How can cops tell if you’re too high to drive in Washington state? What law says
Cannabis use has been legal in the state of Washington since 2012.
That doesn’t mean it’s OK to drive while high, according to Cannabis Safely, a public health education campaign launched by the Washington State Department of Health.
“Driving under the influence of cannabis is dangerous — and illegal,” the Cannabis Safely website says.
How high is too high to drive in Washington state? And how do law enforcement officers determine if you’re under the influence of cannabis?
Here’s what to know:
How high is too high to drive?
The Washington State Department of Licensing defines driving under the influence of intoxicants as “operating a vehicle while affected by alcohol, drugs or both.”
If your blood has a THC concentration of 5.00 or higher “within two hours after driving,” you will be found guilty of DUI, the Revised Code of Washington says.
“Drivers found with THC levels at or above this threshold are presumed to be in an impaired state and can be charged with DUI without the need for evidence of actual difficulties driving or functioning,” the South Sound Law Group said on its website.
Drivers under age 21 “cannot have any trace of marijuana in their blood while driving,” the Tacoma law firm said.
How can cannabis affect your ability to drive?
Driving under the influence of cannabis isn’t just illegal — it’s also a “safety risk,” according to the Washington State Liquor and Cannabis Board.
“Never get behind the wheel if you have been using cannabis,” the state board said on its website. “Using cannabis can cause drowsiness, slow reaction time and other side effects that can impair your driving, making it dangerous for yourself and others.”
How do police officers tell if you’re under the influence?
“Law enforcement often relies on roadside sobriety tests to determine impairment”, and they can arrest drivers who appear to be under the influence of alcohol or other drugs — including cannabis,” the Washington State Liquor and Cannabis Board said.
“Their testimony, as well as the results of a blood test, are used in court,” the board added.
The Washington State Patrol has specially trained members nationally certified as drug recognition experts, Trooper Daniel Mosqueda previously told McClatchy Media.
These troopers can perform a 12-step evaluation process when a driver shows signs of impairment.
This 12-step process includes an eye examination, vital sign measurements and “psychophysical tests” such as standing on one leg and touching your finger to your nose, according to the International Association of Chiefs of Police.
If you refuse to take a blood or breathalyzer test, your state-issued driver’s license or permit can be revoked for up to a year, according to the Revised Code of Washington.
In addition, your “refusal to take the test may be used in a criminal trial,” state law says.
Can I get pulled over for smelling like weed?
In Washington state, law enforcement officers cannot pull someone over — or arrest them on suspicion of DUI — for simply smelling like weed, McClatchy Media previously reported.
Instead, the Washington State Patrol relies on a “totality of indicators” to determine if a driver has used cannabis recently, Mosqueda previously told McClatchy Media.
“You’re not at risk of getting pulled over unless you show signs of impairment” such as slow speech, confusion or driving and stopping too slow, Mosqueda said.
What are penalties for driving while high in Washington?
According to the South Sound Law Group, people convicted of driving under the influence of cannabis in Washington state “face the same penalties” as those convicted of drunk drinking.
If you’re convicted of a gross misdemeanor DUI, you could spend up to a year in jail, pay up to $5,000 in fines and have your driver’s license suspended for 90 days, the Tacoma law firm said.
You could also have an ignition interlock device installed on your car at least a year and serve up to five years of probation, the South Sound Law Group said.
You can schedule a hearing to contest your license suspension within seven days of the incident, according to the Washington Department of Licensing.
If you choose not to contest the suspension, you could lose the use of your license for as long as four years, the state Licensing Department said, adding that the length of the suspension depends on the severity of the incident and whether you have prior violations.
How long should I wait to drive after cannabis use?
“Cannabis can affect your coordination, reaction time and judgment for hours after use,” the Cannabis Safely website said, so you should wait before getting behind the wheel.
Experts recommend waiting at least six hours after smoking less than 35 mg of THC, and at least eight hours after eating or drinking less than 18 mg.
If you mixed cannabis with alcohol, “You need to wait even longer,” the Cannabis Safely website said.
This story was originally published March 9, 2026 at 5:00 AM.