Recently I had an individual come and see me about a possible Marijuana DUI charge. Hypothetically if an individual admitted to use, which is legal in the State of Washington, but was adamant they were not impaired by their "one" puff prior to driving and that the use was for therapeutic reasons can they still be convicted?. Typcially I would assure an individual that one puff wouldn't get them close to the per se limit of 5 ng/mL of whole blood. But it does beg the question, how many puffs are too much given the 5 ng/mL standard?
When the legislature enacted the per se limit of 5 ng/mL of whole blood as a per se "impaired" limit it essentially relied upon other state's per se limits. There is no definitive research out there which establishes that ever person who had a whole blood concentration of 5 ng/mL is impaired to the degree that they cannot operate a motor vehicle.
So when someone is a regular user, much like a regular consumer of alcohol, how does that individual know how much is too much? There is simply no way to tell given the quality of the herb, the potency of the particular varietal they smoked or consumed. It is a very slippery slope that people are not encountering. When in doubt, don't smoke and drive but if you are therapeutic user for example you would be well-advised to have your blood checked a few times after you normal use to determine where you are on the spectrum of ng/mL measurements.
Personally I believe it isn't fair for the therapeutic users to be subjected to arrest simply because some overzealous trooper or officer smells marijuana and automatically thinks they have someone impaired when they typically have very limited ability to determine impairment using roadside test which were implemented to gauge impairment of drivers who consumed alcohol. This area is ripe for litigation given law enforcements limited ability to tell if someone is impaired or under the influence of marijuana.
Just look at NHTSA's own description of use of marijuana, it is so vague I wonder if the Washington State Legislature really did any research at all. Also, see this resource which says that marijuana use doesn't significantly impact driving abilities as well as a University of Washington study which says it still needs more research to definitively say whether there is any impact on driving.
If you or someone you know has been arrested for a DUI, including a Marijuana DUI, call today to speak with a highly experienced DUI attorney, Seattle Marijuana DUI Lawyer, Nate Webb at (425) 398-4323.