U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
202-366-4000
Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
| SUMMARY REPORT |
| This summary report is an archived publication and may contain dated technical, contact, and link information |
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| Publication Number: FHWA-HRT-17-038 Date: February 2018 |
Publication Number: FHWA-HRT-17-038 Date: February 2018 |
In 2009, the FHWA Exploratory Advanced Research (EAR) Program began investigating the use of agent-based modeling and simulation (ABMS) for characterizing driver and traveler behavior. To date, FHWA has sponsored three projects investigating this topic: (1) Driver Behavior in Traffic (Virginia Tech, 2009), (2) Evolutionary Agent System for Transportation Outlook (University of Arizona, 2011), and (3) Agent-Based Approach for Integrated Driver and Traveler Behavior Modeling (University of Maryland, 2011).(32–34) ABMS is a computational modeling approach for simulating the actions and interactions of autonomous individuals. ABMS has been used in many research domains; however, little is known about its applicability to highway research.
The evaluation team will evaluate EAR ABMS activities to assess their effectiveness in meeting intended goals and outcomes. This evaluation aims to understand the effect of FHWA R&T activities on the implementation of the agent-based approaches on transportation-related projects and activities.
For this evaluation, analysis will be primarily qualitative in nature. Interviews as well as document and literature reviews will provide the majority of the necessary data. Document review and citation analysis will include EAR-funded and FHWA research products, other ABMS research, and partner and research community outputs. Interviews will supplement the document record with program, stakeholder, and research community assessments of the quality and impact of FHWA research.
Finding: Confusion exists regarding the nomenclature and definition of ABMS.
While the EAR program refers to “agent-based modeling and simulation” as “ABMS,” others in the industry refer to the practice as “AgBM.” In addition, there is evidence of confusion regarding what constitutes an agent-based model, specifically the learning and interaction elements, compared to simulation models that simply incorporate individual actors.
Finding: ABMS may serve as a natural next step combining activity-based models and dynamic traffic assignment models.
The transportation industry primarily uses two forms of traffic models: activity-based models (ABM), which focus on travelers, and dynamic traffic assignment (DTA) models, which focus on the transportation network. These practices have been integrated by some practitioners to create ABM-DTA models. ABMS models could inform and enhance ABM-DTA models moving forward.
The evaluation team has completed evaluation planning and is currently collecting data and conducting interviews of relevant stakeholders. This included attending the TRB-sponsored Innovation in Travel Modeling conference. The draft final report will be delivered in March 2017.
eNEPA is an online workspace and collaboration forum for major projects requiring an environmental impact statement (EIS) or an environmental assessment.(35) Since the Transportation Equity Act for the 21st Century, a central focus of FHWA efforts to accelerate project delivery has been to establish coordinated environmental review processes with concurrent interagency reviews and established time periods.(36) FHWA developed eNEPA for State transportation departments to use in support of interagency reviews with the intent of creating a transparent and streamlined process across States and transportation projects. The tool was rolled out nationally in August 2013.
This evaluation will seek to understand the breadth and depth of use of eNEPA (i.e., users, types of projects, goals), usability of the tool (including additional desired features), effects on the project environmental timeline(reductions in overall review time), and impacts on interagency collaboration(i.e., timing, quantity, and quality of collaboration).
The team will collect data through interviews with FHWA Office of Project Development and Environmental Review program staff members, staff members from up to nine State transportation departments using eNEPA, and up to nine State transportation departments not using eNEPA. Quantitative data collection will include—to the extent availability allows—eNEPA statistics on users, projects, and milestone completion dates (i.e., notice of intent, draft EIS, final EIS, record of decision).
Finding: The tool’s lack of flexibility, particularly in terms of its process flow and document review features, greatly limits its overall usefulness.
As of December 2015, only one State transportation department was actively using eNEPA as part of the environmental review process for an EIS project. Other agencies piloted eNEPA but stopped using the tool because of institutional and technological issues. Interviewees identified many recommendations for improving the usability of eNEPA and the user experience. In 2016, FHWA updated the tool to incorporate many of the recommendations.
An interim technical memo that summarized the data collection and key findings from the first year of the evaluation was delivered in January 2016 and will be updated in January 2017. Evaluation activities will culminate in a draft report to be delivered in March 2018.
GRS technology consists of layers of geosynthetic textile and compacted granular fill. The U.S. Forest Service first used GRS to build walls for roads in mountain terrain in the 1970s. The Infrastructure R&D team further developed the technology into the GRS-IBS, which is intended to be easy to design, inexpensive, and fast to construct with readily available labor, materials, and equipment. The GRS-IBS team published the Geosynthetic Reinforced Soil Integrated Bridge System Interim Implementation Guide in 2011 and results from load testing in 2013.(39) EDC has featured the technology since the initiative’s first year.
The evaluation team is conducting a retrospective evaluation of GRS-IBS research, disseminating the results (including through EDC), and developing a path to market acceptance. After reviewing a draft evaluation report in November 2015, the team at TFHRC and other stakeholders requested that evaluators delve deeper into barriers to deployment. The evaluation team was asked to consider whether the concept of a disruptive technology might help to explain these barriers.
The evaluation relies on more than 35 semi-structured interviews with representatives from State, county, and tribal governments; FHWA departments; AASHTO; and the private sector. The evaluation team developed a schema for formal coding of interview transcripts based on both FHWA’s evaluation needs and the diversity of interviewee responses. The evaluation team also analyzed a spreadsheet of completed GRS-IBS bridges provided by FHWA and the National Bridge Inventory to better understand the technology’s trajectory and current place in the market by tracking the frequency, relative share, and geographic context of construction.
Finding: FHWA efforts fostered positive attitudes toward GRS-IBS and more market share during the 2010–2015 period.
Nineteen interviewees reported a shift in the attitude of potential deployers toward GRS-IBS. Analysis of available data on single span bridges under 140 ft long showed a considerable increase in GRS-IBS deployments in percentage terms from 2010–2015 compared with 2005–2009, primarily for bridges in the 50–110-ft range. For example, between 2005–2009, no GRS-IBS bridges were built in the 90–100-ft range. Between 2010 and 2015, 6 out of 6 (100 percent) of the bridges built in the 90–100-ft range used GRS-IBS.
Finding: Internal disagreements, including between geotechnical engineers and hydrologic engineers, led users to receive conflicting information.
Ten interviewees, both geotechnical and hydrologic engineers, felt that hydrologic engineers did not become involved in GRS-IBS until late in the research process. They expressed concerns even after FHWA officially started to promote the technology. One hydrologic engineer said that his colleagues, “thought if they ignored it [GRS-IBS], it would go away.” Potential deployers ended up receiving different messages depending to whom they spoke.
In March 2016, the evaluation team commenced work on an expansion of the GRS-IBS Draft Evaluation Report. The team delivered a Final Task Management Plan in July 2016. Delivery of the draft expanded report is expected in December 2016. The final report is expected in March 2017.
FHWA high-friction surface treatments (HFST) research began as part of a larger effort to evaluate a range of surface improvements designed to increase road safety. HFST involve the overlay of calcined bauxite on a base of epoxy along portions of roadways that are susceptible to vehicle slippage (e.g., under precipitation or in curves with inoptimal superelevation). The calcined bauxite supports the grip of tires along the road by inhibiting the formation of a plane of water between the road and tires. The FHWA HFST project culminated in the 2014 report, Evaluation of Pavement Safety Performance (EPSP).(38) The report supports the use of HFST to improve safety, although the findings were constrained by limitations in the data and method. Ongoing research on developing crash modification factors (CMFs) will be published in the CMF Clearinghouse and Interactive Highway Safety Design Manual.(39) Intended outcomes of the EPSP and associated outreach include the establishment of accepted CMFs, support for HFST as a road-improvement alternative through increased adoption by State and local transportation agencies, and inclusion of HFST as both a safety and pavement feature in pavement-design and roadway-design guides.
The evaluation will focus on FHWA’s contribution to HFST research and technical guides, the role of the research and publications in changing stakeholders’ awareness and attitudes, and the intended outcomes of the establishment of accepted CMFs. This includes use of HFST in industry-standard publications and adoption of HFST by State and local decisionmakers.
The evaluation team has developed evaluation criteria, measures of effectiveness, data inputs, and preferred data sources for each evaluation area. Analysis will be primarily qualitative in nature. Interviews as well as document and literature reviews will provide the majority of the necessary data. Primary data sources will include interviews and key planning and strategic documentation (e.g., transportation meeting proceedings, HSIP reports, and State and MPO materials (design manuals, SHSPs, Transportation Improvement Programs)), as well as outputs from ongoing projects. The evaluation team will also access materials from the CMF Clearinghouse.(40) To assess the extent to which FHWA HFST-related research is likely to influence the attitude of the transportation community toward HFST as a safety countermeasure, the evaluation team will identify evidence of confidence in HFST among State and local decisionmakers and transportation practitioners. Assessing the impact of R&T research on HFST adoption will rely on changes in the number of HFST projects relative to competing countermeasures. Evaluators will also gauge the incremental safety impact of R&T HFST research.
The final evaluation plan was completed in July 2015 and updated to incorporate changes to the scope based on developments in the project and to harmonize with parallel HFST research on the development of CMFs. The evaluation team is collecting preliminary data and planning for ongoing data collection. The draft report for this prospective evaluation is scheduled for October 2018.
The use of recycled materials, including reclaimed asphalt pavement (RAP) and reclaimed asphalt shingles (RAS), reduces both the amount of new materials required for asphalt mixes and the amount of material going to landfills. At the same time, use of warm-mix asphalt (WMA) technologies is growing, enabling producers of asphalt pavement to lower the temperatures at which the material is mixed and placed on the road, resulting in reductions in energy consumption and emissions. FHWA is conducting accelerated load facility and laboratory testing of WMA to determine RAP/RAS limits and binder performance–grade needs. FHWA will provide states with performance-based specifications for testing mix designs that utilize RAP/RAS. The TFHRC Infrastructure Materials team makes its dataset and core samples available to researchers in other organizations.
The evaluation team will evaluate both the research process and research products of the FHWA R&T project, Advance Use of Recycled Asphalt in Flexible Pavement Infrastructure: Develop and Deploy Framework for Proper Use and Evaluation of Recycled Asphalt in Asphalt Mixtures.(41) The team identified four research areas, each with specific research questions; the four research areas include the following: research selection process, the evolution of the research design, collaboration with other organizations, and initial acceptance of the FHWA research report.
This evaluation is qualitative in nature and will use literature searches, document reviews, and qualitative interviews with FHWA staff and members of the asphalt research community (e.g., members of the Expert Task Group).
Finding: The significant outreach conducted by the research team has increased the value of the research.
FHWA solicited (and/or stakeholders offered) input regarding several key areas of the experimental design. By incorporating stakeholder feedback, the interviewees indicated that both the quality and the usability of the research product has been strengthened.
Finding: Collaboration results in more efficient use of resources for both FHWA and the collaborating partners.
FHWA has limited resources and cannot perform all the tests that it might prefer on the sample materials. By sharing samples, however, FHWA enables other organizations to perform their own tests and to validate FHWA results, resulting in a more efficient use of resources within the asphalt community.
The evaluation team delivered its Interim Technical Memorandum in June 2016 and its Data Acceptability Memorandum in August 2016. Anticipated dates for other key deliverables include a second Interim Technical Memorandum in June 2017 and a draft report in November 2018.2
The Managing Risk in Rapid Renewal Projects program (R09) seeks to develop a simple, reliable, and credible way for States to conduct risk management. The product that resulted from the program was the Guide for Managing Risk on Rapid Renewal Projects.(42) The R09 product was developed through SHRP2 and provides practical tools and techniques for minimizing risk and exploiting opportunities on transportation projects.(42) The tools offered in the R09 product include risk-management checklists, materials for applying risk management, and the curriculum for a 2-day course that provides instruction on the risk management process. Together, these tools are intended to reduce project delays, cost overruns, and traffic disruptions that can arise from unmanaged project risks.
This evaluation seeks to understand how the R09 product and implementation support has changed risk management practices and affected project delivery in four lead-adopter states—Florida, Minnesota, Oregon, and Pennsylvania. The evaluation will focus on three key areas: dissemination, adoption, and project delivery. Dissemination will determine the level of exposure States have had to R09 concepts and processes. Adoption will assess the extent to which states have institutionalized the R09 process. Finally, project delivery will gauge how R09 has affected project cost and timeline projections.
This evaluation relies on two methods of data collection: document review and stakeholder discussions. The evaluation team is requesting documentation from the lead-adopter States that demonstrates the extent to which R09 concepts were introduced and distributed, how States are incorporating R09 concepts into standard practices, and the ways in which R09 concepts are being used on actual projects. Evaluators will conduct stakeholder interviews and attend peer-exchange events to supplement its review of documents.
The final evaluation plan was delivered in September 2016. The evaluation team conducted a gap analysis of the documentation already collected. Discussions with stakeholders responsible for developing the R09 product started in October 2016. In January 2017, the team attended a peer exchange with the lead-adopter States. At the peer exchange, evaluators held in-person discussions with State transportation department representatives. Data collection is expected to continue through the spring/summer of 2017. The draft final report will be delivered in December 2017.
Precast concrete pavement (PCP) is an innovative practice of using prefabricated concrete panels for pavement and roadway maintenance and rehabilitation. This practice is often used in high traffic–volume areas and in marginal weather because of the construction and overall travel-time savings that it provides. FHWA has led research efforts in this field since the mid-1990s and has continued to support the development of PCP through technical reports and implementation assistance under SHRP2.(38)
PCP evaluation seeks to better understand the outcomes of this developing technology. While existing research suggests that there are clear time savings and advantages of using PCP, these advantages have not been fully understood or quantified. In addition, while cost information is known, it is unknown to what extent the advantages of PCP exceed the costs, if at all, compared to existing alternatives. The evaluation also assesses the broader efficacy of FHWA’s research efforts.
This evaluation will use a benefit–cost analysis (BCA) framework to understand the impact of PCP installations. This will be done by comparing each PCP project against an estimated baseline or counterfactual. Because each project type varies, the baseline or counterfactual may vary as well. Once the benefits and costs of using PCP are compared to the individual alternatives, overarching themes and trends will be identified. In addition to the BCA, the evaluation will rely on interviews with State agencies who have conducted PCP projects. These interviews will generate qualitative information on attitudes related to PCP, facilitating quantitative data collection and understanding of the role played by FHWA in the development and adoption of PCP.
Finding: PCP has significant benefits over the high-early-strength concrete alternative.
While both PCP and high-early-strength concrete can be used during overnight closures for rapid repair projects, agencies feel that PCP provides more long-term benefits as it is more durable and requires less maintenance compared to high-early-strength concrete.
Finding: FHWA assistance, particularly workshops conducted, helped State transportation departments implement and adopt PCP.
State transportation departments implementing PCP under SHRP2 reported that assistance provided by FHWA and its contractors was significant and they relied upon it extensively. Particularly, State transportation departments reported that the workshops conducted were extremely helpful in providing the States with information needed to implement PCP.
The evaluation team has completed data collection for phase 1 and is currently preparing the Phase 1 Draft Report, which will be delivered in February 2017. Phase 2 will begin thereafter and will be completed in early 2018.
The Center for Innovative Finance Support (formerly the Office of Innovative Program Delivery), launched the Public-Private Partnership (P3) Toolkit in June 2013.(43) The P3 Toolkit is an educational resource containing analytical tools and guidance documents that assist policymakers and transportation professionals in implementing P3 projects. The toolkit forms the foundation of a broader P3 Capacity Building Program (P3 Program) that includes a curriculum of courses and webinars. The goal of the P3 Toolkit is to build State transportation department capacity for choosing P3s appropriately and executing them well.
The evaluation seeks to understand how the P3 Toolkit influences user decisions and actions regarding implementation of P3s. The team sought to evaluate how the P3 Program compared to other online resources and tools in developing P3s. The primary stakeholders that were considered by the team included FHWA Division Offices, State transportation departments, legislative analysts, and private consultants. The evaluation also attempts to uncover if the FHWA P3 Program has enhanced the state of the practice of P3s overall.
The evaluation will develop an initial understanding of the P3 Program by studying existing P3 Program usage data and outreach materials to understand how transportation practitioners are accessing and using program resources. This will be supplemented by interviews with P3 Toolkit users from FHWA Division Offices and State transportation departments to provide context for P3 resource usage. An online survey with FHWA Division Office staff will enhance what is learned in the interviews by measuring information needs, P3 Program resource usage, and program satisfaction.
This evaluation focuses only on resources developed from the launch of the P3 Toolkit through publication of the Draft Availability Payment Concessions P3 Model Contract Guide.(44)
An updated evaluation plan was submitted in June 2016. The evaluation team anticipates submitting a draft report in December 2016.
TIM is the “planned and coordinated multi-disciplinary process to detect, respond to, and clear traffic incidents so that traffic flow may be restored as safely and quickly as possible.”(45) The goal of TIM is to reduce the duration of traffic incidents and improve the safety of responders and those involved with incidents. National TIM Responder Training program contacts are available in each of the 50 States as well as in the District of Columbia and Puerto Rico. More than 5,200 TIM trainings have been conducted and 200,000 responders trained since 2012.(45)
The evaluation team will analyze the relationship between the TIM trainings and three TIM performance measures defined in FHWA’s TIM Performance Measures Focus States Initiative: roadway clearance time, incident clearance time, and the number of secondary crashes.(45) The evaluation seeks to determine the extent to which any change in the measures is attributable to the trainings.
The evaluation team worked with the TIM Program Office to identify States with strong TIM training programs, good data collection practices, and a willingness to participate in the evaluation. Arizona and Tennessee met these criteria. FHWA supplied the location and date of each TIM training along with the number of attendees by responder type (e.g., police, fire, emergency, towing, and State transportation department). Evaluators received 5 years of incident information from representatives of both States in the study. Together, these data sources are sufficient for applying statistical regression to isolate the impact of TIM-trained responders on TIM performance measures holding other factors (e.g., crash severity) constant. Semi-structured interviews with responders and managers will supplement the quantitative results.
The preliminary evaluation plan was delivered in July 2016. The evaluation team commenced a pilot study of the Phoenix metropolitan area in August 2016 and discussed preliminary results with FHWA and Arizona partners in September 2016. In September 2016, the evaluation team began its pilot study of Tennessee region 1 (Knoxville) and will discuss preliminary results with FHWA and Tennessee partners in October 2016. An updated version of the evaluation plan that takes into account recently encountered challenges and opportunities will be completed in February 2017. The final report will be delivered in June 2017.
FHWA Office of Policy has contracted the University of Nevada, Reno (UNR), to conduct research and analysis related to vehicle operating cost (VOC) estimation. The VOC model that is currently used in FHWA’s Highway Economic Requirements System (HERS) model is based on a 1982 study and requires updating because of technological developments since then.(46) UNR is in the process of updating the model and will also determine which groups beyond FHWA use the model. This work will continue through 2019.
The VOC evaluation seeks to understand the outcomes of UNR’s methodological update. The evaluation team will determine how the new VOC model is incorporated into HERS and other FHWA models and assess the awareness and use of VOC estimates and methods by other entities. The evaluation team will also gauge the impact of updating the VOC model and methods for the identified users.
The evaluation team will measure the outcomes of the update by examining case-by-case VOC-model use. Although some applications for the VOC model and methodologies are already known, most notably the HERS model, the team will determine other applications during the course of the evaluation. This evaluation is likely to be quantitative in nature and will analyze documentation, reports, and journal articles. Depending on usage levels, the team will conduct interviews with users to collect qualitative data related to perceptions of the updated equations and methods. Such qualitative data will supplement quantitative findings.
As UNR continues their work, the evaluation team will provide annual updates of the evaluation plan and begin full data collection activities in 2019. A final report is expected to be completed in mid-2020.
2 These technical memorandum were internal deliverables between FHWA and the evaluation team.
