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Study shows medical marijuana laws reduce traffic deaths

Daily Dose 2011-12-04 2 comments

Study shows medical marijuana laws reduce traffic deaths

Lower consumption of alcohol among many contributing factors to fewer fatalities on the road

A groundbreaking  study shows that laws legalizing medical marijuana have resulted in a nearly nine percent drop in traffic deaths and a five percent reduction in beer sales.


Our research suggests that the legalization of medical marijuana reduces traffic fatalities through reducing alcohol consumption by young adults. – Daniel Rees, professor of economics at the University of Colorado Denver who co-authored the study with D. Mark Anderson, assistant professor of economics at Montana State University.


The researchers collected data from a variety of sources including the National Survey on Drug Use and Health, the Behavioral Risk Factor Surveillance System, and the Fatality Analysis Reporting System.

The study is the first to examine the relationship between the legalization of medical marijuana and traffic deaths.

“We were astounded by how little is known about the effects of legalizing medical marijuana,” Rees said.

“We looked into traffic fatalities because there is good data, and the data allow us to test whether alcohol was a factor.”

Anderson noted that traffic deaths are significant from a policy standpoint.

“Traffic fatalities are an important outcome from a policy perspective because they represent the leading cause of death among Americans ages five to 34,” he said.

The economists analyzed traffic fatalities nationwide, including the 13 states that legalized medical marijuana between 1990 and 2009. In those states, they found evidence that alcohol consumption by 20- through 29-year-olds went down, resulting in fewer deaths on the road.

The economists noted that simulator studies conducted by previous researchers suggest that drivers under the influence of alcohol tend to underestimate how badly their skills are impaired. They drive faster and take more risks.

In contrast, these studies show that drivers under the influence of marijuana tend to avoid risks. However, Rees and Anderson cautioned that legalization of medical marijuana may result in fewer traffic deaths because it’s typically used in private, while alcohol is often consumed at bars and restaurants.

“I think this is a very timely study given all the medical marijuana laws being passed or under consideration,” Anderson said. “These policies have not been research-based thus far and our research shows some of the social effects of these laws. Our results suggest a direct link between marijuana and alcohol consumption.”

The study also examined marijuana use in three states that legalized medical marijuana in the mid-2000s, Montana, Rhode Island, and Vermont. Marijuana use by adults increased after legalization in Montana and Rhode Island, but not in Vermont. There was no evidence that marijuana use by minors increased.

Opponents of medical marijuana believe that legalization leads to increased use of marijuana by minors.

According to Rees and Anderson, the majority of registered medical marijuana patients in Arizona and Colorado are male. In Arizona, 75 percent of registered patients are male; in Colorado, 68 percent are male. Many are under the age of 40. For instance, 48 percent of registered patients in Montana are under 40.

“Although we make no policy recommendations, it certainly appears as though medical marijuana laws are making our highways safer,” Rees said.

By Bob Berwin  |  Published in Summit County Citizens Voice


  1. yankee2

    I might add that, during those 45 years, when I was stoned almost every single day, I earned 3 college degrees, including a graduate degree, got very good grades, and held down some very good jobs after college. I also have a successful marriage, and have been a successful parent to 2 well-balanced, talented children. Smoking pot, and being stoned most of the time did not prevent me from being fairly successful, if I say so myself, in life. However, according to some, because I’m a pothead, I must be the scum of the earth. Not so.

  2. yankee2

    I’ve smoked pot my entire adult life. I have driven stoned almost every day. In 45 years, my driving record has been extremely good, involving only 6-8 tickets and 5-6 accidents, NONE of which were judged to be my fault. You’all will have to take my word on this, but in that 45 years, every single ticket and accident occurred during the tiny 10% of the time I was straight! ALL those incidents occurred while I was straight! When I was stoned, which was 90% of the time, I NEVER got a ticket OR had an accident.

    That explanation for safe stoned driving, that “drivers on alcohol don’t recognize their impairment, and not only fail to compensate for it, by driving more deliberately and slowly, but actually drive more carelessly and recklessly, leading to more and more severe accidents, while drivers on marijuana DO recognize their impairment, which however is far less intense than in the case of alcohol, and DO compensate for it, by driving more carefully and slowly, leading fewer and less lethal accidents,” is originally from a 1993 USDOT study of the effect of THC on driving skill.

    That sound scientific study also explained that “Drivers under the influence of alcohol experience an increase in aggression, and a decrease of inhibition, which leads to reckless driving and more accidents, whereas drivers under the influence of THC experience a reduction of aggression and an increase in inhibition, a combination which leads to more careful driving and fewer accidents. It was even suggested that drivers under the influence of THC frequently OVERCOMPENSATE for impairment perceived to be greater than it really is, leading to driving that is actually SAFER even than driving straight (straight drivers often drive carelessly). That 1993 study found that according to the standard used for alcohol, drivers under the influence of even a moderately strong dose of THC (300 mg – which is about 1/3 gram, which would be equivalent to about 1 gram of the strongest pot, which is in fact more than most people smoke at a sitting) would NOT be considered impaired! All that research, essentially all that casts marijuana in a good light (which is most of it) has been suppressed, and is ignored by policymakers.