Keeping the roads safe is one of the biggest concerns faced by law enforcers in states that have or plan to legalize recreational marijuana use. That challenge is especially daunting given public attitudes toward driving under the influence of marijuana. According to the Civilized Cannabis Culture Poll, the majority of Americans think that marijuana impairs driving, but a surprising number believe that cannabis has no effect on or even increases their ability to drive.

The poll of 1,050 Americans (370 cannabis consumers) conducted by Environics Research Group found that 61 percent of consumers believed that cannabis use impairs driving. But approximately one in four cannabis users (24 percent) think it actually increases their ability to drive. And 37 percent of people who have been using cannabis for over 10 years believed it had no effect on their performance behind the wheel.

Peter Stroup, founder of the marijuana advocacy group NORML and a current board member, says these numbers reflect the confidence many cannabis consumers seem to have about getting behind the wheel. He says people need to understand it's not acceptable, no matter how confident they feel in their abilities. "We need to meet the standard of the general population," he says. "People who are impaired should be prosecuted."

The science says it does affect driving capabilities

The precise affect that marijuana has on drivers is still being studied. But current research has been substantial enough for the National Institute on Drug Abuse to confidently post the following statement on their website:

"Marijuana significantly impairs judgment, motor coordination, and reaction time, and studies have found a direct relationship between blood THC concentration and impaired driving ability," the National Institute on Drug Abuse claims.


NIDA based that conclusion on a curation of studies conducted over the last five years by American and European researchers, who found compelling evidence that cannabis decreases a person's driving ability, increasing their likelihood of getting into non-lethal and fatal accidents compared to sober drivers in test studies.

So why do so many people think it's safe? It might have something to do with recent research that suggests driving high isn't as dangerous as driving drunk. But that doesn't mean driving high is safe. In any case, Tom Angell, a longtime advocate and Marijuana Majority founder, says it's not a helpful conversation to have when people fear the possibility of people driving while high.

"There is some scientific data showing that cannabis doesn't impair driving as much as alcohol," he told Civilized. "But for me, personally, as a frontline advocate trying to push legalization forward, I don't think it's a helpful thing to highlight and argue, because many people fear that it will put more impaired drivers on the road. So I don't think that's a particularly helpful debate to have in society."

The need to develop the right road test

The lack of an effective cannabis breathalyzer is impairing efforts to keep high drivers off the road. A breathalyzer prototype developed by Cannabix Technologies (in association with researchers from the University of Florida) is doing well in the product testing phase. But it isn't ready for use by traffic cops yet.

Meanwhile, researchers are struggling to determine what exactly the legal limit for cannabis should be, and how quickly the THC concentration in a person's bloodstream dissipates. The THC in an impaired driver's system might decrease significantly by the time police can administer a blood test, which means that they don't know exactly how high a driver was when pulled over.

Prohibition is another roadblock in the way of keeping roads safe, according to UC San Diego researchers who are teaming up with the California state for a landmark study that could develop a better roadside sobriety test using tablets like iPads. Researchers told the San Diego Union Tribune that "it can take as long as 18 months to obtain federally sanctioned marijuana for research" due to restrictions on access to cannabis.

So should we hold off on marijuana legalization until we have the right equipment to curb high drivers? That would only work if prohibition kept people from using marijuana, which it hasn't. But legalization could arm law enforcers with other weapons to keep the roads safe: time and resources.

Angell told Civilized that when he meets people who oppose legalization because they're worried about road safety, "I say police won't have to spend as much time and resources chasing down people for possessing and buying marijuana, so they'll have more resources to keeping inebriated drivers off the road."

Education and moral standards are best defenses right now

Until we have devices that help screen for high drivers, the best way to combat misperceptions about road safety is through educating the public and encouraging cannabis consumers to hold themselves to high standards.

Education was a prominent message that stakeholders in the legal states of Colorado and Washington stressed in a report published in 2015 by the Canadian Centre on Substance Abuse (CCSA). Strong communications campaigns could help inform the public about the potential dangerous and legal ramifications of driving under the influence of drugs (DUID).

Until we know what safe limits should be, drivers should err on the side of caution and follow guidelines offered by the National Organization for the Reform of Marijuana Laws. NORML's "Principles of Responsible Cannabis Use" state, "Although cannabis is said by most experts to be safer than alcohol and many prescription drugs with motorists, responsible cannabis consumers never operate motor vehicles in an impaired condition."

Angell, and other advocates like him, is firm in his position: people need to feel confident that, as more states legalize, their roads remain free of impaired drivers.

"They shouldn't do it. I don't recommend it. And I support the continued criminalization of that sort of behaviour. To me, that's not what marijuana legalization is about. I have a family and I want them to be safe on the road."

Our Poll 2016 Page has more original stories from the Civilized Cannabis Culture Poll.

h/t TIME