In States that Legalized Marijuana, the Road to Auto Accidents Isn’t Paved with Weed
By Jill D. Ponto-Miller
With 23 states and the District of Columbia having legalized medical marijuana and 4 states legalizing its recreational use for those 21 and older, a cadre of Cassandras prophesized impending doom for America’s roadways.
Too many people already drive drunk, they reasoned. We can’t add folks high on ganga, recklessly motoring around our cities, causing accidents and harming themselves and others, to the mix, they said.
It is illegal to drive anywhere in the United States while impaired by marijuana. And “impaired” is the key word. Because THC can remain in one’s body, and be found in blood and urine samples several weeks after ingestion, it is imperative to know where actual impairment begins and ends. And states are all over the board.
Some require subjective signs of impairment in order to prosecute a driver.
Some states have a zero tolerance policy. These states use a per se template: there’s either marijuana in your system or there isn’t. You’re prosecuted or you aren’t.
And others limit how much active THC can be found in one’s system, designed to be comparable to the .08 limit for drunken driving. Five parts per billion of THC is the threshold in Colorado, Washington and Montana.
Arizona has taken the greatest steps to form a distinction in impaired versus unimpaired driving; its definition of impairment is the most refined.
Marijuana produces 2 distinct compounds—one psychoactive, the other not. Because THC can remain and be detected in a person’s body for several weeks after its use, blood testing provides the best barometer. A test negative for the psychoactive compound is considered to be at the legal threshold for driving. The active compound dissipates within hours of ingestion.
The Arizona Supreme Court established that standard in April 2014 when it overturned a 2013 State Court of Appeals decision.
The appellate decision upheld the right to prosecute pot smokers even without objective or subjective evidence of impairment, regardless of which compounds were found.
The earlier decision didn’t sit well with pot advocates. Prosecutors had warned anyone using THC in Arizona simply not to drive, or risk facing charges. The advocates argued this interpretation of the law criminalized their legal use of the drug after voters had approved it in 2010. The Supreme Court agreed and its decision removed the prosecutors’ threat.
Experts were initially concerned that legalized marijuana would lead to significantly higher traffic fatalities. However, testing has been inconclusive.
Studies have shown that marijuana can slow decision making while driving, decrease peripheral vision and impede multitasking. But it was also learned that unlike drunken drivers, pot users tend to be aware of their impairment and compensate by driving more slowly and engaging in less risky driving.
In Washington in 2013, a 25% increase in drivers testing positive for pot was noted. This study comprised the first year of legalized marijuana in the state. However there was no corresponding increase in traffic accidents or fatalities.
Another study noted virtually zero driving impairment in habitual pot users.
Traffic safety experts expecting a huge increase in accidents nationwide have conceded that so far this trend has not been realized. Longer running studies are, of course, anticipated.
It seems there is one less thing for the anti-marijuana Chicken Littles to fret about. They can relax and take comfort in the statistics gathered thus far: it appears a band of hardcore, out of their gourds stoners are not on every street and highway, an accident waiting to happen.