Cannabis & Driving

How does marijuana affect driving?

What we know: Cannabis can cause drowsiness and worsen the functions that are critical to safe driving. The dangers include slower reaction time, altered perception of speed and distance, and reduced coordination. All can increase the risk of a collision.

What we’re watching: Reliable roadside tests for detection of marijuana use are still under development. While some tests can identify the presence of cannabis, the results alone cannot yet prove the level of impairment.

Can you be arrested for driving under the influence of cannabis?

What we know: Driving under the influence of medicinal or recreational marijuana – or anything that impairs your ability to drive – is a crime. A first offense can lead to possible jail time, loss of driver’s license, and a criminal record. Fines, court costs, auto insurance increases, and legal fees can total up to $21,000.

What we are watching: Despite the risks and criminal penalties, the number of people driving high continues to increase. Nationwide, in 2015, one in five drivers who died in crashes had used marijuana, often in combination with alcohol or other drugs. Educational efforts to prevent marijuana-impaired driving by youth and adults are being developed. The goal is to decrease crashes and save lives.

Is it okay to use medical marijuana when driving?

What we know: In California, it is unsafe and illegal to drive under the influence of any substance that causes mental or physical impairment, including marijuana. Medical marijuana users are not exempt from this law and may not drive under the influence or while using cannabis. It is also against the law to drive a vehicle with marijuana not in a sealed container.

What we’re watching: As medical and recreational marijuana access and use increase across the country, research about the possible benefits must be balanced with a focus on public safety for individuals and communities.