Marijuana » Marijuana News

Legalized Pot Means Less Traffic Fatalities

Pot in the driver's seat.


  • Courtesy photo

Marijuana seems to be in a bit of a traffic jam lately. One area that folks who oppose marijuana use have focused on is drugged driving. As they lose more ground to public opinions and legalization laws, they start talking about danger behind the wheel and ask how we’re going to keep the users from running into and breaking things while in a haze.

For instance, a recent headline at in the public health information section blares out: “Fatal car crashes involving pot use have tripled in the U.S., study finds.”

Oh my god, the potheads are driving around in a death race that will destroy us all! The story covers statistics showing that in 1999 metabolites from marijuana were present in the blood of 4 percent of drivers involved in a fatal accident; and that by 2010 that number had risen to 12 percent. 

That’s easy enough to grab and run with when you’re fighting the scourge of drugs. However, let’s dig a little deeper. Metabolites of cannabinoids in marijuana are detectable in blood as long as a month after use. The presence of metabolites is not an indication of impairment. The researchers mentioned that in an endnote to their report. 

“The prevalence of nonalcohol drugs reported in this study should be interpreted as an indicator of drug use, not necessarily a measurement of drug impairment,” they wrote.

The Michigan Supreme Court actually established that legally in our state in the 2010 decision on People v. Feezel. They ruled that the presence of metabolites in a driver’s blood is not illegal and doesn’t indicate impairment. Metabolites are what remain after the body processes cannabinoids.

“What you get after the THC is metabolites,” says attorney Matt Abel, executive director of Michigan’s branch of the National Organization for the Reform of Marijuana Laws. “The high is long gone. Marijuana doesn’t seem to be an impairing substance in the way that alcohol is. Studies have shown that people seem to be more cautious under the influence of marijuana. … People who are regular users can likely drive unimpaired in less than an hour after they’ve smoked.”

There’s a lot of debate about whether it’s one hour or three hours or more. And there is a lot of debate on how much THC in someone’s blood means that they’re intoxicated. However, it’s clear that the presence of metabolites do not indicate that someone is high or an impaired driver.

Not only are they not impaired, but according to a study released in 2012 by the U.S. National Highway Traffic Safety Administration, “the only significant effect that marijuana has on operating a motor vehicle is slower driving.” In most cases that’s a good thing. 

Furthermore, there is evidence that legalizing medical marijuana corresponds with a drop in traffic fatalities. A study released in 2011 by researchers at the University of Colorado in the 13 states that legalized medical marijuana between 1990 and 2009, traffic fatalities have dropped by about 9 percent. Yes, that’s right, 9 percent.

Here’s the part that your local party store owner won’t like: The same study found that beer sales dropped in those states by about 5 percent. Apparently more pot means less beer and fewer traffic deaths.

“Our research suggests that the legalization of medical marijuana reduces traffic fatalities through reducing alcohol consumption by young adults,” said economics professor and co-author Daniel Rees in a press release. “We looked into traffic fatalities because there is good data, and the data allow us to test whether alcohol was a factor. … Although we make no policy recommendations, it certainly appears as though medical marijuana laws are making our highways safer.”

So we have two studies. One says that an increasing number of drivers in traffic fatalities have evidence of marijuana use in their blood, but not necessarily marijuana intoxication. The other says that where medical marijuana is legal there is a drop in traffic fatalities. They seem to contradict each other. Maybe there are other factors they aren’t considering. Maybe people are using marijuana sometimes and alcohol at other times. That would explain the presence of metabolites in the blood of drivers. Maybe it’s because people are using both substances together.

“It’s alcohol that induces risky behavior rather than marijuana,” Abel says. “When used in combination, it’s still the alcohol that’s inducing the risky behavior.”

The University of Colorado study also concluded: “Evidence from simulator and driving course studies provides a simple explanation for why substituting marijuana for alcohol may lead to fewer traffic fatalities. These studies show that alcohol consumption leads to an increased risk of collision. Even at low doses, drivers under the influence of alcohol tend to underestimate the degree to which they are impaired, drive at faster speeds, and take more risks. In contrast, simulator and driving course studies provide only limited evidence that driving under the influence of marijuana leads to an increased risk of collision, perhaps as a result of compensatory driver behavior.”

Apparently marijuana users know they’re high and become more cautious. Alcohol users behave badly behind the wheel. This is not an endorsement for driving while stoned. People should not get behind the wheel while impaired by anything. However, despite the headlines, there is not an increase in traffic fatalities caused by marijuana use. In fact, the UC study found that, in Michigan, traffic fatalities dropped by a full 10 percent. And that overall, in medical marijuana states, they, “found evidence that alcohol consumption by 20- through 29-year olds went down, resulting in fewer deaths on the road.”

That’s a concern for alcohol retailers. As far as I can tell, those are the years when people tend to set their relationship with alcohol. If they don’t drink much then, there’s less chance they’re going to drink a lot later. They might continue their marijuana use, which by most evidence is safer and healthier.

Regarding the big increase of drivers in fatal accidents testing positive for indicators of marijuana use, first of all I have sympathy for the families of the deceased. And I don’t doubt that some of these drivers were actually high on marijuana. However, I believe the big increase in marijuana indicators represents the fact that law enforcement is more actively testing for marijuana, and there are more marijuana users out there now. In particular, people with medical conditions who were never interested in getting high in the first place. Yes, they have metabolites in their bloodstream, but in most cases they aren’t impaired.

“Police resources and knowledge has increased over time,” says Abel. “There are a lot more people with metabolites in their bloodstream. Those folks get into crashes the same proportion as everybody else.”

Don’t let the naysayers jam you up in a rush to judgment when the issue has nuances they don’t see. As Jimi Hendrix said in “Crosstown Traffic,” “so hard to get through to you.” 

We welcome readers to submit letters regarding articles and content in Detroit Metro Times. Letters should be a minimum of 150 words, refer to content that has appeared on Detroit Metro Times, and must include the writer's full name, address, and phone number for verification purposes. No attachments will be considered. Writers of letters selected for publication will be notified via email. Letters may be edited and shortened for space.

Email us at

Support Local Journalism.
Join the Detroit Metro Times Press Club

Local journalism is information. Information is power. And we believe everyone deserves access to accurate independent coverage of their community and state. Our readers helped us continue this coverage in 2020, and we are so grateful for the support.

Help us keep this coverage going in 2021. Whether it's a one-time acknowledgement of this article or an ongoing membership pledge, your support goes to local-based reporting from our small but mighty team.

Join the Metro Times Press Club for as little as $5 a month.