The state of Washington recently legalized marijuana for recreational use. One of the main concerns of legalizing marijuana is that more people run the risk of driving under the influence of marijuana. The new law legalizing marijuana is careful to explain that driving under the influence of marijuana will be treated the same as driving under the influence of alcohol. In fact, a recent article in The Seattle Times claims that “stoned driving, (according to researchers), is simply less dangerous (than drunk driving).”

Smoking and driving photo by xxxology
Recreational Marijuana and Driving
Since marijuana became legal in Washington State, distinctions between the results for field sobriety tests given to drunk drivers and high drivers have become paramount. A Washington State field sobriety test usually consist of checking horizontal gaze nystagmus – rapid involuntary movements of the eye / eye coordination – by seeing if the suspected drunk, or, in this case, high, driver can follow an object, like a pen, with their eyes and without moving their head. Other standard field sobriety tests (SFST) may include:
- The Walk-and-Turn (WAT) test – where the individual is expected to walking in a straight-line heal-to-toe, turn back on one foot and do walk back.
- The One-Leg Stand (OLS) test – where the individual must stand on one foot, keeping the other foot approximately 6 feet off the ground for 30 seconds.
Drunk or Stoned?
The article, “Who’s, more dangerous: drunken or stoned driver?” gathers supporting evidence from a 2012 study published in the journal Psychopharmacology that states, “only 30 percent of people under the influence of THC, the active ingredient in marijuana, failed the field test. And its ability to identify a stoned driver seems to depend heavily on whether the driver is used to being stoned.”
The article is not making the case for so-called stoners, but rather is drawing a comparison between two recreational activates – smoking pot and drinking alcohol – one of which is a nationally accepted form of recreation and the other is still viewed by many as an illegal and dangerous activity. By drawing the comparison, the article is able to demonstrate the relative safety of driving under the influence of marijuana in comparison to driving under the influence of alcohol.
Another example that The Seattle Times article presents is that of “a 21-year-old driver on his first bender and (that of) a hardened alcoholic” stating that “both wobble on one foot” during a sobriety test, where as “the same is not necessarily true of a driver who just smoked his first joint and the stoner who is high five days a week.”
The Conflict Over THC Breathalyzer Tests
So, a person driving under the influence of marijuana may be able to pass standardized field sobriety test, but can they pass a Breathalyzer? The real concern in distributing a Breathalyzer to a person suspected of driving high is how to measure the toxicity level of marijuana. How much is too much? The current limit for a person driving under the influence of marijuana is 5 nanograms per milliliter of blood, which is 5 parts per billion.
A European study suggest that a limit of 5 nanograms is far too high claiming that “if you smoke often enough, your blood-THC content might still be 5 nanograms per milliliter a day after you last lit up.” An individual may have 5 nanograms of THC in their system from frequently smoking marijuana, but that does not necessarily indicate that the individual is high – which, in theory, is the contributing factor to reckless driving. The study suggests that the limit be changed to 1 nanogram per milliliter “because the THC builds up in fatty tissue and is release slowly, (and) such a limit may ensure frequent users who may not be high.”
Expunging Your Marijuana DUI
While the terms of how to measure driving under the influence of marijuana are still being debated, one thing is certain – a DUI, whether for driving under the influence of alcohol or for driving under the influence of marijuana, will permanently remain on your criminal record until you have the DUI expunged, which, in Washington, is referred to as vacating. To see if your Washington DUI is eligible for expungement, take this free online eligibility test.