Examining the impact of centerline rumble strips on reducing rural two-lane head-on collisions in Maine

Abstract

Among all traffic collisions, lane departure crashes are the leading type of serious traffic crashes in Maine, comprising 73% of statewide traffic fatalities. To reduce these crashes, the Maine Department of Transportation (MaineDOT) installed shoulder and centerline rumble strips on roadways to prevent lane departure crashes. Specifically, 511 miles of centerline rumble strips were installed on undivided bidirectional rural two-lane roadways to prevent head-on collisions. Given the severity of head-on collisions, coupled with significant investment in rumble strip installation, there is a need to understand the impact of rumble strips in reducing lane departure crashes. This study uses observational before-and-after studies with two methods: comparison group, and empirical Bayes (EB) comparison group to explore the effectiveness of centerline rumble strips in reducing head-on and opposite sideswipe crashes on rural two-lane roadways and compute crash modification factors (CMFs) in Maine. The evaluation investigated the impact of centerline rumble strips on reducing both the total as well as fatal and injury head-on and sideswipe collisions on rural two-lane roadways. The economic benefits of using rumble strips are also explored using a benefit-cost ratio analysis. This study finds that the installation of centerline rumble strips is associated with reductions of 28%-48% of head-on and opposite sideswipe collisions on rural two-lane roads. In addition, the benefits of the rumble strip installations are at least 14 times the cost. The centerline rumble strips are cost-effective countermeasures to reduce head-on collisions on rural two-lane roadways in Maine.