This article describes a study that was conducted to help identify high-risk areas at the county level in Arizona for three major driver behaviour issues: alcohol-related crashes, speeding-related crashes, and unbelted occupant-related crashes. The goal is to identify priority areas where limited resources can be spent toward driver behaviour-related safety treatments that will maximize safety benefits. Traffic crash and exposure data were collected for a five-year study period (2002-2006). Data queries were performed to find the frequency of various types of crashes and injuries for all counties in the state. Crash rates were calculated using three exposure variables based on severity of crash for each of the focus areas. A safety performance index developed by the authors in previous research was used to calculate the relative performance of various counties for each of these special focus crash categories. The safety performance index is a disutility function and is considered a surrogate measure of risk. The findings from the study suggest that the application of the safety performance index in area wide safety improvement projects can benefit funding agencies in their identification and resource allocation process.
Abstract