Summertime and the Drivin’ is Easy? Daylight Saving Time and Vehicle Accidents

We investigate how exogenous variation in daylight caused by Daylight Saving Time affects road safety as measured by the count of vehicle crashes. We use administrative daily data from Greece covering the universe of all types of recorded vehicle accidents during the 2006-2016 period. Our regression discontinuity estimates support an ambient light mechanism that reduces the counts of serious vehicle accidents during the Spring transition and increases the count of minor ones during the Fall transition. The effects are driven from the hour intervals that are mostly affected from seasonal clock changes. We then discuss the potential cost implications of those seasonal transitions. In light of the talks about abolishing seasonal clock changes in the European Union (EU), our findings are policy relevant and can inform the public debate as empirical evidence for the block is scarce.