Oklahoma Highway Patrol Troopers say there is a big misconception among people who have medical marijuana cards and just how much marijuana someone can have before getting behind the wheel.

At DUI checkpoints across the state, law enforcement looks for not only drunk drivers, but also motorist under the influence of drugs. Even under the state’s medical marijuana law, it is still illegal to drive under the influence of any amount of marijuana.

“If we do an evaluation on you and you are under the influence of marijuana, you still will be arrested. It’s exactly like a DUI,” OHP Captain Donald Kerr said.

However, unlike alcohol, which has a blood alcohol content allowance under .08%, there is no allowable amount for marijuana, even for people with medical cards.

“We do the standardized field sobriety test, number one. And if you fail, you’ll be asked to do a state’s test, which most of the time will be a blood test,” Kerr said.

The results of the blood test are either positive or negative for marijuana.

According to the Oklahoma Highway Safety Office, a driver can be impaired for around 5 hours after using marijuana, with the drug affecting reaction time, maintaining attention and judging distance.

In 2018, 217 people died from drug related crashes, up from 199 in 2017 and 134 in 2016.

“It’s an impairment. Your cognitive skills aren’t the same,” Kerr said. “People need to realize that.”