EVERETT — A lot of the rules surrounding marijuana have changed here in recent years.
One hasn’t. It’s still illegal to drive while high.
Statewide, marijuana was found in 28 percent of blood samples taken in impaired driving cases in 2014, according to data provided by the Washington State Patrol. That number has gone up and down over the past five years but was higher last year than in 2012 or 2013.
The data don’t include cases where drivers failed a breath test for alcohol and no blood sample was taken.
Most often, marijuana is seen in impaired driving cases combined with other substances, including alcohol and illegal drugs, police say. That’s also true in crashes that result in felony charges, according to Snohomish County prosecutors.
“Alcohol continues to be far and away the bigger problem,” said Bob Calkins, who until recently was the State Patrol spokesman.
In thousands of impaired driving cases every year, marijuana is the most frequent factor for people younger than 21, a State Patrol report says.
When people test positive for recent marijuana use, roughly half of them are found to be above the legal limit of 5 nanograms per milliliter of blood, the report says.
The numbers don’t allow for crystal-clear interpretation. For example, if a trooper has enough evidence that someone is drunk, a follow-up test for marijuana might not happen, Calkins said. Unlike a breath test for alcohol, a blood test for marijuana use generally requires consent or a search warrant signed by a judge.
Obtaining a judge’s permission can take hours — a window in which marijuana metabolizes. Troopers also have more training now on recognizing marijuana impairment than they used to, a possible factor in the bump in arrests, Calkins said.
“We’ve always arrested people for drugs other than alcohol,” he said. “Marijuana is nothing new.”
Police and prosecutors can build a criminal case when a driver’s blood shows recent marijuana use. Some agencies outside law enforcement track marijuana use more broadly — counting in their data the month-long period when pot remains in someone’s system but is no longer impairing their driving.
That makes it difficult to compare statewide and federal statistics on deaths and injuries.
The Snohomish County sheriff’s collision investigation team hasn’t seen an uptick in cases in which suspects have recently consumed both alcohol and pot, spokeswoman Shari Ireton said.
That doesn’t mean it’s not happening, though. Alcohol impairment’s symptoms, such as the smell and slurred speech, are easier to detect on scene to establish probable cause for an arrest. With marijuana, smoke might dissipate and paraphernalia might not be visible in the car.
Still, marijuana has been a factor in several fatal wrecks in the county in recent months.
Deputy Prosecuting Attorney Tobin Darrow has been charging felony collision cases in Snohomish County since 2009.
“I would definitely say that in the last year, I have been referred quite a few more cases where the impairment is at least partially marijuana,” he said.
The most common combination he sees in felony crashes is marijuana and alcohol. Even if both substances are present but below their respective legal limits, together they can support an argument of impairment, he said.
Or, as Calkins put it, “A little bit of alcohol and a little bit of marijuana makes for a really terrible, very dangerous, driver.”
Rikki King: 425-339-3449; email@example.com.