How Long Should Marijuana Users Wait Before Driving? It's an Open Question in Pot-Legal Colorado and Washington, Reports

How Long Should Marijuana Users Wait Before Driving? It's an Open Question in Pot-Legal Colorado and Washington, Reports

SANTA MONICA, Calif. — January 17, 2013 — When Washington and Colorado voted to legalize recreational marijuana use in November, both states' lawmakers were forced to consider whether to update their DUI laws. But according to, the premier resource for car shopping and automotive information, the solutions aren't exactly cut and dried.

"Marijuana and alcohol affect users very differently, so it doesn't always make sense to simply lump a marijuana DUI with an alcohol DUI," says Features Editor Carroll Lachnit. "Everyone knows that driving under the influence of marijuana is dangerous, but there's never been a national standard in place to identify someone who's 'legally stoned' the way we can identify someone who's 'legally drunk.'"

The state of Washington made the first attempt to set that standard with a new law that makes it illegal to operate a motor vehicle with a blood level of 5 nanograms per milliliter of THC — the active ingredient in marijuana — as detected by a blood draw. If a driver exceeds this threshold, he or she will face the same conviction as a driver under the influence of alcohol or other drugs. Colorado is considering a similar law, but as currently proposed it would give latitude for those over the limit to argue that they were not impaired.

According to advocates of marijuana law reform, detected levels of THC in someone's system does not necessarily have a direct relationship to impairment. As a result, there's a debate over how long someone should wait to drive after smoking marijuana. The National Highway Traffic Safety Administration (NHTSA) says that marijuana can impair driving performance for up to three hours after use. But even marijuana advocates admit that number may be too conservative. spoke with one attorney in Washington who counsels medical marijuana users to wait at least 10 hours. Another attorney in Colorado says that any marijuana user should get a good night's sleep before getting behind the wheel. has more details on what marijuana users — especially those in Washington and Colorado — should know before they decide to get behind the wheel at

About, Inc.
At, we're committed to helping people find the car that meets their every need. Almost 18 million visitors use our research, shopping and buying tools every month to make an easy and informed decision on their next new or used car. Whether you're at the dealership or on the go, we're always by your side with our five-star iPhone and iPad apps and our Android App. Our comprehensive car reviews, shopping tips, photos, videos and feature stories offer a friendly and authentic approach to the automotive world. We're based in Santa Monica, Calif., but you can connect with us from anywhere by following @Edmunds on Twitter or by becoming a fan of on Facebook.

Leave a Comment

Edmunds Universe

Follow Us:

Edmunds Price Promise® TV Spot

Company Profile and HistoryCompany Profile and History


Corporate Communications

Jeannine Fallon/Stephanie Mar/Aaron Lewis

Media Hotline (media inquiries only)

pr (at) edmunds dot com