During which month is it riskiest to drive in the United States?

OBJECTIVES This study examined the variation in the U.S. road fatality rate per distance driven across the months of the year. METHOD The monthly fatality rates were analyzed for a 13-year period from 1994 through 2006. RESULTS The results indicate a systematic seasonal variation in the road fatality rate, with the highest rate in October and the lowest rate in March. CONCLUSION The obtained seasonal variation in the road fatality rate is likely a result of a joint influence of several factors that exhibit seasonal variations themselves (the duration of darkness, consumption of alcohol, proportion of older drivers, amount of leisure driving, and inclement weather).