4/20 is an unofficial holiday celebrated annually by cannabis users across the US. The term “420” originated in 1971 and has been popularized over the years by several mainstream TV shows and movies. In 2017, Washington state saw an almost 80% increase in pot sales on April 20th when compared to April 1st – 19th of that same year.
Since the legalization of recreational marijuana use in 2012, Washington State has struggled to understand the effects marijuana use has on driving. The implementation of testing methods that measure THC levels in the blood – as well as tests for mental and physical impairment – are in the works, but aren’t accurate or reliable yet.
As with alcohol, marijuana use has different effects on different people – part of the reason Washington is having such a difficult time creating tests that give an accurate assessment of how impaired a driver really is. THC concentration in the blood is currently being used as a measurement of impairment (much like .08 blood alcohol concentration is), but many argue that is not an accurate method to use. Regardless of the reliability of this measurement, Washington law currently states that if you have a THC concentration of 5.00 nanograms or higher per milliliter of blood within two hours after driving, you are guilty of DUI.
With April 20th fast approaching, it’s important to remember that per RCW 46.61.502 you can be charged with DUI if you are driving while under the influence of marijuana. The state does not need to prove that you had a blood THC concentration of 5.00 nanograms per milliliter, only that you were substantially affected by the drug while driving.
So, if you’re going to celebrate 4/20 this year, make sure you don’t get behind the wheel. Washington State Troopers and local law enforcement will likely have increased patrols for marijuana-related impaired driving.