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Development of a Systemic Safety Improvement Plan for Two-Lane Rural Roads in Virginia
Hyun W. Cho, Ph.D., Benjamin H. Cottrell Jr., P.E., and In-Kyu Lim, Ph.D., P.E.
Hyun Woong Cho
Hyun Woong Cho
Benjamin H. Cottrell, Jr.
Benjamin H. Cottrell, Jr.
Year: 2019
VTRC No.: 21-R10

About 17,500 crashes per year occur on the more than 32,800 lane-miles of undivided two-lane rural roads maintained by the Virginia Department of Transportation (VDOT), and crash numbers are increasing.  Roadway departure (RD) crashes comprise about58% of crashes on these roads.  Since these crashes are widely distributed across the state, determining how and where to focus limited highway safety resources through the deployment of low-cost, high-benefit systemic countermeasures is paramount to beginning to reduce the number of crashes on these roads. 

The purpose of this study was to develop a systemic safety improvement plan for RD crashes on two-lane rural roads using low-cost countermeasures.  Segments that have the potential for safety improvement were selected using VDOT’s RD safety performance functions.  Decision tree analysis was applied to perform a systemic classification of roadway characteristics that are correlated with RD problems.  A list of countermeasures to deploy to target specific segments and patterns was developed based on the literature and input from VDOT staff. The countermeasures were intended to warn of curves ahead, delineate curves, and warn of lane/road departure. Before deployment, a study of the section by VDOT district traffic engineering staff is planned in order to finalize the safety improvement plan.  The output of the study will be a safety improvement plan to deploy treatments systemically to two-lane rural roads as part of VDOT’s safety program.