Tomorrow is Tax Day, and if the yearly ritual of preparing your taxes isn’t enough to bring you down, truckers need to be alert to the fact that deadly highway accidents increase on Tax Day, according to a recent study.

The traffic death rate on Tax Day — which usually falls on April 15, but is on Tuesday, April 17 this year — was 6% higher than on other April days, according Dr. Donald Redelmeier, lead author of the study. That averages to about 13 extra deaths on each Tax Day, according to a report by WFMJ News, an NBC affiliate.

Researchers looked at 30 years of data from the National Highway Traffic Safety Administration and found 6,783 traffic-related deaths on Tax Day, or 226 per day, compared with 213 on other April days.

The study examined data from 1980 to 2009. The Canadian Institutes of Health Research helped pay for the study. A Canadian physician and researcher at the University of Toronto, Redelmeier, said he studied the United States because the American tax code is so complicated, and probably more stressful for taxpayers, than in other countries. The results appeared last week in the Journal of the American Medical Assn.

Having more motorists on the road and drivers taking routes that are not in their everyday routines might make Tax Day riskier, Russ Rader, a spokesman for the Insurance Institute for Highway Safety said. Other research, he pointed out, has suggested those factors, and sometimes alcohol use, may contribute to increases in traffic deaths on other days, including Super Bowl Sunday, July 4 and Election Day.