This study examined the effect of traffic tickets on motor vehicle accidents.
Ordinary least squares (OLS) estimates may be upward biased because police officers tend to focus on areas where and periods when there is heavy traffic and thus higher rates of accidents. The current study examined the dramatic increase in traffic tickets issued during the Click‐it‐or‐Ticket campaign to identify the causal impact of tickets on accidents, using data from Massachusetts. The analysis found that issuing traffic tickets significantly reduced accidents and nonfatal injuries. The evidence also suggests that tickets had a larger impact at night and on female drivers. (publisher abstract modified)