As of Dec. 6, marijuana will be legal to use in Washington state. The number of people driving while stoned is certain to increase.
And that has law enforcement officials in Washington -- as well as in Colorado, where pot was also legalized -- concerned about keeping high drivers off the road.
Washington's voter-approved law does change driving-under-the-influence provisions by setting a new blood-test limit for marijuana. It's a limit law enforcement is now training to enforce while defense lawyers are preparing their challenges.
"We've had decades of studies and experience with alcohol," said Washington State Patrol spokesman Dan Coon. "Marijuana is new, so it's going to take some time to figure out how the courts and prosecutors are going to handle it."
Police must observe signs of impaired driving before pulling a driver over, Coon said. If the trooper or officer suspects marijuana use, blood would be drawn by a medical professional. Tests above 5 nanograms would automatically subject the driver to a DUI conviction.
But what does that mean in terms of pot consumption?
The verdict is out. Some believe this level is comparable to a blood-alcohol level of .08, others see it as overly strict. There is clear disagreement.
Most convictions for stoned driving currently are based on police observations, followed later by a blood test.
"There is not yet a consensus about the standard rate for THC (marijuana) impairment," said Betty Aldworth, outreach director for Colorado's Campaign to Regulate Marijuana Like Alcohol.
According to the National Highway Traffic Safety Administration, peak THC concentrations are reached during the act of smoking, and within three hours the levels fall to less than 5 nanograms per milliliter of blood.
Those who believe the level is unfair claim that medical marijuana users (as well as regular recreational users) would hit that level because the drug will be in their systems although they are not necessarily high at the time.
They also worry about the law's zero-tolerance policy for those under 21. College students who are heavy pot users could wind up convicted even if they weren't impaired at the time. This would give them a police record and some might lose college loans.
Jon Fox, a Seattle-area DUI attorney, said he's interested in challenging Washington's new standard as unconstitutional. He plans to argue that, under due process principles, people are entitled to know specifically what is prohibited. He said if scientists can't tell someone how much marijuana it will take for him or her to test over the threshold, how is the average pot user supposed to know?
That's a good enough question that it might well result in a number of driving-while-stoned convictions being overturned.
All this needs to be figured out, and figured out quickly. Lives are literally at stake.