A study released Tuesday by the University of Colorado Denver indicates that the legalization of medical marijuana reduces alcohol consumption and, as a result, alcohol-related traffic deaths without a corresponding increase in deaths caused by stoned drivers.

The study, hailed as “groundbreaking” by the University, is the first to examine the effect of legalizing medical marijuana on the prevalence of traffic fatalities. Researchers analyzed traffic fatalities nationwide, and in those states that have legalized medical marijuana they found that alcohol consumption went down among those 20 to 29 years old, resulting in fewer deaths on the road.



The study noted past research that suggests drivers under the influence of alcohol and marijuana both experience reduced skills and slower reaction times but that those driving under the influence of alcohol are unaware of their reduced skills and actually drive faster and more recklessly than when they are sober. Stoned drivers, on the other hand, seem to know they are stoned and they slow down, increase the distance between them and the car ahead of them and avoid risky maneuvers. The study noted that people who are stoned are also less likely to drive in the first place than people who are drunk.

Stoned drivers, on the other hand, seem to know they are stoned and they slow down, increase the distance between them and the car ahead of them and avoid risky maneuvers.

From the study:

To date, 16 states have passed medical marijuana laws, yet very little is known about their effects. Using state-level data, we examine the relationship between medical marijuana laws and a variety of outcomes. Legalization of medical marijuana is associated with increased use of marijuana among adults, but not among minors. In addition, legalization is associated with a nearly 9 percent decrease in traffic fatalities, most likely to due to its impact on alcohol consumption. Our estimates provide strong evidence that marijuana and alcohol are substitutes.

“Every objective study on marijuana has concluded that it is far safer than alcohol for the user and society,” said Mason Tvert, executive director of Safer Alternative For Enjoyable Recreation (SAFER) and coauthor of the book, Marijuana is Safer: So why are we driving people to drink? (Chelsea Green, 2009). “It should come as little surprise that when we allow adults to make the safer choice to use marijuana it results in less drinking and fewer alcohol-related problems,” he said in a press release.

Tvert is one of two formal proponents of a 2012 statewide initiative campaign to make marijuana legal in Colorado and regulate it and tax it similar to alcohol.

From CU’s press release:

A groundbreaking new 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,” said 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.

Tvert said he didn’t think people should drive if they are impaired by any substance but that giving people the choice to use marijuana instead of alcohol would save lives.

“The real story is that by just making marijuana legal for a small segment of society, there is significantly less alcohol use and less alcohol related deaths,” Tvert told the Colorado Independent.

He said that nationally alcohol abuse kills about 80,000 Americans a year, not counting those killed by drunk drivers or alcohol-related violence.

“The real story is that by just making marijuana legal for a small segment of society, there is significantly less alcohol use and less alcohol related deaths.”

“There is a vast amount of evidence that alcohol contributes to violence, everything from bar fights to domestic violence to larger scale riots and upheavals at public events. There is no evidence that marijuana has ever contributed to violence or to a single death,” Tvert said.

He noted that nationally, automobile accidents are the leading cause of accidental death but that in Colorado prescription drug overdoses are the leading cause of accidental death. He suggested that the more widely marijuana was legalized and available, the less likely prescription overdoses would be, a sentiment borne out by research.