How do you know when someone’s too high on marijuana to drive? There’s no simple answer. Measuring impairment from marijuana is scientifically difficult, but it’s increasingly important for public safety purposes. Nearly twice as many California drivers tested positive for drugs as for alcohol in a recent study, and 30 percent of drivers in the state’s fatal crashes now test positive for an impairing drug, according the San Diego Union-Tribune. If you are accused of marijuana-DUI in southern California, there are ways to defend against the charge, but you’ll need to contact an experienced Orange County DUI defense attorney immediately.

Six other states have adopted legal limits on tetrahydrocannabinol (THC) levels – THC is the active ingredient in marijuana – and 14 states have passed zero-tolerance laws. California’s lawmakers are still looking for a fair, objective approach. But even scientists disagree on how best to measure marijuana impairment. Studies show marijuana intoxication peaks about 13 minutes after smoking, and impairment remains high up to about 40 minutes after smoking. THC, however, can be detected in blood and urine days, even weeks after the user is no longer impaired. Frequent pot smokers will always have some level of THC in their blood, whether or not they are impaired.

Opponents of putting THC limits in the law, including UCLA public policy professor Mark Kleiman, say California’s existing law, which focuses on driver impairment, is the best way to keep intoxicated drivers off the streets. But prosecutors say a precise standard would make it easier for them to present cases to juries. If you’re accused of DUI anywhere in southern California, whether you were allegedly drinking alcohol or allegedly smoking pot, get the legal help you are very much going to need and take your case at once to an experienced Orange County DUI defense attorney.