In November 2012, Washington voters legalized recreational marijuana use by passing “Initiative Measure No. 502” (more commonly known as “I-502”). I-502 not only decriminalized use and possession of small amounts of marijuana, it made changes to Washington DUI (driving under the influence) law.
Prior to the passage of I-502, a Washington motorist could be convicted of a DUI for driving while:
So, a driver could be convicted of a DUI for marijuana use only if the prosecution could prove the driver was “affected by” the use. Showing the driver’s blood had a high concentration of marijuana wouldn’t have been enough to get a conviction. (Read more about the two types of DUIs, see What’s the Difference Between Per Se and Impairment DUIs?)
I-502 added a third type of DUI to the books—a “per se marijuana” DUI. A motorist can be convicted of a per se marijuana DUI for driving with a concentration of five nanograms or more of THC (the primary psychoactive ingredient in marijuana) per milliliter blood. So with the new law, a marijuana DUI conviction can be based on impairment or THC concentration in the blood. (Wash. Rev. Code Ann. § § 46.61.502(1), 46.61.506(2) (2016).)
I-502 also added a provision that requires the Washington State Department of Licensing to impose an administrative license suspension for anyone caught driving with a THC concentration of five nanograms or more. Previously, administrative license suspensions were applicable to only alcohol-related DUI offenses where the driver’s BAC was at least .08%. (Wash. Rev. Code Ann. § 46.20.308(5) (2016).)
(Learn about the consequences of a Washington DUI conviction.)