-- Driving Under the Influence of Marijuana (THC) - What should I know about this? Is it different for Adults and Minors? It certainly is. Here are the basics: The police could (after laws that went into effect on 12/06/2012) obtain blood samples from you without a warrant! Unbelievable! But warrants are now required for this (after 9/28/2013), especially if other illicit or even prescription drugs in the driver's system are suspected – unless there are “emergency circumstances,” where a warrant will not be required. The police need only suspect that you've consumed marijuana, so if they smell it or see a roach or a bong, etc., any paraphernalia, pipes, etc., they can get the blood draw warrant! Take a look at RCW 46.20.308, our state's Implied Consent law, which is a contract of sorts that is implied from the fact that you were granted permission to drive on our state's roads when the DOL issued you a driver's license. Most drivers are completely unaware of this agreement implied just from getting a DL. The tolerance for adults is 5.00 ng/mL but for minors (under 21) there is no threshold – it is zero tolerance for minors. For an adult who gives a blood sample with 5.00 or more in it, there's a 90-day DL suspension. If there is a second or subsequent conviction within 7 years the suspension is for 2 years. A minor who gives blood and the test comes back 5.00 or more, has a 90-day suspension, but a second or subsequent conviction for a minor over 5.00 THC within 7 years means revocation until the longer of one year or their attaining age 21. The ensuing criminal charges in the court carry additional DL suspensions and revocations. Don't be one toke over the line, eh? The corresponding, lower limit for alcohol for a minor is .02, but for pot – 0.00! regarding this Zero tolerance of THC for Minors in Washington, see RCW 46.61.503, which says: It is an affirmative defense that the defendant must prove by a preponderance of the evidence, that the defendant consumed a sufficient quantity of marijuana after the time of driving or being in physical control and before the administration of an analysis blood to cause the defendant's THC concentration to be in violation of this section within two hours after driving or being in physical control; Analyses of blood samples obtained more than two hours after the alleged driving or being in physical control may be used as evidence that within two hours of the alleged driving or being in physical control, a person had a THC concentration in violation of this section." There is no scientific proof at all that the ridiculously low Washington state THC threshold limit of 5.00 (for adults) causes any impairment whatsoever of one's coordination and hence of their ability to drive. The law is designed for revenue. It's preamble, to I-502, states: “"The people intend to stop treating adult marijuana use as a crime and try a new approach that: (1) Allows law enforcement resources to be focused on violent and property crimes; (2) Generates new state and local tax revenue for education, health care, research, and substance abuse prevention; (3) Takes marijuana out of the hands of illegal drug organizations and brings it under a tightly regulated, state-licensed system similar to that for controlling hard alcohol. This measure authorizes the state liquor control board to regulate and tax marijuana for persons twenty-one years of age and older, and add a new threshold for driving under the influence of marijuana. This means if under age 21, there is no change in the criminal law, it remains."