AAA Magazines

Driving and cannabis: A bad combination

Police lights at night in the city Photo by Daniel/

Driving after using cannabis, a.k.a. marijuana, is a dangerous practice, because the drug impairs judgment, motor coordination, and reaction time, according to the National Institute on Drug Abuse, the lead federal agency supporting scientific research on drug use and its consequences.

This is especially concerning because 11 states and Washington, D.C., have legalized the recreational the use of cannabis. Research by the AAA Foundation for Traffic Safety has shown that the number of fatal crashes involving drivers who tested positive for cannabis increased substantially after legalization.

The numbers

In Washington State, for example, nearly 9% of drivers involved in a fatal crash tested positive for THC, the drug’s main psychoactive ingredient, from 2008 through 2012, i.e., before the drug was legalized. That rate rose to 18% from 2013 through 2018, after recreational marijuana use became legal. Before legalization, on average 56 drivers tested THC-positive annually; that number increased to 130 drivers post-legalization.

What’s more, driving under the influence is far from an insignificant phenomenon: The survey revealed that an estimated 15 million drivers reported that in the previous 30 days, they’d gotten behind the wheel within an hour of using cannabis.

Police Car

Photo by Artem Konstantinov/

AAA’s stance on cannabis

AAA opposes the legalization of cannabis for recreational use because of its inherent traffic-safety risks and because it’s difficult to create legislation and enforcement that both protects the public and treats drivers fairly.

Seven states have set limits on the amount of THC a driver can have in their system, analogous to blood-alcohol levels. This might seem like a good idea, but it’s problematic because, at this time, no data reliably show what level of THC impairs driving, and THC testing often cannot be done until hours after a crash. Cannabis can also be detected in the bloodstream weeks after its ingestion.

AAA is committed to educating the public about the risks of substance-impaired driving. Through AAA Foundation research, AAA is working to improve our understanding of drugged driving and is working collaboratively with safety organizations to reduce the impact of substance-impaired crashes. AAA also supports increased training for law-enforcement officers to better detect and address drug-impaired driving.

Here are some safety tips from AAA regarding cannabis usage:

  • The impairing effects of cannabis usually occur in the first 4 hours after usage. If you use cannabis, don’t drive during that time period or afterward if you continue to feel any effects from the drug.
  • Never ride as a passenger in a car driven by someone who has been consuming cannabis.

If you host a party where cannabis is used, always remember:

  • Make sure your guests designate a sober driver in advance.
  • It’s illegal to offer cannabis to anyone under age 21.
  • Keep phone numbers handy for sober ride services.

Finally, remember that the first-offense costs of being convicted for driving under the influence of cannabis (or alcohol) can be more than $21,000 in fines, court costs, legal fees, and other penalties, and can also result in the loss of your driver’s license, your job, and possible jail time.

Even more important, you could cause injury or death to yourself or another person—the effects of which never go away.

Excerpted and adapted from the AAA Car Guide, also available in hard copy at AAA branches.

Automotive offers and deals


AAA Approved Auto Repair

Search approximately 7,000 AAA Approved facilities throughout the U.S. and Canada.

Learn more

AAA mobile battery service

AAA Mobile Battery Service

AAA provides a convenient testing and replacement service that comes to you.

Learn more

NAPA store exterior

Automotive discounts

Use your AAA membership to unlock do-it-yourself car-care discounts.

Learn more

AAA driving school

Teen driving resources

AAA cares about your teen’s safety and wants to help them develop safe driving habits.

Learn more

back to top icon