Clear Rule

The rules around marijuana use can be confusing. But when it comes to marijuana use and driving, all you need to remember is one clear rule:

Driving impaired is illegal everywhere.

Driving impaired is illegal everywhere.

Everything else can get kind of hazy.

When you feel different, you drive different. Everything else can get kind of hazy. So, if you want to think through some of the things experts and leading researchers are learning about marijuana’s effect on your driving, you can do that here.
Index
Issue
2
Increased Crash Risk
Subject

"Driving under the influence of cannabis has been associated with 20-30% higher odds of a motor vehicle crash."

Why it matters?

The association between the level of THC (the psychoactive ingredient in marijuana) in the blood and either acute intoxication or driving impairment remains a subject of controversy.

That said, a 2016 review that summarized evidence from 21 studies in 13 countries, with a combined sample count of 239,739 participants, found that driving while under the influence of cannabis was associated with 20 to 30 percent higher odds of a motor vehicle crash.

Also, important to consider: driving under the influence of marijuana may not have been the culprit in all of these crashes. Many of the studies included drivers who reported recent or regular cannabis use, but were not technically intoxicated nor impaired while driving.

Clarity Level
Medium
Abstract
This study provides an in-depth review of the most recent evidence regarding the health effects of using cannabis and cannabis-derived products.
Abstract
This study provides an in-depth review of the most recent evidence regarding the health effects of using cannabis and cannabis-derived products.
This ranking indicates how “settled” we feel an issue is. Issues that are clear-cut, fully-researched, and conclusive have a “High” clarity level. Issues that are involved in ongoing research, or focus on matters that require additional study, have “Medium” or “Low” clarity levels — depending on the amount and strength of supporting research.