Austin Smith of Miami University analyzed data from the U.S. Fatality Analysis Reporting System both before and after the 2007 daylight-saving rule change, and found that the spring-forward transition increased fatal crash risk by 5% to 6.5%, with four statistical tests suggesting that the increase is explained by sleep deprivation. Smith concludes, "Back-of-the-envelope calculations suggest that the spring transition into DST caused over 30 deaths annually at a social cost of $275 million." I assume this estimate is for just the U.S. Smith AC. Spring forward at your own risk: daylight saving time and fatal vehicle crashes. Am Econ J: Appl Econ. 2016;8(2):65-91. http://dx.doi.org/10.1257/app.20140100