Death and taxes may be more closely related than you think.

A new study links the income tax deadline day to a rise in fatal motor vehicle crashes.

So on tax day -- this year, April 17 -- make sure you buckle up, don't speed, and don't drive if you're tired, distracted, or have been drinking, the researchers write in the Journal of the American Medical Association.

On average, there are 13 more fatal road crashes on tax day, compared with other days around the same time of year.

Exactly why that is isn't clear. "One explanation is that stressful deadlines distract drivers and contribute to human error," the researchers write.

Other possible reasons include alcohol use, altered driving patterns, and sleep deprivation, report the researchers, who included Donald Redelmeier, MD, of the University of Toronto.

Death and Taxes

Redelmeier's team analyzed information from the IRS and National Highway Traffic Safety Administration from 1980-2009. They compared the number of fatal motor vehicle crashes that occurred on tax day vs. the day one week before and after.

The results showed 404 more people died in road crashes on tax days during the study period compared with non-tax days. That works out to an average of about 13 more deaths involving motor vehicle accidents per year on tax day.

The increase in fatal crash risk may be small, but the researchers say it's similar in magnitude to the increase in fatal road crashes found on Super Bowl Sunday.

SOURCES:Redelmeier, D. Journal of the American Medical Association, April 11, 2012.News release, American Medical Association.