National Academies Press: OpenBook

Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future (2019)

Chapter: Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools

« Previous: Appendix G: Potential Impacts of Climate Change on the Interstate Highway System
Page 457
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 457
Page 458
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 458
Page 459
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 459
Page 460
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 460
Page 461
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 461
Page 462
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 462
Page 463
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 463
Page 464
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 464
Page 465
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 465
Page 466
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 466
Page 467
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 467
Page 468
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 468
Page 469
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 469
Page 470
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 470
Page 471
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 471
Page 472
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 472
Page 473
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 473
Page 474
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 474
Page 475
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 475
Page 476
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 476
Page 477
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 477
Page 478
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 478
Page 479
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 479
Page 480
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 480
Page 481
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 481
Page 482
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 482
Page 483
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 483
Page 484
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 484
Page 485
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 485
Page 486
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 486
Page 487
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 487
Page 488
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 488
Page 489
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 489
Page 490
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 490
Page 491
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 491
Page 492
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 492
Page 493
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 493
Page 494
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 494
Page 495
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 495
Page 496
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 496
Page 497
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 497
Page 498
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 498
Page 499
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 499
Page 500
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 500
Page 501
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 501
Page 502
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 502
Page 503
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 503
Page 504
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 504
Page 505
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 505
Page 506
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 506
Page 507
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 507
Page 508
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 508
Page 509
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 509
Page 510
Suggested Citation:"Appendix H: Summary of HERS, NBIAS, and PHT Modeling Tools." National Academies of Sciences, Engineering, and Medicine. 2019. Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future. Washington, DC: The National Academies Press. doi: 10.17226/25334.
×
Page 510

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Appendix H Summary of HERS, NBIAS, and PHT Modeling Tools The two models used by the Federal Highway Administration (FHWA) to address future investment and performance issues are the Highway Eco- nomic Requirements System (HERS) and the National Bridge Investment Analysis System (NBIAS). The HERS1 and NBIAS2 models are used to forecast the future conditions and performance of highways in the Condi- tions and Performance Report, known as the C&P Report, which the U.S. Department of Transportation (U.S. DOT) submits to Congress every 2 years. The C&P Report fulfills the mandate for a report on future highway investment requirements that the Congress first established in 1965. The HERS modeling tool analyses highway sections that are not related to bridges and structures while NBIAS specifically models bridges and struc- tures. The information about HERS as well as the related graphics and tables provided in this appendix are drawn from FHWA technical reports and related articles (Coley and Lwin 2014; U.S. DOT 2005). The informa- tion related to NBIAS is derived from C&P materials and publications by experts (Coley n.d.; FHWA and FTA 2016; Robert and Gurenich 2008; Robert and Sissel n.d.). A third tool, the Pavement Health Track (PHT) analysis tool, also devel oped under the sponsorship of FHWA, is an engineering software tool for determining and reporting the health of pavement networks in terms of 1 This appendix describes HERS 2015. FHWA is working on new enhancements to the HERS, which are not described here. 2 This appendix describes NBIAS version 4.0. FHWA is working on new enhancements to the NBIAS, which are not described here. 457

458 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM pavements remaining service life (RSL). In this appendix, the information about PHT is based on material from the PHT User’s Guide (FHWA 2013b) and Technical Information report (FHWA 2013a).3 In particular, PHT allows users to determine pavement health in terms of pavement life, ride-ability, or distress by pavement types under vari- ous environmental and administrative conditions, such as climate, func- tional classification, or rural/urban environment, on projects, corridors, and networks. HIGHWAY ECONOMIC REQUIRMENTS SYSTEM (HERS) HERS estimates national investment needs relative to user-specified targets. It, however, does not analyze how much funding should be raised at dif- ferent levels of government. HERS has many practical applications for a transportation agency, including long-range planning, programming, per- formance measures management, needs assessments, and legislative decision support. At its most basic, HERS addresses the questions: “if we invest in highways at a certain level, what are the performance implications?” and vice versa, “if we are looking for a specific level of performance, what level of investment is needed?” It does so by predicting future conditions and implementing a variety of alternative improvements to address deficiencies. In both cases, deficiencies are first defined, then improvements are devel- oped to address the deficiencies. In the course of selecting improvements, the expected impacts of those on the system are evaluated. Through this process, HERS estimates three kinds of benefits that possible highway im- provements have if implemented: benefits to highway users in the form of travel time, operating vehicle costs, and safety; benefits to highway agencies in the form of reduced maintenance costs; and finally the benefit of reduced vehicle emissions. In HERS, the selection of recommended improvements is based on benefit-cost analysis of alternatives. Table H-1 summarizes the investment categories that HERS evaluates. Capital improvements that are not modeled in HERS include safety im- provements such as rumble strips, safety edges, median treatments, signal- ized intersection improvements, and guardrails. Landscape improvements are also not included in the modeling. The underlying data for the HERS model are gathered from the High- way Performance Monitoring System (HPMS). HPMS is a national-level highway information system that includes data on the extent, condition, performance, use, and operating characteristics of the nation’s highways. The HPMS database covers highways eligible for federal aid, that is, all 3 While this section of the appendix provides only a brief summary of PHT, more detailed information can be found at https://www.fhwa.dot.gov/pavement/healthtrack.

APPENDIX H 459 roads except local roads and rural minor collectors. Within the database, the highway network is divided into sections homogeneous over their length. The sections sampled for the HPMS represent short sections vary- ing in length between 1 and 20 miles approximately and are geographi- cally scattered. The sample size, however, is designed to achieve target level of statistical precision for the purpose of estimating vehicle-miles traveled (VMT) by state and highway type. Overall, the database includes detailed data of more than 100,000 randomly sampled sections. The data are collected annually by state departments of transportation (DOTs) and submitted to FHWA. For conducting technical analyses, HPMS comprises two basic parts: 1. Universe data—a relatively limited number of data items for all mileage classified as Interstates, freeways, arterials, and collectors. 2. Sample Panel data—a large set of data items for a sample of highway mileage classified as Interstates, freeways, arterials, and collectors. Many states “oversample” and provide nearly complete coverage for the Interstate System. Nationally, about 50 percent of all Interstate mileage is covered by the Sample Panel. HERS uses this Sample Panel data. Table H-2 reviews the HMPS inputs into HERS. HERS is not a network model. It does not forecast demand for travel between origins and des- tinations, and it does not assign that demand to paths through the net- work, such as is done with the travel demand forecasting models used by TABLE H-1 HERS Investment Categories and Improvements Categories Improvements Evaluated Pavement Preservation* Resurfacing Reconstruction (pavement surface layers only) Increasing Interstate Capacity to Carry Traffic Additional travel lanes Wider lanes Operations and Intelligent Transportation Systems Ramp metering Incident management Variable speed limits Integrated corridor management Weather management *Most pavement preservation, capacity expansion, and operational improvements projects also improve safety.

460 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM TABLE H-2 HPMS Inputs into HERS TRAFFIC Inputs Average Annual Daily Traffic (AADT) Base year level Forecast for future year (usually current year plus 20) Vehicle composition— Light-Duty Vehicles (small autos, medium autos, 4-tire trucks) Single Unit Trucks (6-tire trucks and 3–4 axle trucks, including buses) Combination Truck (4-axle combination and 5-axle combination) Directional and “K” Factors Traffic Control Devices Signals—number and type Stop signs—number GEOMETRY Inputs Widths Lanes, median, shoulders Types Median and shoulders Grades Horizontal and vertical Improvement history Widening feasibility PAVEMENTS Inputs Surface and base Types and thickness Pavement roughness and present serviceability rating New distress measures Rutting Faulting Fatigue cracking Transverse cracking OTHER Inputs Number of through lanes Peak versus counter peak Turn lanes Located on National Highway System? Speed limit

APPENDIX H 461 metropolitan planning organizations (MPOs) and state DOTs. Rather, each HPMS section is considered in isolation. Traffic growth rates developed by the states when they submit HPMS are used to forecast future traffic on each segment. HERS conducts its analysis through a set of time frames that are equal in length; these are called funding periods and involve 5-year increments. For example, if estimates are needed for a 20-year overall analysis period, as in the case for the C&P reports, the HERS analysis is split into four 5-year funding periods to evaluate the investment needs and level of per- formance of the evaluated road infrastructure. HERS evaluates each HPMS section individually. In doing so, it screens for deficiencies by engineering technical standards and identifies potential remedial improvements. HERS operates in what could be called a funding- constrained mode, meaning that it recommends the most cost-beneficial of the improvement candidates. The first step is to compare conditions on the section to a set of deficiency values to screen for sections that are candi- dates for improvement. If a section is deficient, HERS begins its benefit-cost analysis. In general terms the analysis process consists of the following: • A set of improvements are defined to address deficiencies on the highway section. Multiple deficiencies are allowed. Deficiencies are related to geometric conditions (cross-section and alignment), congestion, and pavement condition. • For each potential improvement, the impacts of the improvement on performance are estimated; these impacts are the benefits. Costs for the improvement are derived from unit cost information and the size of the improvement. HERS then selects the improvement with the best benefit-cost ratio (BCR). • HERS keeps track of improvement costs in a given pass through the data. In that given pass, it also records the new enhanced perfor- mance for the sections with the new implemented improvements. • In the next pass through the data (in the 5-year funding period), performance for the section is updated to account for traffic growth and pavement deterioration. The whole process is then repeated to evaluate any improvements that might be warranted in the new funding period. In addition to the main HERS engine that conducts the benefit-cost analysis, HERS includes a number of preprocessors and submodels that enhance the capabilities of the primary engine. The preprocessors perform their analysis outside of HERS and ultimately provide their results as an input file for HERS. On the other hand, the submodels are internal to HERS and their function is to perform specialized functions to enhance the overall

462 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM analysis. Preprocessing calculations include, for instance, validation checks and corrections to HPMS input data. For example, data items for truck traffic are frequently missing within the HPMS database; this particular pre- processor fills this gap by providing 20-year projections for these measures. HERS also includes an Operational Improvements preprocessor that assigns operational improvement strategies to HPMS sections based on congestion level. The Operational Improvements preprocessor does the impact analysis without subjecting its selected improvements to benefit-cost analysis. In fact, the preprocessor is a separate model that produces an input file for HERS that includes adjustment factors that account for increased capacity, reduced delay, reduced incident duration, and improved safety. Therefore, with the Operations Improvements preprocessor engaged, HERS uses an HPMS dataset that already has operations strategies deployed. Any ad- ditional improvements that HERS assigns is done assuming that these operational strategies are in place and have improved capacity and safety or both to some degree. Through its analysis, HERS monetizes benefits from reductions in travel time, vehicle operating costs, crashes, emissions, and highway maintenance costs. To analyze these and in addition to the main HERS engine, HERS also uses a variety of submodels already embedded within the program. These submodels have been derived by adapting models used by state and local agencies to perform highway planning studies. However, simplifica- tion and the use of default values have been necessary to make these models work with the type of data in HPMS; state and local agencies usually have more data available to them when they conduct project level analysis. The analyses conducted with these submodels include the following: • Travel time and travel time reliability prediction are based on Highway Capacity Manual procedures. Both business and personal travel are considered in this analysis. Costs that are considered in this type of analysis might include depending on the type of travel, value of time per person, average vehicle occupancy, vehicle capital costs, and inventory costs. • Crash prediction is based on relationships found in the safety literature. • Emission prediction is based on the Environmental Protection Agency’s MOVES model. • Vehicle operating costs are based on relationships for speed and pavement condition. They take into account fuel, motor oil, tire wear, maintenance and repair, and mileage-related depreciation. Figure H-1 illustrates the main calculations and their interrelationship within HERS.

APPENDIX H 463 In its calculations, HERS differentiates between three different types of costs: costs to both society and users (e.g., travel time), costs to society but not to users or externalities (e.g., damage due to emissions), and cost to users but not to society (e.g., fuel taxes). This differentiation is key in order to quantify the benefits of specific highway improvements, as well as predicting the behavior of users subsequent to implementation of a given improvement.4 HERS can perform three different kinds of analysis: • Analysis where the funding is constrained. HERS will compute the highway performance when highway improvements are con- strained by the available budget. • Analysis where the performance is constrained. Here HERS will provide information on the funding needed to reach a specific level of performance for the highway network under study. • Analysis where the benefit-cost ratio (BCR) is greater than a speci- fied threshold. In this case, HERS will compute both the funding and the level of system performance for the given BCR. 4 Although HERS is not a network model, it does contain a simplified procedure for ad- dressing future demand; elasticities are used to adjust traffic growth based on congestion level. FIGURE H-1 Calculation interrelationships within HERS. SOURCE: U.S. DOT 2005. Demand Elasticity

464 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM Another feature within HERS is that of a provision that allows for forcing the model to improve unacceptably deficient highway sections even if the BCR is not met. These are known as “mandatory improvements.” If this feature is not used in a given analysis, the analysis is run without man- datory improvements (this is the basic analysis). Figure H-2, captured from the HERS ST Technical Report 2005, illustrates the overall basic processes (i.e., without mandatory improvements) for runs with a minimum BCR and runs with either constrained budgets or constrained performance. Figures H-3 and H-4 illustrate the budget and performance constrained analyses when mandatory improvements are implemented. By the end of the analysis, HERS produces an extensive set of statistics that describe the estimated state of the road system under evaluation, the FIGURE H-2 Analysis process flow for runs without mandatory improvements. SOURCE: U.S. DOT 2005. APPENDIX H H-9 PREPUBLICATION COPY—Uncorrected Proofs FIGURE H-2 Analysis process flow for runs without mandatory improvements. SOURCE: U.S. DOT 2005.

APPENDIX H 465 FIGURE H-3 Analytical process for analyses for constrained funds and with man- datory improvements. SOURCE: U.S. DOT 2005. H-10 RENEWING THE NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM PREPUBLICATION COPY—Uncorrected Proofs FIGURE H-3 Analytical process for analyses for constrained funds and with mandatory improvements. SOURCE: U.S. DOT 2005.

466 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM FIGURE H-4 Analytical process for analyses for constrained performance and with mandatory improvements. SOURCE: U.S. DOT 2005. APPENDIX H H-11 PREPUBLICATION COPY—Uncorrected Proofs URE H-4 Analytical process for analyses for constrained performance and with mandatory improvements. : U.S. DOT 2 05.

APPENDIX H 467 history of each section evaluated, the costs and benefits (i.e., performance measures) of the implemented improvements, and the history of each sec- tion. HERS reports the results of the analysis in three different formats with specific focuses: System Condition format, Deficiency Reporting format, and By-Improvement-Type format. With regard to system condition, HERS produces a report that includes the following information: • A summary of the state of the system at the start of the run, • A summary of the state of the system at the end of each funding period, • A summary of how the system is predicted to change between the beginning and the end of each funding period as well as for the overall analysis period, and • Detailed information of the costs and benefits associated with the selected improvements for each funding period and for the overall analysis period. The output set of data for the three summaries (items 1 through 3 above), for example, includes the following items: • Miles in the system; • Average present serviceability rating (PSR) of pavement conditions (paved sections only); • Average international roughness index (IRI) (inches per mile, paved sections only); • Lane width; • Right-shoulder width; • Shoulder type; • Surface type; • Horizontal alignment; • Vertical alignment; • Average speed; • Peak-hour volume/capacity ratio; • Congestion delay (hours per 1,000 vehicle-miles); • Total delay (hours per 1,000 vehicle-miles); • Total VMT; • Travel-time costs (dollars per thousand vehicle-miles); • Operating costs, listed for all vehicles combined and separately for four-tire vehicles and for trucks (dollars per thousand vehicle-miles); • Crash costs (dollars per thousand vehicle-miles); • Total user costs, which is a summation of travel-time costs, oper- ating costs for all vehicles, and crash costs (dollars per thousand vehicle-miles);

468 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM • Number of crashes (per 100 million vehicle-miles); • Number of injuries (per 100 million vehicle-miles); • Number of fatalities (per 100 million vehicle miles); • Annual maintenance costs (dollars per mile); • Average cost of pollution damage (dollars per 1,000 vehicle-miles); and • Percentage of total VMT on roads not meeting the user-specified thresholds. The second format for output data is the Deficiency Summary report. This report outlines the deficiencies present in the system at the start of the funding period and the overall analysis period, as well as the effectiveness that the recommended improvements had in reducing those deficiencies. The measures reported in this report include the IRI, PSR, volume-to- capacity (V/C) ratio, lane width, shoulder width, surface type horizontal alignment, and vertical alignment. Finally, HERS produces an output file that contains the data for all the sections that HERS recommends for improvement during the funding period. The data are organized by functional class5 and improvement type. In this report, HERS includes summaries of the following: • Capital costs for all recommended improvements for each section at each funding period and for the overall analysis period, • Initial costs of preservation improvements, • Initial cost of capacity improvements, • Lane-miles improved, • Lane-miles of mandatory improvements selected on a priority basis to address unacceptable conditions, • Lane-miles of non-mandatory improvements not selected on a pri- ority basis, • Net present value of the residual value of all improvement, • Average benefit-cost ratio of recommended improvements, • Total benefits in the last year of the period, • Maintenance costs savings in the last year of the period, • User benefits in the last year of the period, • Travel time savings in the last year of the period, • Operating cost savings in the last year of the period, • Safety benefits in the last year of the period, • Crashes avoided in the last year of the period, 5 HERS considers nine functional classes of roads: rural Interstate, other rural principal arterial, rural minor arterial, rural major collector, urban interstate, other urban freeways/ expressways, other urban principal arterials, urban minor arterials, and urban collectors.

APPENDIX H 469 • Injuries avoided in the last year of the period, • Lives saved in the last year of the period, • VMT for improved sections in the last year of the period, • Emissions costs savings in the last year of the period, and • Lane-miles added to the system through widening improvements. HERS STRENGTHS AND WEAKNESSES The HERS model has both strengths and weaknesses in its application to the Future Interstate study. Its strengths include • HERS is national in scope and Interstates throughout the country can be analyzed with a consistent set of data and procedures. • HERS’s underlying data source (HPMS) is the same geometric, traf- fic, and pavement data used by state DOTs in their own investment needs analyses. Likewise, HERS’s analytical procedures are based on the same methods in widespread use by state DOTs and MPOs for needs analyses. • HERS provides insight into the tradeoffs between investment and performance, which is critical to informing investment decisions. • A state-level version of HERS has been developed and several state DOTs have used it in conducting their needs analyses. However, HERS has several limitations that need to be considered and, when possible, addressed by other means. First, improvement types in HERS are limited to pavement surface treatments or reconstruction of the top pavement layers. Safety improvements are limited to lane and shoulder widening and horizontal curve flattening. The HPMS contains no safety data related to some road features. HERS models each HPMS section individually, without regard for system effects. The model focuses on capital expenditures and user costs, and it has a long-term investment perspective consistent with the traditional federal-aid program focus. With that emphasis, the model does not address administrative costs or the cost of planning. The analyses are applied to existing facilities and do not take into account new highway alignments. HERS must use the traffic forecasts provided exogenously to calculate future demand. It therefore cannot account for shifts in demand to due changes in the network in the same way that a travel demand forecasting model does. HERS does contain a simplified procedure for addressing this issue—elasticities are used to adjust traffic growth based on congestion level. So, if an improvement reduces congestion, traffic growth will be slightly higher than it otherwise would be. However, this approach does not begin to address the issue of where the additional demand originates, or

470 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM where it goes if it is diverted. Finally, the HERS approach to project selec- tion based on strict benefit-cost analysis may not be fully representative of how agencies actually select and design projects. State and local agencies also use other criteria for selecting projects and their design, such as total cost and the impact on sustainability, the economy, and quality of life. The great variation in engineering practices and policy drivers in various regions (some would argue rooted in the funding availability for public works) can strongly influence whether the economic logic behind the HERS algorithms is accepted as a “good match” with decision making and governance goals. For all of these limitations, the analysis techniques included in HERS represent a framework that captures a large amount of future highway needs. The use of HERS is a significant improvement over the survey-based “wish lists” that have dominated many so-called “needs studies” or even the slightly more rigorous catalogues that compare current systems to en- gineering standards without regard to economic principles. At the national level, the range and scale of investment needs findings are important; and HERS is the only available methodology at that scale that is comprehensive, systematic, and peer reviewed. National Bridge Investment Analysis System NBIAS is an investment analysis software platform used to analyze fu- ture bridge investment needs and their performance. The program has historically been used to evaluate the backlog of needs, distribution of needed improvements, aggregate and user benefits, and physical measures of bridge condition, among others. Some of the questions that NBIAS can address include, for example, “what level of spending is required annually to maintain current bridge conditions over the next 20 years?” or “what user benefits might be achieved with a given set of improvement invest- ments?” To answer these questions, NBIAS simulates bridge deterioration, functional needs, traffic, and costs; and it does so for each bridge for each year in a multi-year analysis cycle. Therefore, although the principal use of NBIAS is as a network-level analysis tool, the completeness of its analysis also permits to use its results for diagnostics purposes at the bridge-level. NBIAS was designed to use the National Bridge Inventory (NBI) in- formation. The NBI is a federally mandated database of bridge inventory and condition for all bridges covered by the National Bridge Inspection Standards6 and compiled by state DOTs for submission to FHWA. The NBI has many positive features: it is a complete census of bridges so the results do not have to be extrapolated, there is little lag time between 6 The NBI database includes a thorough inventory and condition information of all bridges more than 20 feet of span in the U.S. public road system.

APPENDIX H 471 collection and availability, and the data are collected by direct observation of bridge engineers. The data are gathered through these inspections every 2 years; in some instances, however, states choose to inspect certain bridges more often. In either case, the states submit their data to the NBI on an annual basis. Because the NBI covers all bridges7 in all U.S. public roads, the NBIAS analysis results provide a complete picture of the performance and the benefit-cost analysis for bridges. NBIAS was originally developed by FHWA as a national version of the Pontis Bridge Management System.8 As such, NBIAS borrowed from the fundamental modeling structure of Pontis. Subsequently NBIAS has been improved with additional modeling methodologies from the Florida DOT. Other improvements done over time include revisions to support the integration of NBIAS results with HERS for a comprehensive highway investment needs analysis. NBIAS is composed of two modules: • The Analytical Module, which allows to create an NBIAS database from NBI files, specify technical parameters, and define and run budget scenarios, and • The “What-If” Module, which conveys the analysis results via interactive screens and reports. These can be displayed for selected scenarios. The NBIAS Analytical Module computes both preservation and func- tional improvement needs. The modeling to evaluate preservation needs aims at determining the preservation policy that best minimizes the long- term cost of maintaining each bridge element in the state of good repair. The evaluation of functional improvements includes the following actions: widening of existing lanes and shoulders, strengthening, bridge raising, and bridge replacement. The investment of functional improvement needs are calculated by ap- plying user-specified standards9 to the bridge inventory and then conducting a benefit-cost evaluation, while the investments needed for preservation are determined by applying a set of deterioration and cost models to determine the appropriate repair and rehabilitation actions while minimizing agency costs. We summarize key points about both modeling goals below. 7 The NBI covers more than 600,000 highway bridges in the U.S. public road system. 8 Licensed by the American Association of State Highway and Transportation Officials (AASHTO). 9 Standards for functional improvements include those for lane width, load rating, and verti- cal and horizontal clearances.

472 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM In order to determine whether a bridge needs a functional improve- ment, NBIAS applies two sets of business rules: • Functional improvement policies. These are based on threshold values for lane width, shoulder width, load rating, and vertical clearance. • Rules derived from calculating sufficiency ratings and structural deficiency (SD) or functionally obsolete (FO) status. Any issue that causes a bridge to be classified as SD or FO or results in a reduction of sufficiency rating also prompts a need for improvement.10 The analyst has the option of using one of these rules or both when conducting analyses. Once the possible need for improvement is identified, NBIAS evaluates if such improvement is feasible from the engineering per- spective or a last resort if complete bridge replacement is the only option. The rules for such case are specified based on the bridge SD/FO status, age, health index, and sufficiency rating. Once NBIAS evaluates the feasibility of a functional improvement or recommends a complete reconstruction, it proceeds to calculate the costs and the benefits of implementing the im- provement. The following bulleted points specify the basis for computing the benefits for specific improvements: • Widening needs are computed based on reduction of crash on the bridge, • Strengthening and raising needs are evaluated based on the reduc- tion of truck traffic detoured around the bridge, and • For bridge replacement, the benefits are based on both reduction in accidents and truck traffic detours. The reduction in life-cycle cost is also included as a benefit, since a bridge replacement restores all bridge elements to the state of best condition. Unlike functional improvements described above, bridge preservation needs are analyzed at the level of each bridge element. The NBI database, however, represents information at the bridge component-level.11 And thus, to conduct its analysis, once NBIAS imports the NBI data, it converts them 10 A couple of examples for these rules include, for instance: A deck rating in the NBI of less than 6 triggers a potential widening need, or if the bridge is located in the Strategic Highway Network and its vertical clearance is less than 4.87 meters this is identified as a vertical clear- ance deficiency and might trigger the need to raising the bridge. 11 Bridge components represent the major structural portions or units of a bridge, such as deck, superstructure, and substructure. Bridge components are composed of multiple bridge elements. For example, the superstructure is composed of a series of beams, girders, stringers, gusset plates, or other elements.

APPENDIX H 473 to element level information data, through what is called, a reverse transla- tor. The reverse translator uses a set of synthesis, quantity, and condition (SQC) models to approximate the element composition of each bridge. It then subjects each of those elements to a set of analyses using deteriora- tion algorithms and cost models for different functional improvements and preservation actions. Specifically, it uses the deterioration modeling approach12 derived from Pontis, along with optimization to determine the optimal set of improvement actions for each bridge element based on its condition. In addition to conducting calculations for each element, NBIAS adjusts for information relevant to each state using adjustment factors. The preloaded deterioration factors and costs in NBIAS are adjusted for nine different climate zones and with cost adjustment factors that are specific to each state. These costs are based on bridge replacement costs reported in the specific states. As with HERS, NBIAS recommends corrective actions based on benefit-cost analysis and to meet either specified performance metrics or a limited budget. Ultimately the goal of the benefit-cost analysis is to recommend the best improvement option that minimizes the user and agency costs over time. For every bridge analyzed, NBIAS generates a set of project alternatives that merges the results of potential preservation and functional improve- ments and screens the alternatives by BCR. The project options that are considered for recommendation are then organized by incremental BCR. At this point, NBIAS apportions funding to improvement alternatives until either the total budget is reached (if the analysis is budget-constrained13) or a minimum level for incremental BCR is achieved.14 Finally, it predicts the effect of the selected improvements on bridge conditions and the analysis cycle is then repeated by using the new bridge conditions as the starting point. The simulation period might between 1 and 50 years. As time steps (of 1 year) are taken, NBIAS allows the analyst to use either linear or ex- ponential traffic growth projections. Figure H-5 provides a schematic of the analytical process in NBIAS as illustrated in Robert and Gurenich (2008). Following this basic structure, NBIAS can perform parameterized analyses when the algorithm executes multiple analysis steps, each consisting of a simulation over time at a different budget, budget growth rate, or benefit/ cost cutoff. 12 It specifically uses Markov chain methodology for modeling bridge element deterioration. Details about the methodology can be found in Fu and Devaraj (2008). 13 In this case, the analyst must specify lower and upper limits for the annual budget. 14 When analysis is based on cutoff BCR, the analyst specifies the upper and lower limits for the cut-off BCR and the number of parametric steps. NBIAS then assumes an unlimited budget and recommends improvements until the BCR for the potential improvements fall outside of the benefit-cost limits.

474 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM FIGURE H-5 Schematic of NBIAS analytical process. SOURCE: Robert and Gurenich 2008. 304 Transportation Research Circular E-C128: International Bridge and Structure Management Conference FIGURE 1 Program simulation flowchart.

APPENDIX H 475 The output of parametric runs is a four-dimensional array of results with the following dimensions: • Measures of effectiveness, • Simulation year, • 26 bridge categories (considered from 13 functional classes of bridges either in/off the NHS or in/off the SHN), and • N+2 parametric steps. NBIAS reports analysis results for 206 measures of effectiveness (per- formance measures) that can be grouped into needs, work and backlog, benefits, BCR, NBI condition ratings, health index, sufficiency ratings, and structurally deficient/functionally obsolete bridges. Examples of measures of effectiveness reported include among others: • Investment needs—Annual recommended actions for each bridge analyzed. Reported in dollars and bridges; • Money spent; • Additional costs of postponed investments; • Work performed; • Backlog of needs—Reported in dollars and bridges; • User benefits; • Distribution of deck, superstructure, and substructure ratings; • Percentage of deficient bridge by deck area; and • Structural deficient bridges. NBIAS reports two kinds of benefits: Obtained benefits as those that are understood as occurring during the NBIAS time simulation and poten- tial benefits as those that could be attained if no budget restrictions exist. NBIAS reports the results both in graphical and tabular formats. In addition to series of reports, the modeling results can be displayed through a set of interactive views that allow interpolating results between multiple analysis steps. Pavement Health Track As mentioned in the introduction of this appendix, the PHT is an engineer- ing software tool that calculates the health of pavement networks in terms of pavements remaining service life (RSL). The software allows users to determine pavement health in terms of pavement life, ride-ability, or distress by pavement types under various environmental and administrative condi- tions, such as climate, functional classification, or rural/urban environment, on projects, corridors, and networks. PHT also offers state-of practice

476 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM maintenance options to estimate the benefits of each pavement section im- provement quantified in terms service life. To conduct its calculations, PHT uses pavement performance models that are simplified versions of the more complex mechanistic-empirical (ME) models and procedures used in the Pavement Design Guide (PDG). The PHT maintenance model allows to measure the pavement performance under a maximum BCR or under constrained funding. PHT also supports “what if” scenario analyses under various pavement design parameters, traffic, and/or terminal distresses or performance indicators. PHT calculates benefits based on the following assumptions (see Figure H-6): • Straight-line depreciation is used to depreciate individual pavement sections over their service life. • The post-treatment rate of depreciation remains the same. • The initial service life of the pavement is the sum of the current pavement age and the RSL where the current pavement age is the difference between the current year of record and the original year of construction for new pavements; or the year of last improvement for rehabilitated pavements. The PHT analysis engine receives highway data and parameter metrics and determines the pavement RSL in accordance with its implementation process presented in Figure H-7. As with HERS, the primary input relies on HPMS data with an extension for the State Pavement Management System (PMS) database. PHT also includes nationally calibrated matrix parameters FIGURE H-6 Straight-line depreciation with maintenance treatment. SOURCE: FHWA 2013b. Pavement Health rack Analysi Tool The PHT maintenance model estimates benefits of each pavement section improvement quantified in terms of the value added to the pavement infrastructure. Benefits are calculated based on the following assumptions: • Straight-line depreciation is used to depreciate individual pavement assets over their service life. • The post-treatment rate of depreciation remains the same. • The initial service life of the pavement is the sum of the current pavement age and the RSL where the current pavement age is the difference between the current year of record and the original year of construction for new pavements; or the year of last improvement for rehabilitated pavements. Straight-line depreciation, along with the effect of the application of a maintenance treatment on increasing the service life and asset value, is shown in Figure 53. Increased Value Post-Treatment Depreciation Resumed Rate Depreciation Maintenance Treatment End End Application Initial Extended Service Service Life Life Value Years Initial Service Life Revised Post Treatment Service Life Original Construction or Rehabilitation Figure 53. Straight-Line Depreciation with Maintenance Treatment The initial value of the pavement at original construction or rehabilitation is determined by the new construction costs multiplied by the adjustment factors shown in Table 14. Table 14. Initial Pavement Value Adjustment Factors Pavement Type Surface Type (Table 15) Factor New Pavement 2, 3, 4, 5 1.00 Rehabilitated Pavement, thin overlay 0.60 Rehabilitated Pavement, thick overlay 6, 7, 8, 9, 10, 11 0.60 55

APPENDIX H 477 and level 3 (policy and planning) default values that are available through ME-PDG design software. Tables H-3 and H-4 provide information on the type of improvements included in the PHT calculations for flexible, composite, and rigid pave- ments. Parameter metrics are used to control the analysis. The default parameter metrics used by the PHT analysis tool including the termi- nal thresholds, maximum service life, and default pavement estimates are FIGURE H-7 RSL forecasting process. SOURCE: FHWA 2013b. Pavement Health Track Analysis To ol Technical Information The PHT analysis engine quantifies the RSL of the pavement for each highway section using the simplified MEPDG-based pavemen t performance predicti models. The PHT analysis engine receives highway data and parameter metrics and determines the pavement RSL in accordance w ith its implementatio process presented in Figure 52. 49 Fig ure 52. RSL Forecasting Process

478 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM TABLE H-3 Feasible Improvements for Flexible and Composite (AC) Pavements Interstate Primary Secondary Surface sealing N/A N/A RSL > 5 years Rutting < 0.35 in. Cracking Length < 2,500 Cracking Percent < 5% IRI < 150 in./mi. Full depth patching with OR without grinding RSL > 10 years Rutting < 0.25 in. Cracking Length < 250 Cracking Percent < 5% IRI < 125 in./mi. RSL > 5 years Rutting < 0.25 in. Cracking Length < 1,000 Cracking Percent < 5% IRI < 150 in./mi. RSL > 5 years Rutting < 0.35 in. Cracking Length < 1,000 Cracking Percent < 5% IRI < 125 in./mi. Full depth patching with thin AC overly OR surface recycling RSL > 10 years Rutting < 0.35 in. Cracking Length < 1,000 Cracking Percent < 10% IRI < 125 in./mi. RSL > 5 years Rutting < 0.5 in. Cracking Length < 2,000 Cracking Percent < 10% IRI < 150 in./mi. N/A Major rehabilitation RSL > 3 years Rutting < 0.35 in. Cracking Length < 2,000 Cracking Percent < 15% IRI < 150 in./mi. RSL > 3 years Rutting < 0.5 in. Cracking Length < 2,000 Cracking Percent < 15% IRI < 150 in./mi. RSL > 3 years Rutting < 0.75 in. Cracking Length < 2,500 Cracking Percent < 15% IRI < 175 in./mi. New or reconstruction RSL < 3 years Rutting > 0.35 in. Cracking Length > 2,000 Cracking Percent > 15% IRI > 150 in./mi. RSL < 3 years Rutting > 0.5 in. Cracking Length > 2,000 Cracking Percent > 15% IRI > 150 in./mi. RSL < 3 years Rutting > 0.75 in. Cracking Length > 2,500 Cracking Percent > 15% IRI > 175 in./mi. SOURCE: FHWA 2013b.

APPENDIX H 479 TABLE H-4 Feasible Improvements for Rigid Pavements Interstate Primary Secondary Functional repair RSL > 10 years Cracking Percent < 10% Faulting < 0.15 in. IRI < 125 in./mi. RSL > 10 years Cracking Percent < 10% Faulting < 0.15 in. IRI < 125 in./mi. N/A Surface seals & thin overlay RSL > 10 years Cracking Percent < 1% Faulting < 0.1 in. IRI < 150 in./mi. RSL > 10 years Cracking Percent < 1% Faulting < 0.1 in. IRI < 150 in./mi. RSL > 10 years Cracking Percent < 1% Faulting < 0.1 in. IRI < 150 in./mi. Major rehabilitation RSL > 5 years Cracking Percent < 15% Faulting < 0.2 in. IRI < 175 in./mi. RSL > 5 years Cracking Percent < 15% Faulting < 0.2 in. IRI < 175 in./mi. RSL > 5 years Cracking Percent < 20% Faulting < 0.2 in. IRI < 175 in./mi. Reconstruction RSL < 5 years Cracking Percent > 15% Faulting > 0.2 in. IRI > 175 in./mi. RSL < 5 years Cracking Percent > 15% Faulting > 0.2 in. IRI > 175 in./mi. RSL < 5 years Cracking Percent > 20% Faulting > 0.2 in. IRI > 175 in./mi. SOURCE: FHWA 2013b. presented in Tables H-5 through H-7. The PHT software, however, allows the user to modify these values as needed. The primary PHT outputs are the predicted distresses by pavement types, load applications, and weighted RSL. The results are tabulated in spreadsheet, charts, or maps by pavement type, RSL group (5, 10, 15 years, etc.), geographic location, and functional class. HERS Default Parameters Input Parameters HERS and the HERS PreProcessor accept two broad types of input data:

480 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM TABLE H-5 Default Terminal Thresholds Surface Type Functional System IRI Cracking Rutting FaultingPercentage Length Rigid Interstate 170 10% 0.15 in. Primary 220 15% 0.20 in. Secondary 220 20% 0.20 in. Flexible Interstate 170 20% 640 ft./mi. 0.40 in. Primary 220 45% 800 ft./mi. 0.60 in. Secondary 220 45% 1,270 ft./mi. 0.80 in. Composite Interstate 170 100 ft./mi. Primary 220 60 ft./mi. Secondary 220 60 ft./mi. SOURCE: FHWA 2013b. TABLE H-6 Default Maximum Service Life Treatment Type Years New HMA 20 New PCC 30 Thick AC Overlay of AC Pavement 10 Thin AC Overlay of AC Pavement 6 Thick AC Overlay of PCC Pavement 10 Unbounded PCC Overlay of PCC Pavement 25 Bonded PCC Overlay of PXX Pavement 15 Thin AC Overlay of AC/PCC Pavement 6 SOURCE: FHWA 2013b. TABLE H-7 Default Pavement Estimates Pavement Estimate Category State System On Off Last Overlay Thickness 3 in. 3 in. Rigid Pavement Thickness 10 in. 10 in. Flexible Pavement Thickness 8 in. 8 in. Base Type Granular Granular Base Thickness 4 in. 4 in. Binder Type AC-40 to AC-49 AC-40 to AC-49 Dowel Bar Typically used Typically used Joint Space 20 feet 20 feet SOURCE: FHWA 2013b.

APPENDIX H 481 • Control variables—Two control files (one each for HERS and the PreProcessor) contain processing directives that are likely to be specific to an individual analysis run. These files are: – Control inputs to the PreProcessor (PPSPEC.DAT) – Control inputs to the HERS executable (RUNSPEC.DAT) • Parameter variables—Three parameter files contain data that are more likely to be unchanged between runs. These files are: – The improvement cost file (IMPRCOST.DAT) contains data items that define the costs of improving highway sections. – The deficiency level tables file (DLTBLS.DAT) defines the various condition levels that will prompt HERS to analyze a section for possible improvement. – The third parameter file (PARAMS.DAT) contains parameters covering the breadth of the HERS modelling process: the pave- ment model, operating cost components, the speed model, and the safety model, to name but a few. PreProcessor Control Inputs Tables H-8 through H-11 present the control inputs to the PreProcessor. The default values for the inputs are also presented. HERS Executable Control Inputs Tables H-12 through H-17 present the executable control inputs for HERS. The default values are also presented. Improvement Cost Input Table H-18 presents the default inputs for improvements costs in HERS. Deficiency Level Tables Input Finally, Tables H-19 through H-27 present the deficiency levels in HERS.

482 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM TABLE H-8 PreProcessor Control Inputs Control Input Description Default Value FILIN Name of HPMS data file to be preprocessed name.csv FILOUT HERS data file to be created name.HRS DSTOUT Truck VMT distribution file to be created name.DST PCTNHS_FILENAME Name of percent NHS file Blank INTYEAR_FILENAME Name of intermediate year file to be used Blank if none–for federal use only Blank DO_INTYR_MID Intermediate year middle switch specifying intermediate year to be used: • 0 = year specified • 1 = midpoint of Funding Period 1 LFP Length of funding period 5 BASEYR Base year of analysis (20xx) 16 PSRUPS PSR for unpaved sections; passed to HERS as lower limit of pavement deterioration 0.10 CALCCAP Coded capacity override switch • 0 – use coded capacities when supplied (normal case) • 1 – ignore all coded capacities 1 MAXGRW Maximum AADT growth rate in % 25 GRSWITCH Governs treatment of excessive growth rate • 1 – use default value below for every section with growth rate greater than the above maximum • 2 – interactively for every section with growth rate greater than the above maximum 1 DEFGRW Default AADT growth rate (traffic growth rate for sections whose growth rate exceeds the maximum) 25 PGTMAX Maximum percentage green time 80 PGTMIN Minimum percentage green time 20 PGTRUR Default percentage green time for principal arterials, minor arterials, and collectors, respectively 65, 50, 25 MAXR Maximum AADT/Capacity ratio 16

APPENDIX H 483 Control Input Description Default Value MRERR Report excessive AADT growth rate switch • 0 – do not report AADT over capacity exceeded MAXR • 1 – print error message for sections with AADT over capacity ratio exceeding MAXR 1 MAXTCD Maximum number of traffic control devices (stop signs and traffic signals) per mile 25 NTDERR Governs generation of traffic control device error messages • 0 – do not report average number of stop signs and traffic signals per mile exceeded MAXTCD • 1 – print warning message for sections with average number of stop signs and traffic signals per mile exceeded MAXTCD 1 MINSPL Minimum speed limit 15 MAXSPL Maximum speed limit 80 RUERR Governs generation of FC and RURURB error messages. Report inconsistent coding of RURURB • 0 = no • 1 = yes 1 AASWITCH Alignment adequacy calculation switch • 0 – use coded values for alignment adequacy only if curves and grades are not reported • 1 – use coded values for alignment adequacy whenever values are supplied 1 PSRIRI PSR/IRI indicator. When both PSR and IRI are coded: • 1 – Use PSR • 2 – Use IRI 2 OVERIDEMODE • 1 – To provide exogenously supplied improvements through the following files • 0 – Otherwise 0 TABLE H-8 Continued continued

484 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM Control Input Description Default Value STATEIN The name of the file that contains the user requested improvements. Includes CNTY and SECNUM as well improvements data. Leave the filename blank to run HERS-ST basic mode (i.e., no improvements) name.csv STATEOUT The name of the produced file that is passed to the main HERS processor name.bin OPIMPS Operational improvements control field. Each record in the file specified next will contain extra data. • 0 = don’t read • 1 = 25 fields (5v×5fps) • 2 = 30 fields (6v×5fps) • 3 = 30 fields (6v×5fps) • 4 = 55 fields (5v×11fps) 0 OPIMPSFILE Name of operational improvements file name.csv RampMeterIn Indicates input (section and Opimps files) and output (.HRS file) format of Ramp Meter fields. • 12 – format through 2012, using a single integer code • 14 – format 14 RampMeterOut Indicates input (section and Opimps files) and output (.HRS file) format of Ramp Meter fields. • 12 – format through 2012, using a single integer code • 14 – format 14 FAFFILE Name of FAF data file name.csv FAFBASEYEAR Base year for FAF data file 2005 FAFFUTYEAR Future year for FAF data file 2035 SUTCTFCT Ratio of single-unit trucks to combination trucks growth factors (FAF use only) 1.00 MAXTRKSHR Maximum truck percentage allowed on any section 0.9 BaseTrkGrSU Exogenous Demand Forecast Underlying Price Assumptions (EDFUPA) Annual Growth Rate: Single-Unit Trucks 1.01720 BaseTrkGrCM Exogenous Demand Forecast Underlying Price Assumptions (EDFUPA) Annual Growth Rate: Combination Trucks 1.01460 TABLE H-8 Continued

APPENDIX H 485 Control Input Description Default Value VOTbase EDFUPA Value of Time Adj. Factors See Table 1a FUPRIbase EDFUPA fuel price factors See Table 1b ADJVMTGR VMT growth rate adjustment control field • 1 – Yes, adjust VMT Growth Rate per data below • 0 – No, use native HPMS growth 0 VMTGRGOAL VMT goal control. Set VMT goal by • 1 – Entire System (All Functional Classifications) • 2 – Rural and Urban • 3 – Individual Functional Classifications 1 VMTINIT Initial VMT table (12 entries) See Table 1c VMT20YEAR VMT after 20 years table (12 entries) See Table 1c VMTGRINIT Initial growth rate table (12 entries) See Table 1c VMTGRTARGET Target growth rate table (12 entries) See Table 1c TABLE H-8 Continued TABLE H-9 EDFUPA Value of Time Adj. Factors FP 1 FP 2 FP 3 FP 4 FP 5 FP 6 FP 7 FP 8 FP 9 FP 10 VOTbase 1.025 1.077 1.132 1.190 1.251 1.315 1.382 1.452 1.526 1.604 TABLE H-10 EDFUPA Fuel Price Factors Funding Periods Small Auto Large Auto Pickups/ Vans 6-Tire Trucks 3-Axle Trucks 3-Axle Semi 5-Axle Semi Initial Conditions 1.000 1.000 1.000 1.000 1.000 1.000 1.000 FP 1 0.745 0.745 0.745 0.745 0.726 0.726 0.726 FP 2 0.861 0.861 0.861 0.861 0.869 0.869 0.869 FP 3 0.926 0.926 0.926 0.926 0.949 0.949 0.949 FP 4 1.007 1.007 1.007 1.007 1.048 1.048 1.048 FP 5 1.086 1.086 1.086 1.086 1.139 1.139 1.139 FP 6 1.178 1.178 1.178 1.178 1.248 1.248 1.248 FP 7 1.277 1.277 1.277 1.277 1.367 1.367 1.367 FP 8 1.385 1.385 1.385 1.385 1.497 1.497 1.497 FP 9 1.502 1.502 1.502 1.502 1.640 1.640 1.640 FP 10 1.629 1.629 1.629 1.629 1.796 1.796 1.796

486 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM TABLE H-11 PreProcessor Control Inputs—VMT Functional Classification Initial VMT VMT After 20 Years Initial Growth Rate Target Growth Rate Rural Interstate 243,918.609 342,687.938 1.01714 0.00000 Rural Other Principal Arterial 223,438.047 307,443.062 1.01609 0.00000 Rural Minor Arterial 148,438.078 195,590.938 1.01389 0.00000 Rural Major Collector 175,960.375 236,948.531 1.01499 0.00000 Urban Interstate 484,566.000 630,032.750 1.01321 0.00000 Urban Tollway 225,071.562 294,296.500 1.01350 0.00000 Urban Other Principal Arterial 455,866.250 591,690.312 1.01312 0.00000 Urban Minor Arterial 376,418.688 489,400.344 1.01321 0.00000 Urban Collector 179,698.891 238,341.797 1.01422 0.00000 All Rural 791,755.125 1,082,670.500 1.01577 0.00000 All Urban 1,721,621.375 2,243,761.750 1.01333 0.00000 All Functional Classifications 2,537,472.500 3,361,302.000 1.01416 1.01070 TABLE H-12 HERS Executable Control Inputs—RUNSPEC.DAT Control Input Description Default Value RUNNUM 20 character run identifier User Specified RUNDES 100 character run description (to appear at top of every page) Blank FILOVR Input file overwrite switch. Switch that allows HERS input data file to be overwritten while processing. • 1 – Okay to overwrite • 0 – Do not overwrite, create a copy 0 FILDEL End-state file deletion switch. Switch that allows HERS to delete file(s) describing the system(s) at the end of analysis. • 1 – Okay to delete • 0 – Do not delete 1

APPENDIX H 487 continued Control Input Description Default Value FILIN Binary section file name name.HRS DISTIN Truck VMT distribution file name name.DST INTYEAR_FILENAME Name of intermediate year file Blank LFP Length of funding period 5 NFP Number of funding periods 4 AADTTY Type of AADT calculation to perform • 1 – original method • 2 – straight line method • 3 – proposed method 2 DO_INTYEAR_MIDDLE Intermediate year selection control • 0 – use year specified in INTYEAR file • 1 – use middle of FP containing the specified year 0 INPUTLRS Long run share of elasticity –0.25 INPUTSRE Short run elasticity –0.40 DRATE Discount rate, in percentage 7.0 INL Intermediate number of lanes switch • 0 – When adding lanes, consider only increasing to the design number of lanes or not adding lanes at all • 1 – Also consider adding intermediate numbers of lanes 1 BACKLG Backlog switch • 1 – Calculate backlog at beginning of the run • 0 – Don’t calculate 0 MAXNTD Maximum number of traffic control devices (stop signs and traffic signals) per mile 25.0 BBUDGET Budget balance switch • 0 – normal run • 1 – partial balanced • 2 – fully balanced 0 REV_ITERATIONS Number of revenue iterations to perform (between 1 and 5) 5 BASEXP Base-year HERS-related capital expenditures ($M per year) 57,368 FRACVMT Fraction of excess expenditures to be covered by VMT surcharge 1.00 FRACFTX Fraction of excess expenditures to be covered by fuel tax surcharge 0.00 TABLE H-12 Continued

488 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM Control Input Description Default Value NHCIT Multiplier for non-HERS capital improvement types 1.834 Require reconstruction after number of years • 1 – Yes • 0 – No 0 Reconstruction limit: flex/comp, rigid 30, 45 SURFLIMIT Limit on consecutive resurfacing switch • 1 – limit • 0 – no limit 1 MAXSURF Maximum number of consecutive resurfacings (if limit imposed above) 2 NEEDS Full engineering needs switch • 1 – perform full engineering needs analysis • 0 – use objective specified below 1 BCRMIN Minimum BCR 1.00 OBJCTV Analytical objective • 1 – Fund constraint • 2 – Performance constraint • 3 – MinBCR at BCRMIN • 4 – Speed constraint • 5x – IRI Threshold (where “x” identifies UST) • 6x – V/C Threshold (where “x” identifies UST) • 7 – avg delay MCC 1 MCC Maintain current conditions switch (MCC ignored if OBJCTV is not 2) • 1 – Maintain current conditions at minimum improvement cost • 0 – Use goal presented below 1 LASTIMP When next improvement exceeds budget: • 0 – Split section and implement on part of section • 1 – Implement improvement and borrow from the next FP • 2 – Don’t implement and carry over funds to the next FP 0 TABLE H-12 Continued

APPENDIX H 489 continued Control Input Description Default Value CSPEC Constraint specification selector • 1 – By 9 functional classes • 2 – By principal arterial/other arterial and rural/urban • 3 – By principal arterial/other • 4 – By rural/urban • 5 – For the whole system at once 5 SCVALU Table of fund/performance constraints • Objective 1: Funds available each funding period (millions of $) • Objective 2: Highway performance goals per vehicle-mile (or per mile, if goal is for maintenance cost only)— User Costs, Total Delay, or Average IRI • Objective 3: MinBCR at BCRMIN • Objective 4: Average speed BY VMT • Objective 5x: Maximum % of IRI (by VMT/miles) above IRI Threshold (USTx in DLTBLS) • Objective 6x: Maximum % of V/C (by VMT or miles) above V/C Threshold (USTx in DLTBLS) • Objective 7: Average delay by VMT See Table 2a CWT Table of constraint weights (for OBJCTV type 2 only) See Table 2b MCUNIT Maintenance cost units. Units of specified goal: • 1 – per VMT • 2 – per mile (MCUNIT = 2 valid for: OBJCTV = 5x or 6x; or 2 if all weights other than maintenance cost are 0) 1 BCRWT Table of benefit-cost ratio weights See Table 2c OUTPUT Table of output text page selections See Table 2d SCFACT Tables of output scale factors (costs and VMT) See Table 2e Vehicle Output for VMT • 0 – 3 Vehicle Classes • 1 – 7 Vehicle Types • 2 – Total Only 1 Vehicle Output for Fuel Use • 0 – 3 Vehicle Classes • 1 – 7 Vehicle Types • 2 – Total Only 1 PPDUNITS Peak period delay units • 1 – Million hours • 2 – Thousand hours 1 TABLE H-12 Continued

490 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM Control Input Description Default Value ANDPCTC Allocate non-deficient pavement costs to capacity switch • 1 – Allocate • 0 – Allocate non-deficient costs to preservation 0 NPSEC Number of sections to be processed between printings of “number of sections processed” message • 0 – No message 10,000 NSIMP Number of improvements selected between printings of “number of selected improvements” message • 0 – No message 10,000 INMXLBCA Maximum length of benefit-cost analysis period • 0 – Default (60) 20 CAPFAC_FP Beginning FP for capacity adjustment factor • FP – to begin • 0 – to disable 0 CAPACFAC_IN Capacity adjustment factor 1.250 IN_SECOUTPUT Section output switch • 1 – Yes • 2 – No 1 CONGPRI_FP Beginning FP for congestion pricing • FP – to begin • 999 – to disable 999 CONGPRI_THR Congestion pricing V/C threshold (minimum V/C for toll) 0.80 CP_PEAK_IN Congestion Pricing Peak Switch • 0 – All day toll • 1 – Peak only 0 TARGET_REVNU_IN Target specific revenue switch • 0 – Do not use revenue targets • 1 – Use revenue targets 0 REVENUE_TARGETS Table of specific revenue targets FP 1: 135548.6 FP 2: 170297.1 FP 3: 213952.9 FP 4: 268799.9 MAX_PROC Maximum number of processors to use • 1 – default • 9 or greater – all available 1 TABLE H-12 Continued

APPENDIX H 491 TABLE H-13 RUNSPEC.DAT—Table of Fund/Performance Constraints Functional Classification FP 1 FP 2 FP 3 FP 4 FP 5 FP 6 FP 7 FP 8 FP 9 FP 10 (1) By 9 functional classes Rural Interstate a a a a a a a a a a Rural OPA a a a a a a a a a a Rural MA a a a a a a a a a a Rural Maj. Coll. a a a a a a a a a a Urban Interstate a a a a a a a a a a Urban Expwy a a a a a a a a a a Urban OPA a a a a a a a a a a Urban MA a a a a a a a a a a Urban Collector a a a a a a a a a a (2) By Princ. Art./Other and rural/urban Rural Princ. Art. a a a a a a a a a a Urban Princ. Art a a a a a a a a a a Rural Other a a a a a a a a a a Urban Other a a a a a a a a a a (3) By Princ. Art./Other Princ. Art. a a a a a a a a a a Other a a a a a a a a a a (4) By Rural/Urban Rural a a a a a a a a a a Urban a a a a a a a a a a (5) For the whole system a a a a a a a a a a NOTE: a = User-specified goal (constraint) that can be different for each cell.

492 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM TABLE H-14 RUNSPEC.DAT—Table of Constraint Weights (for OBJCTV Type 2 Only) Rural Urban Interstate OPA MA Major Collector Interstate Other Fwy/ Expy OPA MA Collector Operating Cost 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Travel Time Cost 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Property Damage 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Injury Cost 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Fatality Cost 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Number of Crashes 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Number of Injuries 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Number of Fatalities 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Maintenance Cost 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Emissions Cost 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Total Delay 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Average IRI 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

APPENDIX H 493 TABLE H-15 RUNSPEC.DAT—Table of Benefit-Cost Ratio Weights Rural Urban Interstate OPA MA Major Collector Interstate Other Fwy/ Expy OPA MA Collector Operating Cost Benefits 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Travel Time Benefits 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Property Damage Savings 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Injury Cost Savings 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Fatality Cost Savings 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Maintenance Benefits 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Residual Value 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Emissions Cost 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Upstream CO2 Damage 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Tailpipe CO2 Damage 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

494 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM TABLE H-16 RUNSPEC.DAT—Table of Output Text Page Selections Funding Period Results Complete Run Results Total initial cost of selected improvements Requested Requested Lane-miles improved Requested Requested Average BCR of selected improvements Requested Requested Total benefits in the last year of period Not Requested Not Requested Maintenance-cost savings in the last year of period Not Requested Not Requested User benefits in the last year of period Not Requested Not Requested Travel-time savings in the last year of period Not Requested Not Requested Operating-cost savings in the last year of period Not Requested Not Requested Safety benefits in the last year of period Not Requested Not Requested Crashes avoided in the last year of period Not Requested Not Requested Injuries avoided in the last year of period Not Requested Not Requested Lives saved in the last year of period Not Requested Not Requested VMT for improved sections in the last year of period Not Requested Not Requested Miles improved Requested Not Requested Capital requirement by IBCR range Not Requested Not Requested Sample sections improved by IBCR range Not Requested Not Requested Miles improved by IBCR range Not Requested Not Requested Travel-time benefits to user-benefits ratios Not Requested Not Requested Lane-miles added Requested Requested Pollution damage savings in last year of period Not Requested Not Requested Deficiencies as % of VMT Not Requested Not Requested Deficiencies as % of MILES Requested Requested Total cost of work zone delays Not Requested Not Requested

APPENDIX H 495 TABLE H-17 RUNSPEC.DAT—Tables of Output Scale Factors (Costs and VMT) Units Costs Total initial cost of selected improvements Millions of dollars Total benefits in the last year of period Millions of dollars Maintenance-cost savings in the last year of period Millions of dollars User benefits in the last year of period Millions of dollars Travel-time benefits to user-benefits ratios Millions of dollars Operating-cost savings in the last year of period Millions of dollars Safety benefits in the last year of period Millions of dollars Capital requirement by IBCR range Millions of dollars Total cost of work zone delays Millions of dollars Pollution damage savings in the last year of period Millions of dollars VMT VMT for improved sections in the last year of period Millions of vehicle-miles VMT at the beginning/end of funding period, or the difference between VMT at the beginning and the end of funding period (basic report) Millions of vehicle-miles

496 T A B L E H -1 8 Im pr ov em en t C os ts $ in T ho us an ds p er L an e- M ile R ec on st ru ct io n R es ur fa ce Sh ou ld er Im pr ov em en ts A dd L an es A lig nm en t 20 02 $ L an e W id en in g Pa ve m en t L an e W id en in g Pa ve m en t N or m al C os t H ig h C os t N or m al C os t H ig h C os t R ur al In te rs ta te Fl at 1, 18 2 77 2 66 9 27 4 51 1, 51 9 2, 10 6 2, 10 6 2, 10 6 R ol lin g 1, 32 5 79 2 77 0 29 2 84 1, 64 7 2, 66 5 2, 66 5 2, 66 5 M ou nt ai no us 2, 51 2 1, 73 4 1, 27 6 43 2 17 6 5, 12 8 6, 00 3 6, 00 3 6, 00 3 Pr in ci pa l A rt er ia ls Fl at 92 3 61 8 55 8 22 0 34 1, 21 7 1, 74 2 1, 74 2 1, 74 2 R ol lin g 1, 04 2 63 5 63 4 24 5 57 1, 30 3 2, 10 3 2, 10 3 2, 10 3 M ou nt ai no us 2, 02 4 1, 43 0 1, 22 9 34 6 75 4, 60 0 5, 29 7 5, 29 7 5, 29 7 M in or A rt er ia ls Fl at 84 4 54 3 52 0 19 5 32 1, 10 6 1, 55 3 1, 55 3 1, 55 3 R ol lin g 1, 01 9 60 1 64 7 21 0 59 1, 26 8 2, 00 0 2, 00 0 2, 00 0 M ou nt ai no us 1, 69 3 1, 11 0 1, 22 9 28 8 13 3 3, 88 3 4, 66 0 4, 66 0 4, 66 0 M aj or C ol le ct or s Fl at 88 9 57 5 53 7 19 9 41 1, 14 9 1, 55 2 1, 55 2 1, 55 2 R ol lin g 97 3 58 4 60 4 21 1 55 1, 17 4 1, 91 0 1, 91 0 1, 91 0 M ou nt ai no us 1, 47 6 91 4 87 9 28 8 85 2, 48 6 3, 24 7 3, 24 7 3, 24 7 U rb an In te rs ta te s/ E xp re ss w ay s Sm al l U rb an 1, 98 7 1, 37 9 1, 56 6 33 4 61 2, 49 3 8, 16 1 3, 36 0 11 ,4 70 Sm al l U rb an iz ed 2, 13 6 1, 38 8 1, 62 0 39 5 81 2, 72 4 8, 95 0 4, 52 9 15 ,4 61 L ar ge U rb an iz ed 3, 40 7 2, 27 2 2, 50 9 53 0 30 6 4, 55 9 15 ,2 91 6, 64 3 22 ,6 78 M aj or U rb an iz ed 6, 81 4 4, 54 4 4, 86 9 87 8 61 2 9, 11 8 38 ,0 22 13 ,2 86 50 ,8 26 Pr in ci pa l A rt er ia ls Sm al l U rb an 1, 73 2 1, 16 9 1, 43 3 28 0 62 2, 11 9 6, 92 2 2, 64 9 9, 04 1 Sm al l U rb an iz ed 1, 85 3 1, 18 3 1, 49 8 33 1 83 2, 29 6 7, 52 8 3, 26 8 11 ,1 55 L ar ge U rb an iz ed 2, 64 7 1, 73 4 2, 19 2 41 6 26 7 3, 36 0 11 ,2 26 4, 48 6 15 ,3 13 M aj or U rb an iz ed 5, 29 4 3, 46 8 4, 38 4 67 2 53 4 6, 72 0 26 ,0 49 8, 97 2 38 ,8 38 A rt er ia ls / C ol le ct or s Sm al l U rb an 1, 27 6 88 3 1, 08 4 20 5 45 1, 56 5 5, 06 9 1, 91 1 6, 52 4 Sm al l U rb an iz ed 1, 33 7 89 3 1, 09 4 23 3 55 1, 64 9 5, 35 8 2, 34 5 8, 00 5 L ar ge U rb an iz ed 1, 80 0 1, 19 4 1, 49 6 28 6 15 0 2, 28 6 7, 59 0 3, 05 2 10 ,4 17 M aj or U rb an iz ed 3, 60 0 2, 38 8 2, 26 3 47 6 30 0 4, 57 2 26 ,0 49 6, 10 4 32 ,2 35

497 T A B L E H -1 8 Im pr ov em en t C os ts $ in T ho us an ds p er L an e- M ile R ec on st ru ct io n R es ur fa ce Sh ou ld er Im pr ov em en ts A dd L an es A lig nm en t 20 02 $ L an e W id en in g Pa ve m en t L an e W id en in g Pa ve m en t N or m al C os t H ig h C os t N or m al C os t H ig h C os t R ur al In te rs ta te Fl at 1, 18 2 77 2 66 9 27 4 51 1, 51 9 2, 10 6 2, 10 6 2, 10 6 R ol lin g 1, 32 5 79 2 77 0 29 2 84 1, 64 7 2, 66 5 2, 66 5 2, 66 5 M ou nt ai no us 2, 51 2 1, 73 4 1, 27 6 43 2 17 6 5, 12 8 6, 00 3 6, 00 3 6, 00 3 Pr in ci pa l A rt er ia ls Fl at 92 3 61 8 55 8 22 0 34 1, 21 7 1, 74 2 1, 74 2 1, 74 2 R ol lin g 1, 04 2 63 5 63 4 24 5 57 1, 30 3 2, 10 3 2, 10 3 2, 10 3 M ou nt ai no us 2, 02 4 1, 43 0 1, 22 9 34 6 75 4, 60 0 5, 29 7 5, 29 7 5, 29 7 M in or A rt er ia ls Fl at 84 4 54 3 52 0 19 5 32 1, 10 6 1, 55 3 1, 55 3 1, 55 3 R ol lin g 1, 01 9 60 1 64 7 21 0 59 1, 26 8 2, 00 0 2, 00 0 2, 00 0 M ou nt ai no us 1, 69 3 1, 11 0 1, 22 9 28 8 13 3 3, 88 3 4, 66 0 4, 66 0 4, 66 0 M aj or C ol le ct or s Fl at 88 9 57 5 53 7 19 9 41 1, 14 9 1, 55 2 1, 55 2 1, 55 2 R ol lin g 97 3 58 4 60 4 21 1 55 1, 17 4 1, 91 0 1, 91 0 1, 91 0 M ou nt ai no us 1, 47 6 91 4 87 9 28 8 85 2, 48 6 3, 24 7 3, 24 7 3, 24 7 U rb an In te rs ta te s/ E xp re ss w ay s Sm al l U rb an 1, 98 7 1, 37 9 1, 56 6 33 4 61 2, 49 3 8, 16 1 3, 36 0 11 ,4 70 Sm al l U rb an iz ed 2, 13 6 1, 38 8 1, 62 0 39 5 81 2, 72 4 8, 95 0 4, 52 9 15 ,4 61 L ar ge U rb an iz ed 3, 40 7 2, 27 2 2, 50 9 53 0 30 6 4, 55 9 15 ,2 91 6, 64 3 22 ,6 78 M aj or U rb an iz ed 6, 81 4 4, 54 4 4, 86 9 87 8 61 2 9, 11 8 38 ,0 22 13 ,2 86 50 ,8 26 Pr in ci pa l A rt er ia ls Sm al l U rb an 1, 73 2 1, 16 9 1, 43 3 28 0 62 2, 11 9 6, 92 2 2, 64 9 9, 04 1 Sm al l U rb an iz ed 1, 85 3 1, 18 3 1, 49 8 33 1 83 2, 29 6 7, 52 8 3, 26 8 11 ,1 55 L ar ge U rb an iz ed 2, 64 7 1, 73 4 2, 19 2 41 6 26 7 3, 36 0 11 ,2 26 4, 48 6 15 ,3 13 M aj or U rb an iz ed 5, 29 4 3, 46 8 4, 38 4 67 2 53 4 6, 72 0 26 ,0 49 8, 97 2 38 ,8 38 A rt er ia ls / C ol le ct or s Sm al l U rb an 1, 27 6 88 3 1, 08 4 20 5 45 1, 56 5 5, 06 9 1, 91 1 6, 52 4 Sm al l U rb an iz ed 1, 33 7 89 3 1, 09 4 23 3 55 1, 64 9 5, 35 8 2, 34 5 8, 00 5 L ar ge U rb an iz ed 1, 80 0 1, 19 4 1, 49 6 28 6 15 0 2, 28 6 7, 59 0 3, 05 2 10 ,4 17 M aj or U rb an iz ed 3, 60 0 2, 38 8 2, 26 3 47 6 30 0 4, 57 2 26 ,0 49 6, 10 4 32 ,2 35

498 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM TABLE H-19 Deficiency Levels—Pavement Condition (IRI) Pavement Condition (IRI) UL RL DL UST1 UST2 UST3 R ur al Interstate Flat 250.0 190.0 65.0 120.0 95.0 170.0 Rolling 250.0 190.0 65.0 120.0 95.0 170.0 Mountainous 250.0 190.0 65.0 120.0 95.0 170.0 Principal Arterials AADT > 6,000 Flat 250.0 190.0 65.0 120.0 95.0 170.0 Rolling 250.0 190.0 65.0 120.0 95.0 170.0 Mountainous 250.0 190.0 65.0 120.0 95.0 170.0 Principal Arterials AADT < 6,000 Flat 300.0 190.0 65.0 120.0 95.0 170.0 Rolling 300.0 190.0 65.0 120.0 95.0 170.0 Mountainous 300.0 190.0 65.0 120.0 95.0 170.0 Minor Arterials AADT > 2,000 Flat 350.0 225.0 80.0 120.0 95.0 170.0 Rolling 350.0 225.0 80.0 120.0 95.0 170.0 Mountainous 350.0 225.0 80.0 120.0 95.0 170.0 Minor Arterials AADT < 2,000 Flat 350.0 225.0 80.0 120.0 95.0 170.0 Rolling 350.0 225.0 80.0 120.0 95.0 170.0 Mountainous 350.0 225.0 80.0 120.0 95.0 170.0 Major Collectors AADT > 1,000 Flat 400.0 290.0 125.0 120.0 95.0 170.0 Rolling 400.0 290.0 125.0 120.0 95.0 170.0 Mountainous 400.0 290.0 125.0 120.0 95.0 170.0 Major Collectors AADT > 400 Flat 450.0 290.0 125.0 120.0 95.0 170.0 Rolling 450.0 290.0 125.0 120.0 95.0 170.0 Mountainous 450.0 290.0 125.0 120.0 95.0 170.0 Major Collectors AADT < 400 Flat 500.0 290.0 125.0 120.0 95.0 170.0 Rolling 500.0 290.0 125.0 120.0 95.0 170.0 Mountainous 500.0 290.0 125.0 120.0 95.0 170.0 U rb an Interstate 225.0 190.0 65.0 120.0 95.0 170.0 Expressway 250.0 190.0 65.0 120.0 95.0 170.0 Princ. Arterial 275.0 190.0 65.0 120.0 95.0 170.0 Minor Arterial 400.0 225.0 80.0 120.0 95.0 170.0 Collector 450.0 290.0 125.0 120.0 95.0 170.0

APPENDIX H 499 TABLE H-20 Deficiency Levels—Surface Type Surface Type UL SDL DL UST1 R ur al Interstate Flat 2-High 2-High 2-High 2-High Rolling 2-High 2-High 2-High 2-High Mountainous 2-High 2-High 2-High 2-High Principal Arterials AADT > 6,000 Flat 2-High 2-High 2-High 2-High Rolling 2-High 2-High 2-High 2-High Mountainous 2-High 2-High 2-High 2-High Principal Arterials AADT < 6,000 Flat 3-Intermedi- ate 3-Intermedi- ate 2-High 2-High Rolling 3-Intermedi- ate 3-Intermedi- ate 2-High 2-High Mountainous 3-Intermedi- ate 3-Intermedi- ate 2-High 2-High Minor Arterials AADT > 2,000 Flat 3-Intermedi- ate 3-Intermedi- ate 3-Intermedi- ate 3-Intermedi- ate Rolling 3-Intermedi- ate 3-Intermedi- ate 3-Intermedi- ate 3-Intermedi- ate Mountainous 3-Intermedi- ate 3-Intermedi- ate 3-Intermedi- ate 3-Intermedi- ate Minor Arterials AADT < 2,000 Flat 4-Low 4-Low 3-Intermedi- ate 3-Intermedi- ate Rolling 4-Low 4-Low 3-Intermedi- ate 3-Intermedi- ate Mountainous 4-Low 4-Low 3-Intermedi- ate 3-Intermedi- ate Major Collectors AADT > 1,000 Flat 4-Low 4-Low 3-Intermedi- ate 3-Intermedi- ate Rolling 4-Low 4-Low 3-Intermedi- ate 3-Intermedi- ate Mountainous 4-Low 4-Low 3-Intermedi- ate 3-Intermedi- ate Major Collectors AADT > 400 Flat 4-Low 4-Low 4-Low 4-Low Rolling 4-Low 4-Low 4-Low 4-Low Mountainous 4-Low 4-Low 4-Low 4-Low Major Collectors AADT < 400 Flat 5-Unpaved 5-Unpaved 5-Unpaved 5-Unpaved Rolling 5-Unpaved 5-Unpaved 5-Unpaved 5-Unpaved Mountainous 5-Unpaved 5-Unpaved 5-Unpaved 5-Unpaved continued

500 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM TABLE H-20 Continued Surface Type UL SDL DL UST1 U rb an Interstate 2-High 2-High 2-High 2-High Expressway 2-High 2-High 2-High 2-High Princ. Arterial 3-Inter- mediate 3-Inter- mediate 2-High 2-High Minor Arterial 4-Low 4-Low 3-Interme- diate 3-Interme- diate Collector 5-Unpaved 5-Unpaved 4-Low 4-Low TABLE H-21 Deficiency Levels—V/C Ratio V/C Ratio UL SDL DL WS UST1 UST2 R ur al Interstate Flat 0.90 0.85 0.60 0.70 0.70 0.80 Rolling 0.95 0.90 0.70 0.80 0.70 0.80 Mountainous 0.98 0.95 0.70 0.90 0.70 0.80 Principal Arterials AADT > 6,000 Flat 0.90 0.85 0.60 0.70 0.70 0.80 Rolling 0.95 0.90 0.70 0.80 0.70 0.80 Mountainous 0.98 0.95 0.70 0.90 0.70 0.80 Principal Arterials AADT < 6,000 Flat 0.90 0.85 0.60 0.70 0.70 0.80 Rolling 0.95 0.90 0.70 0.80 0.70 0.80 Mountainous 0.98 0.95 0.70 0.90 0.70 0.80 Minor Arterials AADT > 2,000 Flat 0.90 0.85 0.60 0.70 0.70 0.80 Rolling 0.95 0.90 0.70 0.80 0.70 0.80 Mountainous 0.98 0.95 0.70 0.90 0.70 0.80 Minor Arterials AADT < 2,000 Flat 0.90 0.85 0.60 0.70 0.70 0.80 Rolling 0.95 0.90 0.70 0.80 0.70 0.80 Mountainous 0.98 0.95 0.70 0.90 0.70 0.80 Major Collectors AADT > 1,000 Flat 0.90 0.85 0.60 0.70 0.70 0.80 Rolling 0.95 0.90 0.70 0.80 0.70 0.80 Mountainous 0.98 0.95 0.70 0.90 0.70 0.80 Major Collectors AADT > 400 Flat 1.00 1.00 0.70 0.95 0.70 0.80 Rolling 1.00 1.00 0.70 0.95 0.70 0.80 Mountainous 1.00 1.00 0.70 0.95 0.70 0.80 Major Collectors AADT < 400 Flat 1.00 1.00 0.70 1.00 0.70 0.80 Rolling 1.00 1.00 0.70 1.00 0.70 0.80 Mountainous 1.00 1.00 0.70 1.00 0.70 0.80

APPENDIX H 501 Surface Type UL SDL DL WS UST1 UST2 U rb an Interstate 0.98 0.95 0.70 0.90 0.70 0.80 Expressway 0.98 0.95 0.70 0.90 0.70 0.80 Princ. Arterial 0.98 0.95 0.70 0.90 0.70 0.80 Minor Arterial 0.98 0.95 0.70 0.90 0.70 0.80 Collector 0.98 0.95 0.70 0.90 0.70 0.80 TABLE H-21 Continued TABLE H-22 Deficiency Levels—Lane Width Lane Width (ft) UL SDL DL UST1 R ur al Interstate Flat 11 11 12 12 Rolling 11 11 12 12 Mountainous 11 11 12 12 Principal Arterials AADT > 6,000 Flat 10 11 12 12 Rolling 10 11 12 12 Mountainous 10 11 12 12 Principal Arterials AADT < 6,000 Flat 10 11 12 12 Rolling 10 11 12 12 Mountainous 10 11 12 12 Minor Arterials AADT > 2,000 Flat 8 9 12 12 Rolling 8 9 12 12 Mountainous 8 9 12 12 Minor Arterials AADT < 2,000 Flat 8 9 12 12 Rolling 8 9 12 12 Mountainous 8 9 12 12 Major Collectors AADT > 1,000 Flat 8 9 12 12 Rolling 8 9 12 12 Mountainous 8 9 12 12 Major Collectors AADT > 400 Flat 8 8 11 11 Rolling 8 8 11 11 Mountainous 8 8 11 11 Major Collectors AADT < 400 Flat 8 8 10 10 Rolling 8 8 10 10 Mountainous 8 8 10 10 continued

502 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM Lane Width (ft) UL SDL DL UST1 U rb an Interstate 11 11 12 12 Expressway 10 11 12 12 Princ. Arterial 9 10 12 12 Minor Arterial 8 8 12 12 Collector 8 8 12 12 TABLE H-22 Continued TABLE H-23 Deficiency Levels—Right Shoulder Width Right Shoulder Width (ft) UL SDL DL UST1 R ur al Interstate Flat 6 7 10 10 Rolling 6 7 9 9 Mountainous 6 6 7 7 Principal Arterials AADT > 6,000 Flat 6 7 9 9 Rolling 6 7 9 9 Mountainous 6 6 7 7 Principal Arterials AADT < 6,000 Flat 6 7 9 9 Rolling 6 7 9 9 Mountainous 6 6 7 7 Minor Arte- rials AADT > 2,000 Flat 6 6 7 7 Rolling 6 6 7 7 Mountainous 4 4 6 6 Minor Arte- rials AADT < 2,000 Flat 4 5 7 7 Rolling 4 5 7 7 Mountainous 4 4 6 6 Major Collectors AADT > 1,000 Flat 2 3 6 6 Rolling 2 3 6 6 Mountainous 2 3 6 6 Major Collectors AADT > 400 Flat 0 0 4 4 Rolling 0 0 4 4 Mountainous 0 0 4 4 Major Collectors AADT < 400 Flat 0 0 2 2 Rolling 0 0 2 2 Mountainous 0 0 2 2

APPENDIX H 503 Right Shoulder Width (ft) UL SDL DL UST1 U rb an Interstate 6 7 9 9 Expressway 6 7 9 9 Princ. Arterial 0 5 8 8 Minor Arterial 0 5 8 8 Collector 0 3 6 6 TABLE H-23 Continued TABLE H-24 Deficiency Levels—Shoulder Type Shoulder Type UL SDL DL UST1 R ur al Interstate Flat 2-Stabilized 2-Stabilized 2-Stabilized 2-Stabilized Rolling 2-Stabilized 2-Stabilized 2-Stabilized 2-Stabilized Mountainous 2-Stabilized 2-Stabilized 2-Stabilized 2-Stabilized Principal Arterials AADT > 6,000 Flat 2-Stabilized 2-Stabilized 2-Stabilized 2-Stabilized Rolling 2-Stabilized 2-Stabilized 2-Stabilized 2-Stabilized Mountainous 2-Stabilized 2-Stabilized 2-Stabilized 2-Stabilized Principal Arterials AADT < 6,000 Flat 3-Earth 2-Stabilized 2-Stabilized 2-Stabilized Rolling 3-Earth 2-Stabilized 2-Stabilized 2-Stabilized Mountainous 3-Earth 2-Stabilized 2-Stabilized 2-Stabilized Minor Arte- rials AADT > 2,000 Flat 3-Earth 2-Stabilized 2-Stabilized 2-Stabilized Rolling 3-Earth 2-Stabilized 2-Stabilized 2-Stabilized Mountainous 3-Earth 2-Stabilized 2-Stabilized 2-Stabilized Minor Arte- rials AADT < 2,000 Flat 3-Earth 3-Earth 3-Earth 3-Earth Rolling 3-Earth 3-Earth 3-Earth 3-Earth Mountainous 3-Earth 3-Earth 3-Earth 3-Earth Major Collectors AADT > 1,000 Flat 3-Earth 3-Earth 3-Earth 3-Earth Rolling 3-Earth 3-Earth 3-Earth 3-Earth Mountainous 3-Earth 3-Earth 3-Earth 3-Earth Major Collectors AADT > 400 Flat 4-Curbed 3-Earth 3-Earth 3-Earth Rolling 4-Curbed 3-Earth 3-Earth 3-Earth Mountainous 4-Curbed 3-Earth 3-Earth 3-Earth Major Collectors AADT < 400 Flat 4-Curbed 3-Earth 3-Earth 3-Earth Rolling 4-Curbed 3-Earth 3-Earth 3-Earth Mountainous 4-Curbed 3-Earth 3-Earth 3-Earth continued

504 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM TABLE H-24 Continued Shoulder Type UL SDL DL UST1 U rb an Interstate 1-Surfaced 1-Surfaced 1-Surfaced 1-Surfaced Expressway 1-Surfaced 1-Surfaced 1-Surfaced 1-Surfaced Princ. Arterial 4-Curbed 2-Stabilized 2-Stabilized 2-Stabilized Minor Arterial 4-Curbed 3-Earth 3-Earth 3-Earth Collector 4-Curbed 3-Earth 3-Earth 3-Earth TABLE H-25 Deficiency Levels—Horizontal Alignment Horizontal Alignment UL SDL DL R ur al Interstate Flat 2-All Curves Accept 2-All Curves Accept 1-All Crv Appropriate Rolling 2-All Curves Accept 2-All Curves Accept 1-All Crv Appropriate Mountainous 2-All Curves Accept 2-All Curves Accept 1-All Crv Appropriate Principal Arterials AADT > 6000 Flat 2-All Curves Accept 2-All Curves Accept 1-All Crv Appropriate Rolling 2-All Curves Accept 2-All Curves Accept 1-All Crv Appropriate Mountainous 2-All Curves Accept 2-All Curves Accept 1-All Crv Appropriate Principal Arterials AADT < 6000 Flat 3-Some Red. Speed 2-All Curves Accept 2-All Curves Accept Rolling 3-Some Red. Speed 2-All Curves Accept 2-All Curves Accept Mountainous 3-Some Red. Speed 2-All Curves Accept 2-All Curves Accept Minor Arterials AADT > 2000 Flat 3-Some Red. Speed 2-All Curves Accept 2-All Curves Accept Rolling 3-Some Red. Speed 2-All Curves Accept 2-All Curves Accept Mountainous 3-Some Red. Speed 2-All Curves Accept 2-All Curves Accept

APPENDIX H 505 TABLE H-25 Continued Horizontal Alignment UL SDL DL R ur al Minor Arterials AADT < 2000 Flat 3-Some Red. Speed 2-All Curves Accept 2-All Curves Accept Rolling 3-Some Red. Speed 2-All Curves Accept 2-All Curves Accept Mountainous 3-Some Red. Speed 2-All Curves Accept 2-All Curves Accept Major Collectors AADT > 1000 Flat 3-Some Red. Speed 2-All Curves Accept 2-All Curves Accept Rolling 3-Some Red. Speed 2-All Curves Accept 2-All Curves Accept Mountainous 3-Some Red. Speed 2-All Curves Accept 2-All Curves Accept Major Collectors AADT > 400 Flat 4-Significant Curves 3-Some Red. Speed 2-All Curves Accept Rolling 4-Significant Curves 3-Some Red. Speed 2-All Curves Accept Mountainous 4-Significant Curves 3-Some Red. Speed 2-All Curves Accept Major Collectors AADT < 400 Flat 4-Significant Curves 3-Some Red. Speed 2-All Curves Accept Rolling 4-Significant Curves 3-Some Red. Speed 2-All Curves Accept Mountainous 4-Significant Curves 3-Some Red. Speed 2-All Curves Accept U rb an Interstate 2-All Curves Accept 2-All Curves Accept 1-All Crv Appropriate Expressway 2-All Curves Accept 2-All Curves Accept 1-All Crv Appropriate Princ. Arterial 3-Some Red. Speed 2-All Curves Accept 1-All Crv Appropriate Minor Arterial — — — Collector — — —

506 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM TABLE H-26 Deficiency Levels—Vertical Alignment Vertical Alignment UL SDL DL R ur al Interstate Flat 2-All Grades Accept 2-All Grades Accept 1-All Grd Appropriate Rolling 2-All Grades Accept 2-All Grades Accept 1-All Grd Appropriate Mountainous 2-All Grades Accept 2-All Grades Accept 1-All Grd Appropriate Principal Arterials AADT > 6,000 Flat 2-All Grades Accept 2-All Grades Accept 1-All Grd Appropriate Rolling 2-All Grades Accept 2-All Grades Accept 1-All Grd Appropriate Mountainous 2-All Grades Accept 2-All Grades Accept 1-All Grd Appropriate Principal Arterials AADT < 6,000 Flat 3-Some Red. Speed 2-All Grades Accept 2-All Grades Accept Rolling 3-Some Red. Speed 2-All Grades Accept 2-All Grades Accept Mountainous 3-Some Red. Speed 2-All Grades Accept 2-All Grades Accept Flat 3-Some Red. Speed 2-All Grades Accept 2-All Grades Accept Rolling 3-Some Red. Speed 2-All Grades Accept 2-All Grades Accept Mountainous 3-Some Red. Speed 2-All Grades Accept 2-All Grades Accept Minor Arterials AADT < 2,000 Flat 3-Some Red. Speed 2-All Grades Accept 2-All Grades Accept Rolling 3-Some Red. Speed 2-All Grades Accept 2-All Grades Accept Mountainous 3-Some Red. Speed 2-All Grades Accept 2-All Grades Accept Major Collectors AADT > 1,000 Flat 3-Some Red. Speed 2-All Grades Accept 2-All Grades Accept Rolling 3-Some Red. Speed 2-All Grades Accept 2-All Grades Accept Mountainous 3-Some Red. Speed 2-All Grades Accept 2-All Grades Accept

APPENDIX H 507 Vertical Alignment UL SDL DL R ur al Major Collectors AADT > 400 Flat 4-Significant Grades 3-Some Red. Speed 2-All Grades Accept Rolling 4-Significant Grades 3-Some Red. Speed 2-All Grades Accept Mountainous 4-Significant Grades 3-Some Red. Speed 2-All Grades Accept Major Collectors AADT < 400 Flat 4-Significant Grades 3-Some Red. Speed 2-All Grades Accept Rolling 4-Significant Grades 3-Some Red. Speed 2-All Grades Accept Mountainous 4-Significant Grades 3-Some Red. Speed 2-All Grades Accept U rb an Interstate — — — Expressway — — — Princ. Arterial — — — Minor Arterial — — — Collector — — — TABLE H-26 Continued

508 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM TABLE H-27 Design Standards Design Standards Surface Type Lane Width Right Shoulder Width Curve Grade Median Width R ur al Interstate Flat 2-High 12 12 1-All Crv Appr 0.70 64 Rolling 2-High 12 10 1-All Crv Appr 0.70 64 Moun- tainous 2-High 12 8 3-Some Red. Speed 0.70 16 Principal Ar- terials AADT > 6,000 Flat 2-High 12 10 1-All Crv Appr 0.70 40 Rolling 2-High 12 10 1-All Crv Appr 0.70 40 Moun- tainous 2-High 12 8 3-Some Red. Speed 0.70 16 Principal Ar- terials AADT < 6,000 Flat 2-High 12 10 1-All Crv Appr 0.70 40 Rolling 2-High 12 10 2-All Crv Accept 0.70 40 Moun- tainous 2-High 12 8 3-Some Red. Speed 0.70 16 Minor Arteri- als AADT > 2,000 Flat 2-High 12 8 1-All Crv Appr 0.70 40 Rolling 2-High 12 8 2-All Crv Accept 0.70 40 Moun- tainous 2-High 12 8 3-Some Red. Speed 0.70 16 Minor Arteri- als AADT < 2,000 Flat 3-Interm 12 8 1-All Crv Appr 0.70 0 Rolling 3-Interm 12 8 2-All Crv Accept 0.70 0 Moun- tainous 3-Interm 12 6 3-Some Red. Speed 0.70 0 Major Collec- tors AADT > 1,000 Flat 3-Interm 12 8 2-All Crv Accept 0.70 16 Rolling 3-Interm 12 8 3-Some Red. Speed 0.70 16 Moun- tainous 3-Interm 12 6 4-Significant Curves 0.70 16

APPENDIX H 509 Design Standards Surface Type Lane Width Right Shoulder Width Curve Grade Median Width R ur al Major Collec- tors AADT > 400 Flat 4-Low 11 4 2-All Crv Accept 0.70 0 Rolling 4-Low 11 4 3-Some Red. Speed 0.70 0 Moun- tainous 4-Low 11 4 4-Significant Curves 0.70 0 Major Collec- tors AADT < 400 Flat 4-Low 10 2 2-All Crv Accept 0.70 0 Rolling 4-Low 10 2 3-Some Red. Speed 0.70 0 Moun- tainous 4-Low 10 2 4-Significant Curves 0.70 0 Design Standards Surface Type Lane Width Right Shoulder Width Curve Grade Median Width U rb an Inter- state 2-High 12 10 3-Some Red. Speed — 20 Express- way 2-High 12 10 3-Some Red. Speed — 20 Princ. Arterial 2-High 12 9 3-Some Red. Speed — — Minor Arterial 2-High 12 9 — — — Collec- tor 3-Interm 12 8 — — — TABLE H-27 Continued

510 NATIONAL COMMITMENT TO THE INTERSTATE HIGHWAY SYSTEM REFERENCES Abbreviations FHWA Federal Highway Administration FTA Federal Transit Administration U.S. DOT U.S. Department of Transportation Coley, N. n.d. The Silver Bullet: How to Use the National Bridge Investment Analysis to De- velop Bridge Targets and Risk-Based Asset Management Plans. FHWA, Washington, D.C. http://onlinepubs.trb.org/onlinepubs/conferences/2016/AssetMgt/67.NathanielColey.pdf. Coley, N., and M. M. Lwin. 2014. Another Bridge Life-Cycle Cost Analysis Tool for MAP- 21. ASPIRE, Winter. http://aspirebridge.com/magazine/2014Winter/FHWA_Win14_Web. pdf. FHWA. 2013a. Enhancement of the Pavement Health Track (PHT) Analysis Tool—Final Report. https://www.fhwa.dot.gov/pavement/healthtrack/pubs/technical/technical.pdf. FHWA. 2013b. Pavement Health Track (PHT) Analysis Tool Graphical User Interface: User’s Manual, Version 2.x. https://www.fhwa.dot.gov/pavement/healthtrack/pubs/users/users. pdf. FHWA and FTA. 2016. Appendix B: Bridge Investment Analysis Methodology. In 2015 Status of the Nation’s Highway, Bridges, and Transit: Conditions and Performance: Re- port to Congress. U.S. DOT, Washington, D.C. Pp. B1–B-7. https://www.fhwa.dot.gov/ policy/2015cpr/pdfs/appendixb.pdf. Fu, G., and D. Devaraj. 2008. Methodology of Homogeneous and Non-Homogeneous Markov Chains for Modelling Bridge Element Deterioration. https://www.michigan. gov/documents/mdot/MDOT_Research_Report_RC1520_257991_7.pdf. Robert, W., and D. Gurenich. 2008. Modeling Approach of the National Bridge Investment 8 Analysis System. In Transportation Research Circular E-C128: Tenth International Con- ference on Bridge and Structure Management. Transportation Research Board, Washing- ton, D.C. http://onlinepubs.trb.org/onlinepubs/circulars/ec128.pdf. Robert, W., and S. Sissel. n.d. Modeling of Life Cycle Alternatives in the National Bridge Investment Analysis System. https://www.eiseverywhere.com/file_uploads/85251f592cd a269ce7938df36bcb3b90_RobertWilliam.pdf. U.S. DOT. 2005. HERS ST Technical Report. U.S. DOT, Washington, D.C.

Next: Appendix I: Case Studies »
Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future Get This Book
×
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

TRB Special Report 329: Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future explores pending and future federal investment and policy decisions concerning the federal Interstate Highway System. Congress asked the committee to make recommendations on the “features, standards, capacity needs, application of technologies, and intergovernmental roles to upgrade the Interstate System” and to advise on any changes in law and resources required to further the recommended actions. The report of the study committee suggests a path forward to meet the growing and shifting demands of the 21st century.

The prospect of an aging and worn Interstate System that operates unreliably is concerning in the face of a vehicle fleet that continues to transform as the 21st century progresses and the vulnerabilities due to climate change place new demands on the country’s transportation infrastructure. Recent combined state and federal capital spending on the Interstates has been about $20–$25 billion per year. The estimates in this study suggest this level of spending is too low and that $45–$70 billion annually over the next 20 years will be needed to undertake the long-deferred rebuilding of pavements and bridges and to accommodate and manage growing user demand. This estimated investment is incomplete because it omits the spending that will be required to meet other challenges such as boosting the system’s resilience and expanding its geographic coverage.

The committee recommends that Congress legislate an Interstate Highway System Renewal and Modernization Program (RAMP). This program should focus on reconstructing deteriorated pavements, including their foundations, and bridge infrastructure; adding physical capacity and operations and demand management capabilities where needed; and increasing the system’s resilience. The report explores ways to pay for this program, including lifting the ban on tolling of existing general-purpose Interstate highways and increasing the federal fuel tax to a level commensurate with the federal share of the required RAMP investment.

View the videos, recorded webcast, graphics, summary booklet, press release, and highlights page at interstate.trb.org.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  6. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  7. ×

    View our suggested citation for this chapter.

    « Back Next »
  8. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!