Marijuana & Driving

Dear Dr. Guterson: I know that drinking and driving is not a great idea. How about marijuana and driving? A: Obviously, with the increasing legalization and use of marijuana, this is a key question. Based on a research study that was published in 2022, the upshot was that using cannabis does indeed impair driving up to 3.5 to 4.5 hours after using. This may seem obvious to most, but what was significant is that it made no difference whether someone used alot vs. a little marijuana. In addition, the study found that one’s own perception of their readiness to drive safely was also off kilter. In other words, many in the study felt they were safe to drive 30 minutes to 1.5 hours after using - but they really weren’t. So - this is a case where self perception is not reality! Therefore, the general rule would be to throw your own feelings and thoughts out the window and wait 3.5 to 4.5 hours after using before driving.