Proponents of legalizing marijuana have long argued that criminalization of the drug causes more problems than it solves. For instance, taxpayers spend between $7.5 billion and $10 billion a year on arresting and prosecuting Americans for marijuana-related crimes. Supporters of legalized marijuana maintain that this money would be better spent cracking down on violent criminals.
Now, pro-legalization backers have yet another point in their favor: According to a new study from the University of Colorado-Denver, the 16 states that have legalized medical marijuana have seen an average 9 percent drop in traffic deaths since their medical marijuana laws took effect. The study analyzed data from 1990 through 2009.
“We went into our research expecting the opposite effect,” says study co-author Daniel Rees, a professor of economics at the University of Colorado-Denver. “We thought medical marijuana legalization would increase traffic fatalities. We were stunned by the results.”
When it comes to traffic safety, can marijuana really save lives?
Is marijuana an alcohol substitute?
It’s long been known that alcohol is a primary contributor to deadly car crashes. According to estimates from the Insurance Institute for Highway Safety, drivers with a blood-alcohol level above 0.15 percent are 385 times as likely to be involved in a fatal crash as sober drivers are. In every state, the legal limit for driving while intoxicated is 0.08 percent.
The University of Colorado-Denver study found that the increase in legal use of medical marijuana often leads to a reduction in alcohol consumption. The study cites data from the Beer Institute, an industry trade group, indicating that beer purchases go down by an average of 5 percent after medical marijuana laws are passed. In these states, the researchers theorize, some people are smoking marijuana rather than downing booze.
A 2009 study from the University of California, Berkeley, backs up that finding. Four of every 10 patients at the university's medical marijuana dispensary said they used marijuana to curb alcohol cravings.
Are high drivers better than drunken drivers?
The differences between drivers under the influence of alcohol and those who’ve smoked weed are stark, says Mason Tvert, executive director of the marijuana legalization advocacy group SAFER (Safer Alternative for Enjoyable Recreation).
“People who abuse alcohol take more risks, drive faster and are less likely to recognize that they’re impaired,” Tvert says. “They feel like Superman when they’re drunk.”
By contrast, motorists who’ve puffed pot “drive slower, are less likely to take risks, and are more likely to recognize when they’re impaired and decide not to drive,” he says.
Studies support Tvert’s view: A clinical trial conducted in Israel compared the simulated driving skills of people who’d consumed alcohol and those who’d smoked marijuana. The researchers found that alcohol caused these people to speed up their driving, while smoking marijuana prompted the drivers to slow down. An analysis by the U.S. Department of Transportation found marijuana rarely is the only drug found in the bodies of drivers who've died in car crashes.
Is driving under the influence of marijuana safe?
Mothers Against Drunk Driving (MADD) advocates against impaired driving of any form, and that includes smoking marijuana and getting behind the wheel. Emily Tompkins, MADD's executive director for Colorado, says the group is keeping tabs on marijuana legalization and how it affects traffic safety.
MADD isn't interested in determining how much marijuana someone can consume to remain within a legal limit, but Tompkins urges people who smoke marijuana (medical or otherwise) to be aware of when their driving is impaired. Tompkins claims marijuana-impaired drivers often show their medical marijuana cards to police officers who pull them over, as though the card legally entitles them to drive under the influence of drugs -- which it does not.
The U.S. Department of Transportation found that although the harm of marijuana for drivers is minimal compared with that of alcohol and other drugs, it may be dangerous in certain situations, such as when quick thinking is required or when a driver has combined marijuana with alcohol or other drugs.
No one is advocating that driving while stoned is better than being alcohol- or drug-free, but experts agree that marijuana use while driving presents far less danger than many other drugs as well as alcohol.
Meanwhile, more Americans appear to be embracing marijuana. A Gallup poll released in October 2011 found that a record-high 50 percent of Americans favor legalizing marijuana. In 2009, the National Survey on Drug Use and Health showed 16.7 million Americans age 12 and older had smoked pot at least once in the month before being surveyed.
Could widespread legalization boost road safety?
While the University of Colorado-Denver study presents striking evidence of marijuana’s effect on road safety, the research was limited to motorists who have access to medical marijuana. In some states, that’s a relatively significant portion of the population. In Montana, 3 percent of the state’s population has access to medical marijuana; in Colorado, it's 2.5 percent. Actual percentages for marijuana use may be considerably higher than that, however.
“Under medical marijuana laws, caregivers and patients can grow marijuana, and there’s very little policing of this,” Rees says.
Rees believes that authorized marijuana users often sell or give pot to others for recreational use. He says many of those recreational users probably are young adults -- a group who's responsible for a disproportionately high number of alcohol-related car crashes. Marijuana advocacy group NORML says pot is the third most popular recreational "drug" in the United States, behind alcohol and tobacco.
Rees teamed up with D. Mark Anderson, assistant professor of economics at Montana State University, on the marijuana study.
For now, medical marijuana is legal in Alaska, Arizona, California, Colorado, Delaware, Hawaii, Maine, Michigan, Montana, Nevada, New Jersey, New Mexico, Oregon, Rhode Island, Vermont and Washington, as well as the District of Columbia. In those places, doctors prescribe marijuana to ease pain and suffering for patients with conditions like cancer.
Federal law prohibits the growth and sale of marijuana for any purpose. Opponents of legalizing the drug maintain that marijuana is a "gateway" to harder drugs like cocaine and heroin, and argue that the dangers posed by stoned drivers would rise.
While widespread legalization of marijuana isn’t likely in the near future, such a move might have a dramatic effect on road safety if drivers -- particularly young adults -- flock to marijuana instead of alcohol to get buzzed.
“When you see fewer traffic accidents in every state that legalizes medical marijuana, that’s strong proof,” Rees says.