Only days away from 4/20, a day of celebration for marijuana users, new survey results from the AAA Foundation for Traffic Safety found some of those who partake make the risky decision to get behind the wheel of a car — before they should.

The survey found 53% of those surveyed admitted consuming cannabis an hour or less before driving.

“Quite often, people think that it doesn’t significantly affect them and their driving performance,” said Tom Marcotte, co-director of the Center for Medicinal Cannabis Research at the University of California San Diego.

Marcotte was among the experts AAA worked with on the survey.

Marcotte said in another study he conducted, participants were instructed to smoke marijuana and use a driving simulator when they felt they were ready to drive. He said early on after getting high, half of those who participated said no to driving; but by 90 minutes, many thought they were ready to get into the driver’s seat even though they simulator showed they were not ready.

“We think that’s a particularly risky time where people feel it’s wearing off, but it’s not,” Marcotte said.

He said while some people can develop more of a tolerance to the active ingredient THC, they may smoke more to get high and are just as impaired as less frequent users that do the same.

“People are not always the best judge of whether or not they’re impaired. Even if they have the best of intentions, they could be incorrect in their assessment,” Marcotte said.

The AAA survey found that 47% of people believe they drive the same, 15% think they drive a little better, whereas 19% believe consuming cannabis before driving makes them a much better driver. Marcotte cautions against that belief.

“Some people may feel they’re a better driver because they’re more focused, but actually focused attention is not perhaps what’s most important as being able to see what’s happening in your periphery,” he said.

Also, unlike alcohol use, most drivers using marijuana don’t take more risks on the road, but knowing they’re prepared, may make them drive more slowly.

“That doesn’t necessarily mean they’re a better driver, but it is a different type of risk than what happens when people get intoxicated by alcohol,” Marcotte said.

His studies have shown it can take many people anywhere from 3.5 hours to 4 hours for the effects to subside, though he cautions marijuana-infused food can increase that time.

AAA said marijuana use can impact users differently, but sleepiness, brain fog, changes in visual or auditory perception, impaired body movement and hallucinations are among the reported side effects.

In one of its surveys, AAA found getting the message out about the dangers of driving impaired could be helped by the cannabis industry, as almost 39% of users said they’d trust messaging about marijuana from cannabis industry groups and cannabis brands and companies.

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