The crash experience warrant in the Manual on Uniform Traffic Control Devices (MUTCD) specifies three criteria that must be met before a traffic signal can be considered for installation at an intersection. One of these criteria requires that five or more crashes of a type susceptible to correction by a signal must have occurred during a one-year period. Research was undertaken to evaluate the validity of this criterion and, if needed, to develop a crash experience warrant that is based on safety science and is consistent with the Highway Safety Manual (HSM). A procedure was developed for quantifying the safety effect of signal installation. It is based on the predictive methods in the HSM. The procedure considers the effect of signal installation on intersection crash frequency and crash severity. The procedure was used to develop revised content for the crash experience warrant. The minimum number of crashes was found to vary by area type, intersection legs, and number of lanes on each intersection approach. A revised crash experience warrant was prepared and recommended for inclusion in the MUTCD. The main products of the research are the proposed crash experience warrant contained in this report, a spreadsheet tool (http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_w204InSATTool.xls) that implements the safety evaluation procedure, and a safety evaluation guidebook (http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_w204InSATGuidebook.pdf) and spreadsheet user manual. (Author/publisher).
Samenvatting