Development of Crash Modification Factors for Left Side Rumble Strips

摘要

This study evaluated the feasibility of adding rumble strips to the left side of rural divided highways in New Brunswick. A 6-year retrospective review of 406 crashes that occurred on Route 2 and Route 95 from 2004-2009 was supplemented with an in-depth analysis of 289 incidents that occurred on the Brun-Way owned and operated sections of Route 2 and Route 95 during the years 2006–2011. The report revealed that despite significantly more traffic travelling in the right (outside) lane, a larger amount of run-off-the-road (ROR) crashes occurred to the left (non-rumble strip) side. The potential benefit of left rumble strip installation was developed by comparing the safety performance of highway sections with right-side-only rumble strip installation versus known Crash Modification Factors (CMFs) developed from highways with rumble strips on both sides. A CMF that estimates the incremental benefit of installing a left side rumble strip in addition to an existing right side rumble strip was estimated to be 0.93 for all ROR crashes. In other words, installing a left side rumble strip (where a right one exists) would yield 7% fewer ROR crashes. A conservative benefit-cost analysis revealed that the B/C ratio of the installation of left side rumble strips in New Brunswick ranged from approximately 14 to 20 depending on the source dataset.