Trucks: 922 x 0.12 x 0.20 = 22 Comb. Trucks: 922 x 0.12 x 0.80 = 89 Due to the reduced speeds, travel time is increased for all vehicles that pass through a construction zone. This added time must be determined in order to calculate Costs. The added time may be dependent on the traffic control pattern to be implemented (i.e., highspeed crossovers, detours, etc.). For each traffic control pattern to be implemented during the life-cycle, the following information must be known: 1. Restricted Flow Length 2. Initial and Reduced Speeds The following items must then be calculated: 1. Restricted Flow Time 2. Overall Increased Travel Time The Restricted Flow Length is the length of roadway for which a speed reduction or lane closure is implemented. If traffic is detoured, the detour length is the Restricted Flow Length. The Restricted Flow Time is the time required to travel through the Restricted Flow Length. If traffic is detoured, then the Restricted Flow Time equals the time necessary to travel through the Detour Length. Restricted Flow Time is used to determine Idling Costs. The Overall Increased Travel Time is the difference between the Restricted Flow Time and the time required to travel the same distance at the normal posted speed limit. Overall Increased Travel Time is necessary to compute the Time Value Cost for Idling. For each traffic control pattern that applies a different Restricted Flow Length, Initial Speed, or Reduced Speed, there is a different Restricted Flow Time and the Overall Increased Travel Time

20 Cost Factors Cost factors for Stopping, Idling, and Time Value were determined for cars, single-unit trucks, and combination trucks in 1972 and were published in NCHRP Report 133, Procedures for Estimating Highway User Costs, Air Pollution, and Noise Effects. (Table 11.3 presents the information from Table 5 of NCHRP Report 133.) The Time Value Costs were $3.00/hr for cars and $5.00/hr for all trucks Inflation Factor The cost factors shown in Table 11.3 are inflated to present day costs by use of the Inflation Factor, which is based on the Engineering News-Record (ENR) Construction Cost Index. The 1972 Construction Cost Index is The current Construction Cost Index is found in the current edition of ENR under "Market Trends." The Inflation Factor (I) is determined as follows: I = Current Index 1972 Index Table 11.3 Added Time and Vehicle Running Costs Per 1000 Stops, and Idling Costs (Shading indicates interpolated values) Initial Added Time (hr/1000 stops) (excludes Idling Time) Added Cost ($/1000 stops) a (excludes Idling Cost) Speed (mi/hr) Passenger Car Single Unit Truck Combination Truck Passenger Car Single Unit Truck Combination Truck Idling Cost ($/veh-hr) b a Includes fuel, tires, engine oil, maintenance, and depreciation. b Includes fuel, engine oil, maintenance, and depreciation. Source: R. Winfrey, Economic Analysis for Highways (International Textbook Co., 1969) 923 pp

21 Example Calculations (continued) Calculate the Costs based on the total number of delayed and stopped vehicles that were calculated in Section , Example 1: Delayed: Stopped: Cars: 38,873 Cars: 9,624 S.U. Trucks: 1,060 S.U. Trucks: 231 Comb. Trucks: 4,241 Comb. Trucks: 924 The following information is also known: Restricted Flow Length = 4.7 miles Initial Speed = 55 mph Reduced Speed = 40 mph Current Construction Cost Index = 8,574 1) Restricted Flow Time = Restricted Flow Length/Reduced Speed = 4.7/40 = hr 2) Overall Increased Travel Time = (Restricted Flow Length / Reduced Speed) - (Restricted Flow Length / Initial Speed) = (4.7/40) - (4.7/55) = hr 3) Inflation Factor = Current Index / 1972 Index = 8,574/1753 = ) Cost Factors (From Table 11.3): Added Time Added Cost Idling Time Time Value (hr/1000 stops) ($/1000 stops) ($/veh-hr) ($/hr) Cars S.U. Trucks Comb. Trucks ) Current Cost Factors: Added Time Added Cost Idling Time Time Value (hr/1000 stops) ($/1000 stops) ($/veh-hr) ($/hr) Cars S.U. Trucks Comb. Trucks

22 6) Costs: CARS Number of Added Delay Cost Vehicles Time per Unit COST Idling 38,873 x x = 2,782 Time Value/Idling 38,873 x x = 12,502 Stopping 9,624 x x = 706 Time Value/Stopping 9,624 x 5.84/1000 x = 565 S.U. TRUCKS Idling 1,060 x x = 84 Time Value/Idling 1,060 x x = 568 Stopping 231 x x = 33 Time Value/Stopping 231 x 8.07/1000 x = 31 COMBINATION TRUCKS Idling 4,241 x x = 361 Time Value/Idling 4,241 x x = 2,272 Stopping 924 x x = 586 Time Value/Stopping 924 x 20.72/1000 x = Days of Construction TOTAL $ 20,810 The total daily Cost is multiplied by the total number of Days of Construction that the roadway will be under repair. The total number of Days of Construction is determined by applying daily production rates to the specific work activities to be performed, accounting for concurrent activities, and summing the days of controlling operations. Production rates will vary depending on whether the is a short-term (partial-day) or long-term (full-day) closure. Standard values to be used in LCCAs are provided in Table 11.4; these values are based on typical production rates provided by industry. Concurrent activities are indicated and accounted for in the LCCA Excel spreadsheet, so that the total days for each maintenance year reflect the total required time of closure and not the sum of each activity s duration in that year

23 Activity Table 11.4 Standard Production Rates for Maintenance Activities Production Rate Per Shift Short Term Long Term Closure Closure Adjust Drainage Structures 8 inlets 10 inlets Bituminous Inlay or Overlay 1,800 tons 2,400 tons Clean & Seal Transverse Joints concrete surface 3,200 LF 4,200 LF Clean & Seal Joints bituminous surface 6,000 LF 8,000 LF Clean & Seal Longitudinal Joints concrete surface 6,500 LF 8,500 LF Concrete Patching 300 SY 400 SY Crack Seal 6,000 LF 8,000 LF Diamond Grinding 1,500 SY 2,000 SY Full-Depth (Bituminous) Patching 75 CY 150 CY Leveling Course, 60 PSY 1,800 tons 2,400 tons Mill Wearing Course 16,400 SY 21,900 SY Reinstall Guide Rail 1,500 LF 2,000 LF Remove Existing Guide Rail 2,250 LF 3,000 LF Saw & Seal Transverse Joints 6,400 LF 8,500 LF Seal Coat or Micro Surface Shoulders 16,000 SY 18,000 SY Type 7 Paved Shoulders 1,800 tons 2,400 tons 11.6 ALTERNATE BIDDING The following guidelines on Alternate Bidding have been developed to facilitate competition in the paving industry, and to allow PennDOT to realize bid savings for construction projects and take advantage of fluctuating material costs without compromising sound engineering principles and practices. It is in the best interest of PennDOT to apply Alternate Bidding whenever appropriate so that both industries are competitive and lower costs can be realized. Rather than a predetermined pavement type selection based on an LCCA and historical cost information, there is motivation to determine pavement type based on low bid. Both industries will be made aware of the upcoming Alternate Bidding project through a formal quarterly direct mailing by the HDTS. Alternate Bidding requires the determination of a C-Factor which accounts for future maintenance costs, but excludes Costs, and is added to the construction cost so that the low bid is based on life-cycle costs. Additional requirements for Alternate Bidding are as follows: Alternates must be equivalent, meaning they provide comparable levels of service and performance over the same analysis period. The bid package will indicate the appropriate C-Factors for each alternative, determined by PennDOT based on LCCA methodology for the project

24 Typical sections for all alternatives must meet RC standards, DM-2 and Pub. 242 requirements. Lane width, shoulder width, cross slope and all other geometric features unrelated to pavement type, shown on the Typical Sections must remain as per the plans Alternate Bidding Project Selection Alternate Bidding shall be considered for any new construction, reconstruction or major structural rehabilitation project. Alternate bidding stimulates competition in the paving market, resulting in the potential for considerable savings in construction costs. Enhanced competition in the paving market also spurs innovation and improved pavement quality. Alternate bidding also takes advantage of fluctuating material costs that cannot be predicted during the preconstruction phase of a project. When an LCCA is not required for a project, as per Section 11.2, pavement type selection is based on initial costs or other factors. Alternate Bidding may still be considered in these cases, with no C-Factor calculation, using alternate designs that have the same scope of treatment, service lives and expected performance, and with approval by the HDTS. When a new construction, reconstruction or major rehabilitation project requires an LCCA, Alternate Bidding must be applied, except as defined in Section 11.2, Type Determination, or with approval by the HDTS. The HDTS is responsible for monitoring and tracking Alternate Bidding projects and results. For Alternate Bidding projects, pavement type shall not be changed after the project is awarded to a contractor unless approved by the HDTS. The pavement type selection was the basis of the contract award and post-award change orders for pavement type negate the purpose of the alternate bidding process. Alternate Bidding projects may be advertised in one of three ways: 1. Plans, cross-sections, typical sections, quantities, and traffic control plans are not developed prior to bid for any alternate. 2. Plans, cross-sections, typical sections, quantities, and traffic control plans are developed for one pavement alternate prior to bid. Typical sections are provided for all alternates. 3. Plans, cross-sections, typical sections, quantities, and traffic control plans are developed for all pavement alternates prior to bid. For options 1 and 2, any alternate that is not designed prior to bid must be accompanied with Design-Build provisions. For options 2 or 3, bidders may also propose an alternate design with the same pavement type as the as designed pavement structure; all applicable revisions to plans, cross-sections, typical sections, quantities, traffic control plans must be developed by the bidder

25 Options 1 and 3 are preferred methods for advertising Alternate Bidding projects because they allow all bidders to develop bids from comparable amounts of information and provide no bidders with an inherent advantage in preparing cost estimates and bid documents. Option 2 should only be considered for projects in the Final Design phase prior to April 1, 2013 and development of a full set of complimentary plans will result in a significant delay in advertising a project. Although option 3 may increase the burden on the Department during the preconstruction phase (design and management), the benefits of competition potentially outweigh the burden C-Factor Calculation The C-Factor is determined by summing the Present Worth (PW) value of the future Maintenance and the Residual Life Discount determined by the LCCA: C = (PW maint + Residual Life Discount) Where: C = C-Factor PW maint = PW of future maintenance costs, excluding Costs Residual Life Discount = Treatment Present Worth Cost x (Age of End of Analysis Period/Life of Treatment - 1)