The only guaranteed way to stay safe is by not driving after using marijuana.

With the passage of State Question 788, Oklahomans have elected to allow marijuana to be used for medicinal treatment. As other states have begun to loosen their legal restrictions on marijuana, the country has experienced negative consequences for roadway safety.

For example, according to NHTSA, there was a 48% increase in weekend, night-time drivers testing positive for THC from 2007 to 2013-2014. As these numbers continue to climb, Oklahomans are faced with confronting potential threats to our roadways. The only guaranteed way to stay safe and avoid the lethal implications of drugged driving is by simply never driving after using marijuana.

Although some of the rules and regulations for consuming marijuana have changed, the rules of the road remain the same. Medical license or no medical license, if you get behind the wheel with any trace of THC in your blood, saliva, urine or any other bodily fluid, you will be arrested and charged to the fullest extent of the law.

Marijuana Misconceptions

There are many misconceptions about the effects of marijuana on driving performance. But multiple national studies demonstrate its negative effects.


In many of these reports, subjects who consumed marijuana experienced slower reaction times paired with increased heart rate and brain activity. These side effects can adversely influence driving capabilities, endangering both users and other drivers.

Mixed Reactions

Depending on whether you smoke, vape or ingest edible marijuana, each method of consumption can cause different side effects. Ingestion methods also affect how much time it takes for users to feel the psychoactive effects of marijuana.

Smoking or Vaping

  • 10 – 30 Minutes: Approximate time after the last puff until peak effects occur.
  • 2 – 5 Hours: How long a driver is impaired after taking marijuana.


  • 30 Minutes – 2 Hours: Approximate time after last dose when someone begins to feel the psychoactive effects.
  • 4 – 12 Hours: Depending on the dose, your metabolism and other factors, this is how long a driver is impaired after consuming edible marijuana.

Marijuana’s Effects on Driving

Much like alcohol, marijuana can affect a driver’s peripheral vision, lane-maneuverability and overall decision-making. It can also have the following effects:

  • Slower reaction time
  • Difficulty maintaining attention
  • Reduced peripheral/side vision
  • Difficulty staying in traffic lane
  • Impaired distance perception
  • Slower decision-making
  • Reduced coordination