Driving High; What Police Are Looking For

With all the new pot shops opening up around the state, law enforcement officers are now on the lookout, more than ever, for people driving under the influence of marijuana.

"They're having trouble driving so we pull them over and we're seeing they're having trouble focusing, really slow to react and we're having to repeat instructions," said Lattin.

The process for checking for a driver driving high starts out just the same as a drunk driving test.

First it's the standard 'follow my finger' routine known as the Horizontal Gaze Nystagmus test which typically checks for alochol.

Once the officer can eliminate the possibility of the impairment being alcohol-related and they think it is marijuana, they can take the person to the station and get a search warrant from a judge for blood.

"We'll then take them to the hospital and draw blood," said Lattin.

The blood is sent to a toxicology lab and what experts are looking for is active THC in the blood.

The same way .08 is the legal limit for alcohol, a reading of 5 nanorgram THC blood level automatically means you're driving impaired in the state of Washington.

Lattin said even if your THC level is below the legal limit, marijuana affects people differently and officers can still testify is court that you were in fact impaired despite the numbers.

Lattin said it's not clear how many hours needs to go by before you are fully sober to drive after smoking weed.

"The crazy thing is I can't give any advice to that. This is all new ground. With alcohol, we can say don't drive impaired because we know a lot about alcohol but with marijuana these are some unknown qualities so I can't tell you. You probably shouldn't drive if you've been smoking marijuana," said Lattin.

There have been more 41 fatal crashed statewide with a marijuana-positive driver involved so far this year.

A 'Drive High, Get a DUI' campaign started at the beginning of this month and will end Sunday.