Think you drive better when you’re stoned - you’re kidding yourself!

With the legalization of marijuana in Canada many people are wondering about the effects marijuana has on driving.

How much is too much? Should there be a legal limit like with alcohol? How does it affect driving?

These aren’t new questions. They have been asked by researchers, health professionals, law enforcement and users themselves for many years. But with legalization more attention has been made to these questions. And with that, the realization that we don’t have all the answers.

So what do we know?

Though more research is needed to answer some questions there are some things we know:

Marijuana does have an effect on your ability to drive safely. It can:

  • Slow your reaction time
  • Make it hard for you to concentrate and make decisions
  • Affect your ability to steer correctly and stay in the driving lane
  • Affect your hand-eye coordination
  • Make managing your speed more difficult

All these are important functions for driver safety.

Is there a level of marijuana where driving is not affected?

This is a question we don’t have a clear answer on. It’s the Tetrahydrocannabinol or THC level that impacts driving. This is the ingredient that causes the ‘high’. And because it affects the way our brain functions, it has an effect on driving. And the amount of THC varies depending on the product, strain and how you use it. So for now, until more quality research can be done, when it comes to driving there is no ‘safe’ level of THC.

How long does it affect my driving?

Everyone metabolizes marijuana at a different rate. But most people shouldn’t drive within 5 to 6 hours after smoking recreational marijuana…. even longer after ingesting it. To be safe, plan your ride home just like you would when drinking alcohol.

And don’t think because you don’t feel the ‘stone’ anymore you are safe to drive. It’s impact on driving can still be there even if you don’t feel the effects.

What about medical marijuana?

The impact medical marijuana has on driving depends on the level of THC. Cannabidiol or CBD is the therapeutic ingredient of marijuana. Medical marijuana has both ingredients, but at different levels depending on your needs. If you are using medical marijuana, talk to your health professional about the level of THC in your product and if could affect your driving.

The bottom line is, if you are using recreational marijuana, don’t drive.


December 19, 2018 by Alex Thompson

I never really thought about using marijuana and driving. Of course it makes sense that it would affect driving. Hopefully we get some valuable research that will better inform us of its use and driving. And now with it legal in Canada, I hope other drivers respect it's affect and refrain from driving when they use it! We are only as safe as the other drivers on the road!!

December 19, 2018 by Simon Harvey

We really need some public announcements about this. Theres information about it's bad effects on growing brains...but I haven't seen anything warning about driving. We need to spread the word!