Increased traffic accident rates associated with shale gas drilling in Pennsylvania.

Objectives: We examined the association between shale gas drilling and motor vehicle accident rates in Pennsylvania.

Methods: Using publicly available data on all reported vehicle crashes in Pennsylvania, we compared accident rates in counties with and without shale gas drilling, in periods with and without intermittent drilling (using data from 2005 to 2012). Counties with drilling were matched to non-drilling counties with similar population and traffic in the pre-drilling period.