The AAA study focuses on Washington state over a 10-year period.

It goes without saying that operating a vehicle under the influence of anything is a bad idea. That includes your annoying in-laws who think you drive too slow, or your loudmouth friend who always wants you to do a burnout. For this article, influence refers to marijuana and with it becoming legal in more states, AAA Foundation conducted a study to see if it was having a negative effect on drivers. It seems the preliminary answer could be yes.

The study focused strictly on the state of Washington, where marijuana was legalized for recreational use late in 2012. It reviewed fatal accidents in the state over a 10-year period – five years before and five years after the legalization was official – and found a clear increase in drivers that tested positive for Tetrahydrocannabinol (THC). That’s the main component which gives marijuana its psychological effects.

Marijuana Study

As the graph shows, THC was present in approximately 8.8 percent of drivers involved in fatal accidents prior to 2013. After marijuana was legalized, that figure rose to an average of 18 percent. Boiling that down to actual numbers, 56 drivers on average were THC-positive before legalization. That average jumps to 130 after legalization. It should be noted that the study doesn’t attempt to say marijuana was the cause of these crashes. It merely indicates the increase of drivers testing positive for THC after the crash.

“This study enabled us to review a full 10-years’ worth of data about the potential impact of marijuana on driving safety – and it raises significant concerns,” said Dr. David Yang, executive director of the AAA Foundation for Traffic Safety. “Results from the analysis suggest that legalization of recreational use of marijuana may increase the rate of THC-positive drivers involved in fatal crashes.”

Marijuana Study

Marijuana is currently legal for recreational use in 11 states, and with more state governments softening on the issue, that number will likely rise in years to come.

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Fatal Crashes Involving Drivers Who Test Positive for Marijuana Increase
After State Legalizes Drug

 

Percent of THC-positive drivers has doubled since recreational use was legalized

 

TAMPA, Fla., (Jan. 30, 2020) – A concerning number of Washington state drivers involved in fatal crashes are testing positive for recent use of marijuana, according to new research from the AAA Foundation for Traffic Safety.

-Research Breakdown-

The share of drivers involved in fatal crashes, with THC in their system, doubled after marijuana was legalized in Washington state.
Since 2012, nearly one in five (18%) drivers involved in fatal crashes were positive for THC.
After legalization, the average number of THC-positive drivers involved in a fatal crash jumped from 56 per year to 130.
Although AAA – The Auto Club Group does not take a position on the legalization of marijuana, it strongly discourages people form driving under the influence.
AAA believes that states that legalized the drug should not rely solely on an arbitrary legal limit to determine if a driver is impaired. Instead, states should require chemical, behavioral and physiological evidence of marijuana impairment.
The Report

The share of drivers who, after a fatal crash, tested positive for active THC – the drug’s main psychoactive ingredient – has doubled since the state legalized marijuana in December 2012. AAA believes the increase raises important traffic safety concerns for drivers across the country, because recreational marijuana use is now legal in 11 states and Washington, D.C.

The latest AAA Foundation research found that between 2008 and 2012 – the five-year period before the drug was legal – an estimated 8.8% of Washington drivers involved in fatal crashes were positive for THC. That rate rose to 18% between 2013 and 2017.

The average number of THC-positive drivers increased, too. In the five years before legalization, an average of 56 drivers involved in fatal crashes each year were THC-positive. In the five years after legalization, the average jumped to 130. The new numbers bolster the findings of a similar report the AAA Foundation released in 2016. The study did not attempt to determine if marijuana contributed to the crashes included in its latest research. It focused only on the prevalence of drivers who tested positive for active THC.

“This study enabled us to review a full 10-years’ worth of data about the potential impact of marijuana on driving safety – and it raises significant concerns,” said Dr. David Yang, executive director of the AAA Foundation for Traffic Safety. “Results from the analysis suggest that legalization of recreational use of marijuana may increase the rate of THC-positive drivers involved in fatal crashes.”

Dangers of Marijuana-Impaired Driving

Marijuana use can inhibit concentration, slow reaction times and cloud judgment. Its effects vary by individual, but a number of studies have concluded that marijuana use impairs the ability to drive safely. Previous research suggests that users who drive high are up to twice as likely to be involved in a crash.

Legalization of Marijuana

Eleven states and Washington, D.C. have legalized marijuana for both recreational and medical use. Another 22 states have legalized it for medical use only. State legislative sessions for 2020 are getting underway and recreational use is expected to be a popular topic. The legislative interest combined with likely November ballot measures could result in additional states taking a hard look the issue.

AAA's Position

As the nation’s foremost proponent of traffic safety, AAA has long been committed to effectively reducing the number of crashes, injuries and fatalities caused by impaired driving and our policies reflect that commitment.

AAA - The Auto Club Group urges all motorists to avoid driving while impaired by alcohol, marijuana, or any other drug. AAA’s interest in the issue has less to do with the cause of the impairment, but rather the risk that’s introduced when people get behind the wheel while impaired.

"AAA opposes marijuana-impaired driving, just as we oppose alcohol-impaired driving," said Mark Jenkins, spokesman, AAA -The Auto Club Group. "Impaired driving jeopardizes public safety on our roadways regardless of whether the drug used is legal, prescribed, obtained over-the counter or purchased in a retail setting."

Enforcement
In an attempt to curtail drug-impaired driving, seven states have set legal non-zero, or “per se,” limits on the amount of THC drivers can have in their system. While well-intended, AAA believes imposing such limits is problematic because no data reliably shows what level of THC impairs driving, the chemical’s effects vary by user, and THC testing often cannot be done until hours after a crash.
AAA believes that states that have legalized the drug should not rely solely on an arbitrary legal limit to determine if a driver is impaired. They should adopt a two-pronged approach that requires:

A positive test for recent marijuana use.
Behavioral and physiological evidence of driver impairment.
Last year, a Foundation survey found:

Nearly 70% of Americans think it’s unlikely a driver will get caught by police for driving shortly after using marijuana.
An estimated 14.8 million drivers report getting behind the wheel within one hour after using marijuana in the past 30 days.
AAA's Commitment to Testing the Effects of Marijuana on U.S. Roadways

AAA is committed to educating the public about the risks of substance-impaired driving. Through AAA Foundation research, AAA is working to improve understanding on the topic and is working collaboratively with safety stakeholders to reduce the impact of substance-impaired driving related crashes.