Sadly, it is well known that with holiday cheer comes an increase in rates of impaired driving. Recent high profile crashes connected to alcohol have not only devastated lives but, this time, have also become a catalyst for change.

In efforts to make our roads safer, lawmakers in Olympia recently increased consequences for driving under the influence (DUI). Drunk drivers now face additional penalties such as mandatory ignition interlock devices and automatic vehicle impound. Complicating things, however, has been the legalization of marijuana, which has corresponded to nearly a 50% increase in “stoned” drivers on our roads since January.

Increasing DUI penalties to better fit the crime can help deter would-be drunk drivers. Now, it is not only important that Washingtonians understand these rules also apply to marijuana , but to acknowledge that drugged driving is a problem that needs to be better understood.

The jump in drugged driving rates in Washington is troubling. Of additional concern is that one quarter of those cases are for minors under age 21.  While years of public health messaging and focused police enforcement have made it clear to youth and adults alike that, “drinking and driving don’t mix” and, “you don’t have to be buzzed to be busted,” driving under the influence of marijuana now must be given the same attention.

Although it can have the same negative outcomes as drunk driving, marijuana impaired driving is more challenging to educate about than alcohol. The law states that five nanograms of active delta-9-THC per liter of whole blood is the standard for determining impaired driving.  However, this level is somewhat arbitrary because every individual is affected by marijuana differently.  Chronic users may be less impaired than first time users even after smoking the same amount.  The science remains unclear.

What is clear, however, is that marijuana use impairs motor coordination and decision-making.  If a driver is stopped for suspicious driving behavior (as with alcohol) and suspected of being under the influence of marijuana, they will be taken to a hospital for a blood draw because there is not yet a marijuana equivalent to a breathalizer.

It is important to understand that mixing marijuana with alcohol or other drugs more than doubles impairment.  Youth face a zero tolerance policy and are legally impaired for having any amount marijuana in their system.  Marijuana edibles can take hours to create impairment, sometimes fooling users into thinking they are safe to drive immediately after ingestion.  The situation might become more challenging when marijuana retail stores open and introduce higher THC concentration marijuana, butane hash oil for discreet vaporizing, and marijuana-infused candies which can make overdose (not death, but excessive ingestion) easier and attract more youth.

In the first half of 2013, 27% of all impaired driving cases in Washington tested positive for THC (up from 19% in 2012). Although waiting at least four hours to drive after smoking marijuana (longer for edibles) is recommended by some, the best advice this holiday season may be to simply not  drink or smoke and drive.

Mercer Island Police Chief, Ed Holmes