Document Library

This report documents the results and technical performance analysis of the distributed testing pilot test 2 (Pilot 2) for the FHWA Virtual Open Innovation Collaborative Environment for Safety (VOICES) project. This pilot connected multiple test sites over a secure network and demonstrated how different models and simulation platforms can cosimulate together. This testing showcased how distributed testing can potentially improve the technical maturity of different applications and help ensure that algorithms and software from a variety of sources can work together safely to answer research questions important to the government, industry, and academia.

The American Association of State Highway and Transportation Officials (AASHTO) and the American Welding Society (AWS) provide extensive guidance documents that govern the welding of steel bridge members; however, none of the documents provide guidance regarding the number of times a welding nonconformance can be repaired without penalty or rejection, leading to uncertainty in the fabrication industry and potentially costly member rejections. While a few studies have investigated the effects of multiple weld repairs, none have studied the effects of multiple repair welds on members and practices common in the steel bridge industry. As such, there is currently insufficient data to determine whether multiple repair welds affect the material properties or the fatigue life of welded joints on bridge members. The goal of the current study is to investigate the effects of multiple repair welds on complete joint penetration (CJP) butt-splice welds and suggest an appropriate limit to GDOT and the steel bridge industry on the number of repair welds that can be performed at a single location. To accomplish this goal, the current study is comprised of three main research thrusts: (a) gather existing industry data and knowledge on welding nonconformances and repairs through a literature review and survey, (b) generate novel experimental data through a suite of material characterization tests on CJP joints with up to five weld repairs, and (c) generate novel experimental data through large-scale fatigue life tests on CJP butt-splice joints with up to five weld repairs. The results of this research show that up to five weld repairs can be performed at a joint without significant changes to the material properties or fatigue life of the CJP joint. The significance of these findings is that the data suggest: (a) there are no mechanistic or fatigue life indications that a CJP butt splice joint with up to five weld repairs will perform significantly differently than a CJP joint with no repairs, and (b) the repaired joint should still meet all applicable strength and fatigue design requirements.

Wrong-way crashes are rare but often severe events. This brief serves as an update to previous Foundation work examining these crashes from 2010 to 2018. Using FARS data, updated wrong-way crash numbers are provided, previously cited risk factors were examined in relation to the more recent crash data, and potential new risk factors were explored.

NCHRP Synthesis 659: Automated Traffic Signal Performance Measures: Management, Operation, and Maintenance examines how state departments of transportation are using high-resolution traffic signal controller data to monitor, manage, and improve signal performance. Automated Traffic Signal Performance Measures (ATSPMs) enable continuous, data-driven oversight of traffic operations and maintenance, supporting more proactive and efficient decision-making. While the benefits of ATSPMs are well documented, adoption across state DOTs varies due to challenges such as funding constraints, equipment and technology upgrades, staffing capacity, and organizational readiness. The synthesis highlights current practices, including the use of both controller-based and crowdsourced signal performance measures. It also explores implementation barriers, funding strategies, staffing considerations, and examples of how agencies integrate ATSPMs into day-to-day operational and maintenance workflows.

NCHRP Research Report 1149: Estimating Benefits of Closing Gaps in Active Transportation Networks: A Guide provides practical methods for evaluating the benefits of projects that improve connectivity in walking, bicycling, and rolling networks. Active transportation systems—including trails, sidewalks, bike lanes, and connected roadways—play a critical role in supporting safe, convenient travel for both recreation and everyday trips, yet many communities face fragmented networks with significant gaps. This guide offers accessible analytical approaches that can be applied across diverse geographies and project types, using publicly available datasets and research-based multipliers. Designed for broad usability, the methods rely primarily on national-level data sources to help agencies consistently estimate economic, safety, health, and mobility benefits.

NCHRP Web-Only Document 426, which accompanies the report, documents the development of the guide and summarizes the full research effort behind the recommended methodologies.

NCHRP Research Report 1164: The Business Case for Knowledge Management: A Guide provides state departments of transportation and other transportation agencies with practical tools to assess and measure the value of knowledge management (KM) initiatives. As experienced staff retire and collaboration across disciplines increases, agencies face growing challenges in preserving institutional knowledge and ensuring effective knowledge transfer. The guide outlines approaches for evaluating how KM practices contribute to improved business processes, workforce development, and organizational performance. It helps agencies articulate the return on investment of KM activities and integrate them into broader performance management strategies.

Accompanying the report, NCHRP Web-Only Document 437: Assessing and Measuring the Business Value of Knowledge Management documents the research effort and provides additional detail supporting the guide’s development.

Technological change has left many agencies managing numerous legacy systems and disparate architectures that, despite their limitations, remain valuable. To support cross-functional decision-making, some agencies are enhancing these systems by adopting data lake or data warehouse approaches. Advanced data representation and knowledge management techniques, such as developing a data ontology, could improve these strategies. A data ontology is a framework for characterizing and defining classes, attributes, and their relationships in a domain, providing a shared meaning across multiple users.

NCHRP Research Report 1169: Data Ontologies for Data-Driven Decision-Making: Development and Use, produced by TRB’s National Cooperative Highway Research Program, explores the implementation of a conceptual framework designed to help guide transportation agencies in the development and implementation of data ontologies. The report addresses the value of data ontologies from both business and technical perspectives and emphasizes the organizational, functional, and technical needs for successful integration of data ontologies.

Supplemental to the report is NCHRP Web-Only Document 441: Data Ontologies for Data-Driven Decision-Making: Research Approach and Findings.

Pedestrian safety has become an increasing concern in the United States, as significant rises in pedestrian fatalities and injuries have placed a spotlight on efforts to improve safety for people walking to school, to work, or for pleasure. State departments of transportation (DOTs) have implemented a range of pedestrian safety measures, but they continue to face numerous challenges.

NCHRP Synthesis 662: Pedestrian Safety Enhancements by State DOTs, produced by TRB’s National Cooperative Highway Research Program, examines how state DOTs are enhancing pedestrian safety through infrastructure upgrades; crossing and monitoring technologies; and the implementation of relevant policies, regulations, and legislation. The synthesis also highlights public education campaigns, community engagement strategies, speed management efforts, and Safe System approaches. In addition, it documents collaborations with partner agencies, methods used to evaluate safety outcomes, and challenges encountered in implementing pedestrian safety improvements.

The Highway Safety Improvement Program (HSIP) and the State Highway Safety Program are federal initiatives designed to improve highway safety and reduce fatal and serious injuries on the nation’s roadways. HSIPs are typically administered by state departments of transportation (DOTs) and may be structured differently across states. The State Highway Safety Program is managed by Highway Safety Offices (HSOs) in each state, which may be housed within the DOT or in another state agency.

NCHRP Synthesis 661: Coordination of Highway Safety Improvement Program and Highway Safety Office Activities, produced by TRB’s National Cooperative Highway Research Program, explores how states organize, manage, and align their HSIPs and HSOs. The report examines existing coordination of these functions through shared planning, data exchange, performance measures, and reporting processes. It also documents coordination practices related to funding, safety program implementation, public participation and engagement efforts, and the use of data tools and dashboards.

Before the 1960s, rural communities had little influence over transportation planning, despite substantial state and federal investment in rural infrastructure. Over time, federal policy emphasized greater rural participation, encouraging state departments of transportation (DOTs) to adopt planning approaches in nonmetropolitan areas that engaged communities and local officials. Early efforts focused on consultation with rural officials and the use of regional planning entities (RPEs) as intermediaries. Congress later authorized the designation of Regional Transportation Planning Organizations (RTPOs) for non-metropolitan planning. Although few RTPOs have been formally designated, many state DOTs work with RPEs or similar organizations that perform RTPO-like functions. These entities are now important partners in rural planning, though their roles and relationships with state DOTs vary across states.

NCHRP Synthesis 663: Transportation Planning in Non-Metropolitan/Rural Areas, produced by TRB’s National Cooperative Highway Research Program, highlights strategies employed by state DOTs to ensure effective coordination with non-metropolitan officials. The report covers governance and rural planning structures; roles and responsibilities; cooperation with local officials; capacity building; transit and multimodal planning; and key challenges and barriers. It also identifies observed practices that may support effective coordination and areas where additional research is needed.

State departments of transportation (DOTs) have effective procurement processes for highway construction but lag in acquiring new business technologies. As they invest in advanced solutions for communications, asset management, and human resources, they aim to leverage artificial intelligence and cloud-based big data tools. However, traditional procurement methods typically relied on by state DOTs focus on individual purchases rather than long-term goals and often fall short in addressing the growing complexity of these systems and evolving customer needs. This can create challenges in acquiring technological products and services.

NCHRP Research Report 1145: Practices for Transportation Agency Procurement and Management of Advanced Technologies, from TRB's National Cooperative Highway Research Program, presents a guide that includes successful strategies and practices for procuring new and innovative transportation system technologies.