Alcohol consumption measured at roadside surveys and variations in traffic injury crashes

This analysis examines whether roadside surveys that measure changes in the prevalence of driving after drinking can be used to evaluate the impact of interventions designed to reduce alcohol-related traffic crashes. Using data collected at a roadside survey over a 4-year period in two California communities, this analysis examines the relationship of BAC and drinks since 5 p.m., aggregated on a monthly basis, with nighttime injury crash data from the California Highway Patrol aggregated on a monthly basis. A regression analysis was used in which daytime injury and drinking style were covariates. The data demonstrate that temporal changes in drinking and driving collected at a roadside survey reflect temporal changes in nighttime injury rates. Hence, this study substantiates the use of roadside surveys as an appropriate methodology to evaluate drinking and driving interventions.