SEATTLE — Marijuana has been legal in Washington state for more than a year, but are there more high drivers on the roads? Washington State Patrol troopers say the number of blood samples sent to toxicology labs to screen for Active THC — the ingredient that produces a psychoactive effect in pot — is up slightly but that’s because officers are trained better to spot the signs of impairment, not necessarily because there are more high drivers, WSP Sgt. Jason Hicks said. "People who make that decision to drive impaired are always gonna make that decision to drive impaired," Hicks said. "Will their drug of choice change? That's possible. Maybe they'll switch from alcohol to marijuana. But they're still gonna ingest too much and they're still gonna get behind the wheel of a car and then that's where we hope we stop them before they do something dangerous and kill someone." Sgt. Hicks said drivers high on marijuana show the same signs as somebody who's drunk. They weave across the lines and hesitate at stop lights when they turn green. "People must be able to divide their attention while driving,” Hicks said. “Impairment in any forms hinders that ability and makes that driver a danger to everyone on or around the road." Hicks said before troopers ask for a blood test, they look at the totality of the circumstances including why they stopped someone, what they saw, heard and smell. Troopers also administer a field sobriety tests just like they do with a suspected drunk driver. The test includes a test to see if a driver's eyes will cross as they move a penlight closer to their nose. If they don't cross, that could be a symptom of being high on marijuana. After all that, they make a decision on whether a motorist is impaired. "You may smoke marijuana every day and your tolerance level and what you can function at may be above 5 nanograms," Hicks said. "If I get you and I run you through everything that we normally do and I don`t see the impairment, then it's irrelevant to me how much THC is in your blood. You could have 20 nanograms. I have no legal reason to arrest you.'"