This RCUT is at the intersection of U.S. Highway 98 and Old Highway 63 North near Lucedale in George County. The intersection is designed to keep traffic flowing while reducing the number of crashes. Submitted photo
Amir Molan evaluating safety performance, updating designs of restricted crossings
A University of Mississippi civil engineering professor is studying the safety and efficiency of U-turns through two different research projects in hopes of improving traffic safety.
The Mississippi Department of Transportation has awarded $239,900 to Amir Mehrara Molan for a study of restricted crossing U-turns, also known as RCUTs. Additionally, the North Carolina Department of Transportation awarded Molan and his research partners a two-year, $208,555 grant to study the access points at either end of a U-turn crossover.
RCUTs are a traffic design that aims to reduce crashes by limiting left turns. Side streets are limited to right turns only; motorists wanting to go left can make a U-turn farther down the main road. MDOT has opened seven of the intersections in Mississippi since 2012.
The intersections are one of Federal Highway Administration‘s proven safety countermeasures. In fact, the implementation of innovative intersection designs such as RCUTs has been listed as one of the safe system elements in the FHWA’s Safe System Approach.
“RCUT intersections can reduce the number of fatal and injury crashes at an intersection as well as the injury severity of all crashes,” Molan said. “I am pleased to share that more than a dozen RCUT intersections have been implemented in Mississippi since 2012, with many more in the construction and planning phases.”
The MDOT project has two objectives, Molan said. The first is to conduct before-after safety evaluations that will accurately measure how much RCUTs have improved traffic safety. The second is to update the state’s design best practices for RCUTs, which were initially developed in 2010.
To achieve these goals, Molan and his research team will review past studies, use advanced safety models to analyze historical crash data and conduct focus groups with several state DOT experts. The results could help MDOT in future intersection improvement projects and the implementation of new RCUTs.
For the study in North Carolina, Molan is working with Taha Saleem, a research associate at the University of North Carolina Highway Safety Research Center. A similar study has been conducted by the U.S. Department of Transportation.
“Past studies from other states – mostly from North Carolina – showed significant safety improvements by replacing old intersections with RCUTs,” Molan said. “We are evaluating the safety performance of RCUTs when there are access points – side streets – near U-turn crossovers, compared to RCUTs with no access points.”
The researchers chose RCUTs for study because past studies have indicated they offer improved safety, Molan said. Based on crash statistics, about 45% of all fatal crashes occur in rural areas while only 19% of Americans live in those areas.
“Rural high-speed intersections include a significant percentage of those fatalities,” he said. “Therefore, safer intersection designs, such as RCUT, could significantly improve safety in Mississippi.”
Ole Miss graduate students Gaurav Aryal, of Nepal, and Troy Hill, of Tallahatchie County, have chosen RCUTs as the topic for their master’s theses. Aryal is focusing on the safety aspects of RCUT intersections, and Hill is working on design considerations. A doctoral student, Stephen Osafo-Gyamfi, of Ghana, is also assisting the research team.
These research projects provide ample learning opportunities for graduate students that will benefit them throughout their life, said Srinivas Pulugurtha, chair and professor of civil engineering.
“They range from understanding the role of unconventional designs and their implications on traffic operational performance and safety to challenges associated with data to assess the designs and application of advanced analytical methods,” he said.
“Overall, the experience working on the research projects and their interactions with experts and practitioners in the field will hone their problem-solving interdisciplinary skillsets and ability to make informed decisions.”
By Edwin Smith
