States made marijuana use legal. Now they should get it off the road.

Washington Post -   This holiday season, police departments across the country will repeat their laudable annual efforts to deter drunken driving. Yet more than a decade after states began legalizing recreational marijuana, or cannabis, effective policies to counter driving while high on it don’t exist. There are several reasons why the danger from cannabis-impaired drivers has so far gone largely unaddressed, and why the threat is increasing.

The first challenge is that when police stop a driver suspected of driving under the influence, they have no equivalent of a roadside breathalyzer test for detecting cannabis intoxication. There is no widely agreed upon, valid standard for rapidly and accurately measuring the amount of THC — cannabis’s psychoactive agent — in a person’s body. Even taking a suspected THC-intoxicated driver to the police station for a blood or urine test would be pointless: THC is lipophilic, meaning it hangs around in fat cells long after it has been consumed. That can skew testing, producing a positive result in a blood or urine test even though the person who consumed the cannabis is no longer high.

The second challenge: Getting high has become incredibly cheap in some states. For example, the median retail price for a gram of cannabis flower in Oregon is now $3.33 — about a 70 percent drop since 2016. It used to be the case that a gram would make about three joints, but these days it’s common to see one-gram pre-rolled joints in dispensaries. Some stores in Michigan have advertised ounces for $25, which, including taxes, works out to about $1 per gram.

Third, policymakers and advocates in many states did not follow up marijuana legalization with adequate regulations for the industry they created, the higher potency products it produced or the aggressiveness or accuracy with which those products were marketed. How states would detect and deter cannabis-impaired driving is one of many policy problems that did not receive sufficient thought.