Evaluation of Operational Impacts of Installation of Centerline and Edge Line Rumble Strips

Abstract

Research findings have shown that centerline rumble strips (CRSs) and shoulder rumble strips (SRSs) have significant safety benefits. SRSs have proved successful in reducing run-off-the-road crashes, and more recent research has shown that CRSs can potentially reduce head-on collisions. However, concerns about the operational effects of CRSs and SRSs remain. Specifically, how do the installations affect vehicle lateral position, passing operations, and shoulder usage? This paper documents the findings of research conducted for the Texas Department of Transportation on CRSs and edge line rumble strips (ERSs), a variation on SRSs that are placed directly on the marked edge line. Before-and-after analyses were conducted on Texas highways where CRSs or ERSs, or both, were installed. CRSs were evaluated with respect to passing operations and vehicle lateral position within the travel lanes; ERSs were evaluated for shoulder usage and vehicle lateral position during shoulder encroachments. The results of the study showed that CRSs generally improve vehicle lateral position by increasing the separation between opposing traffic streams on rural highways, although the results were mixed for curve sites. CRSs also have little effect on passing operations when they are installed in passing zones on rural two-lane two-way highways. ERSs were successful in reducing small, inadvertent encroachments onto the shoulder, whereas they had little impact on most normal shoulder usage.