Crash Impact of Smooth Lane Narrowing with Rumble Strips at Two-Lane RuralStop-Controlled Intersections

According to the Fatality Analysis Reporting System, the proportion of fatal crashes at unsignalized rural intersections constitutes approximately 37 percent of all fatal crashes at intersections nationwide. About 90 percent of these rural unsignalized intersection crashes occur on two-lane roads. As a low-cost remedy to address crashes at unsignalized intersections on two-lane rural roads, the Federal Highway Administration (FHWA) developed and evaluated a treatment to reduce approach speeds by narrowing lanes using rumble strips in the median and on the right-lane edge. This narrowing was applied for about 150 ft on the major road approach of two-way stop-controlled (TWSC) intersections on high-speed rural roads. Eight experimental sites were retrofitted between 2007 and 2008 in Missouri, Kentucky, Pennsylvania, Florida, and Maryland. Following the acquisition of at least 2 years of post-implementation crash data, pre- and post-implementation crash analysis was conducted to compare the performance of the new treatments. Results showed a 32 percent reduction in total crashes and a 34 percent reduction in fatal/injury crashes.