Do Traffic Tickets Reduce Motor Vehicle Accidents? - Working Paper

Traffic tickets are very unpopular among drivers, but to what extent do they affect behavior? do they reduce fatalities? These questions are addressed by Luca's paper "Do Traffic Tickets Reduce Motor Vehicle Accidents? Evidence from a Natural Experiment".

 
Abstract:     

"This paper analyzes the effect of traffic tickets on motor vehicle accidents. OLS estimates may be upward-biased because police officers tend to focus on areas and periods with heavy traffic and thus higher rates of accidents. This paper exploits the dramatic increase in tickets during the Click-it-or-Ticket campaign to identify the causal impact of tickets on accidents using data from Massachusetts. I find that tickets significantly reduce accidents and non-fatal injuries. However, there is limited evidence that tickets lead to fewer fatalities. I provide suggestive evidence that tickets have a larger impact at night and on female drivers."

 

The deterrence effect of law enforcement is a much debated issue, and traffic tickets are even more controversial on their own as they are/could be used as revenue source. Nevertheless, the stated purpose of the fines is to enforce traffic regulation and, if we are to believe the ad campaigns, prevent fatalities. Using a seat-belt law and enforcement campaign is a nice natural experiment, as seat-belt are designed for preservation of life.

The study shows that tickets do lead to a reduce number of accidents but not necessarily to a decrease in fatalities. This may be due to the allocation of police resources, that may be placed in locations and times that may not prevent fatal accidents (i.e. nearly 50% of fatalities occur at night).