Tuesday, April 22, the Arizona Supreme Court ruled that a driver cannot be charged with driving under the influence of marijuana simply because traces of the drug are found in their system; there has to be proof that the driver is actually impaired. Before this decision, a driver who had legally used marijuana within the last 30 days could still have test results that indicated the presence of marijuana, and this was enough to land them a DUI charge.

The metabolite Carboxy-THC can reside in the blood stream for up to a month after marijuana use, far after the time that marijuana use could actually impair someone, according to officials in the case. One court justice even pointed out that prosecutors consented to the fact this particular metabolite is not responsible for impairment. The prevailing decision from the state Supreme Court was that the presence of Carboxy-THC cannot automatically trigger a charge of driving under the influence. This opinion was not shared by all the justices, however. One judge said, "The difficulty of detecting drug impairment justifies a flat ban." She cited the fact that Hydroxy-THC, which does impair drivers, turns into Carboxy-THC so rapidly that this is the substance officers must test for.

This is a legal battle that is occurring in other states as well, where recreational or medical marijuana has been legalized. Debate is still swirling around the issue of whether a zero-tolerance police unfairly denies driving privileges to legal marijuana users, or if THC tests are an imperfect but necessary measure to ensure that truly impaired drivers stay off the roads. As states can vary a great deal in how they handle DUI charges, the counsel of a local DUI lawyer will be invaluable for your case. To learn the DUI or DWI defenses available in your state, be sure to contact a DUI attorney today!