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United States Department of Transportation United States Department of Transportation

Keeping Drivers Safe with Innovative Intersection Design Research and Evaluation

Tuesday, May 11, 2021

According to recent data, more than 50 percent of fatal crashes and crashes resulting in injuries occur at or near intersections. 

Federal Highway Administration (FHWA) conducts intersection and interchange safety research to reduce crashes and keep drivers safe on the nation’s roadways. An early goal of this research was to develop innovative intersection and interchange designs to significantly improve the safety performance of intersections. FHWA initiated the Research and Technology (R&T) Evaluation Program in 2014 to assess the benefits of its R&T efforts and to ensure it was effectively communicating guidance to the transportation industry. 

In 2019, FHWA asked the U.S. Department of Transportation (U.S. DOT) Volpe National Transportation Systems Center (Volpe Center) to conduct an evaluation of Innovative Intersection Design (IID) research, which is part of a larger portfolio of evaluation work the Volpe Center has performed for FHWA. 

The IID evaluation report provides critical insight into FHWA’s decision-making processes, research activities, role within the broader infrastructure research community, efforts to promote deployment of innovative intersection and interchange designs, and the safety impacts of those efforts. The purpose of this evaluation is to assess the effects of FHWA’s investment in IID research, the availability and quality of such research, the adoption of IIDs in the U.S., and the impacts of intersections on safety and the operational performance of the U.S. transportation system.

More than 50% of fatal crashes and crashes resulting in injuries occur at or near intersections.

A U.S. DOT Volpe Center team evaluated the IID program using a range of qualitative and quantitative capabilities, including expert interviews, literature review, bibliographic data collection and analysis, infrastructure deployment tracking, benefit-cost analysis, and sensitivity analysis. 

The report highlights FHWA’s R&T efforts and the direct impacts of IID deployments on safety and the implementation of innovative intersection designs. The U.S. DOT Volpe Center provided recommendations to improve FHWA’s research efforts for safety and infrastructure programs as well as for R&T programs in general. The final report was delivered to the FHWA Office of Research, Development, and Technology in November 2019 and is currently under review. 

Key findings include the cumulative number of states that have implemented at least one of the innovative intersection and interchange designs recommended by FHWA. From 2007 to 2018, there was a dramatic increase in the number of states that deployed at least one innovative design, including continuous flow intersections, diverging diamond interchanges, mini-roundabouts, median U-turns, and restricted crossing U-turns. 

The report aligns closely with the U.S. DOT’s strategic goals of safety, infrastructure, and innovation. FHWA played a critical role in increasing adoption of IIDs across the country, particularly after the release of the Alternative Intersections/Interchanges: Information Report in 2010. 

To update findings in 2019, the U.S. DOT Volpe Center evaluation team conducted phone interviews with state transportation agency employees. Stakeholder interviews highlighted additional ways FHWA impacted implementation of IIDs by helping potential adopters overcome barriers. 

One interviewee put the impact of FHWA’s efforts this way: “I want to reinforce the value that FHWA, the Resource Center, some of the research material produced by FHWA… some of the one-on-one help, whether that’s the Resource Center or the local division office. Perhaps we could have gotten to where we are, but it would have taken several years longer, and I’m not sure that we would have gotten to where we are.” 

Celebrating more than 50 years of federal service to the nation, the U.S. DOT Volpe Center’s mission is to improve the nation's transportation system by anticipating emerging issues and advancing technical, operational, and institutional innovations for the public good.