High drivers on 4/20 similar to DUI on Super Sunday

Here’s a pro tip from a couple of doctors: Be sure to make special plans on April 20.

That date, of course, is the unofficial holiday devoted to celebrating all things marijuana. (You might know it better as “4/20.”)

The two physicians — John Staples of the University of British Columbia and Donald Redelmeier of the University of Toronto — aren’t asking that you honor marijuana’s medicinal properties by experiencing them directly. Rather, they’re warning you to be on alert for others who do then get behind the wheel while they’re still under the influence.

Data from the U.S. National Highway Traffic Safety Administration show that the risk of a fatal vehicle crash on American roads is 12 percent higher after 4:20 p.m. on an April 20 than on similar days that have no particular connection to pot, Staples and Redelmeier found.

That may not sound like much, but it’s “comparable in magnitude” to the increased risk seen on Super Bowl Sundays, when football fans gather to watch the game over beers, wine and cocktails — then drive home, the pair wrote Monday in the journal JAMA Internal Medicine.

Staples and Redelmeier gathered 25 years of data collected in NHTSA’s Fatality Analysis Reporting System. They started with the year 1992 (the first full year after the magazine High Times turned 4/20 into a cultural phenomenon, the doctors said) and ended with 2016 (the most recent year with available data).

For all of the April 20s combined, there were 1,369 drivers involved in fatal motor vehicle crashes that occurred between 4:20 p.m., when the festivities generally get underway, and 11:59 p.m. (A crash was considered fatal if one or more people died within 30 days of the collision.)

That worked out to 7.1 crashes per hour. The doctors compared those figures with the days one week before and one week after April 20, when marijuana use was presumably more typical but all other conditions were roughly the same. During the identical 7-hour-and-40-minute period on April 13s and April 27s, there were 2,453 drivers involved in fatal crashes.

That worked out to 6.4 fatal crashes per hour.

The difference was too large to be the result of chance, the researchers found.

All of these extra deaths occurred even though “the vast majority of Americans do not celebrate 4/20,” Staples and Redelmeier wrote. If its popularity continues to increase, so too may the number of traffic fatalities.

Legislators and voters should keep this in mind as they consider new laws that would make marijuana more freely available 365 days a year, Staples and Redelmeier warned. At the very least, the pair wrote, policymakers should consider “strategies to curtail drugged driving.”