There are more deadly car crashes on unofficial weed holiday 4/20 than usual in the US

Researchers found there were more fatal car collisions on the unofficial holiday celebrating marijuana use.

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The weed-smoking celebration coincides with more deadly car crashes in the US (Elaine Thompson/AP)

Scientists have found that there are more deadly road collisions than normal on April 20, the unofficial celebration for marijuana consumers in the US known as 4/20.

Researchers from the Universities of Toronto and British Columbia found that on average there were 7.1 fatal car crashes per hour after 4:20pm on April 20, compared to 6.4 during control periods.

They looked at 25 years of data – between 1992 and 2016 – to see how many vehicle crashes there were in the US where at least one person involved had died within a month of the accident.

They found there was a 12% increase in the relative risk of having a fatal collision after 4:20pm that day, with an even higher risk for younger drivers.

A man smokes a marijuana joint (Kirsty Wigglesworth/PA)
A man smokes a marijuana joint (Kirsty Wigglesworth/PA)

In areas where marijuana use is legal, we know sales of the drug increase on that day. And driving under the influence of marijuana does increase risk of involvement in a traffic accident.

Car accidents in general do increase around holidays like Christmas – in part thanks to drinking, tiredness and more people on the roads.

In a 2003 study, researchers looking at 27 years’ worth of accident data on the day of the Super Bowl found a 41% increase in fatalities after the TV broadcast of the game had finished.

The study on fatal crashes on 4/20 was published in the journal JAMA Internal Medicine and can be read here.