These DUI Laws Are an Irrational Hangover From Pot Prohibition

“Four years ago, Pennsylvania allowed patients suffering from any of 17 serious medical conditions to relieve their symptoms with marijuana. But there was a catch: If they used cannabis as a medicine, they could no longer legally drive.

Last week the Pennsylvania House of Representatives approved a bill that would eliminate that legal disability by requiring evidence of impairment to convict medical marijuana patients of driving under the influence (DUI). That reform points the way to a long overdue reevaluation of DUI laws that irrationally and unfairly punish cannabis consumers who pose no threat to public safety.”

“Half a dozen states, including Pennsylvania, have “per se” laws that define DUI based on the concentration of THC in a driver’s blood, while one (Colorado) allows an inference of guilt when that level reaches five nanograms per milliliter. But these laws don’t make sense”

“Because THC, unlike alcohol, is fat-soluble rather than water-soluble, there is no clear or consistent relationship between THC in the blood and THC in the brain, which means THC blood levels do not correspond neatly to degrees of impairment. Complicating the situation further, individual responses to a given dose of THC vary widely, especially when you compare occasional marijuana users to regular consumers, who may develop tolerance to the drug’s effects or learn to compensate for them.”

“Even states that have legalized marijuana for all adults 21 or older do not necessarily have rational DUI laws. Illinois, Nevada, and Washington make drivers automatically guilty at THC blood levels that regular consumers commonly exceed even when they are not impaired, while Michigan still has a zero tolerance law that treats any amount of THC as conclusive DUI evidence.”