Development of Crash Modification Factors for Bicycle Treatments at Intersections

DTFH6116D00039LThis research developed crash modification factors (CMFs) for bicycle treatments at urban intersections in the United States. The treatments evaluated were the presence of bicycle lanes, extension lines, through bicycle lanes, buffered bicycle lanes, and chevrons along the intersections. The research team compiled and analyzed safety data from Virginia and Texas. The evaluation considered the total number of vehicular crashes, including those crashes resulting in fatality and injury. Safety data collection focused on locations with available bicycle traffic data, or where direct demand models were applicable, and at intersections where bicycle intersection countermeasures were sufficient to conduct a statistical analysis. The research team included bicycle traffic volume counts as a key factor in the analysis, similar to how average annual daily traffic accounts for motor vehicle exposure. For the Virginia study sites, the research team developed estimates of average daily bicycle traffic using actual bicycle counts. For the Texas sites, the bicycle volume estimates were based on direct demand models developed by team members for this evaluation. The analysis found that having separated bicycle lanes and providing a mixing zone between bicyclists and motor vehicles at intersection approaches was associated with reductions in total, fatal and injury, and non-weather-related crashes in Texas. Other evaluations that considered bicycle and vehicular traffic volume, traffic control devices, and other geometric design features yielded CMFs that were not statistically significant. For the economic evaluations, benefit\u2013cost ratios for the two identified treatments were estimated as low as 5.9 when additional right of way was assumed, and up to 113.3 otherwise. Results indicate that these treatments are economically feasible