Southern Traveler
h Home h Features h Departments h Web Bonus h Media Info h Reader Resources h Archives h space

Solving the Cannabis Conundrum

AAA Foundation research will help to bridge the knowledge gap
on marijuana-impaired driving.

As the legalization of marijuana increases across the United States, the lack of knowledge and research about its effects on drivers is becoming more glaring. AAA is one of the leading organizations helping to fill that gap.

“When it comes to cannabis and driving, public policy is way ahead of the research and data, which is counterproductive,” said AAA Traffic Safety Advocacy & Research Director Jacob Nelson.

Pot’s popularization

The recreational use of marijuana for adults is now legal in four states--a number that doubled late last year, when voters in Alaska and Oregon joined Colorado and Washington in approving ballot measures --and 19 additional states plus the District of Columbia have authorized marijuana for medicinal purposes.

According to Dr. Barry Logan, vice president of Forensic Science Initiatives and Chief of Forensic Toxicology at NMS Labs and an internationally recognized expert in alcohol, other drugs and traffic safety, marijuana is the most popular recreational drug in the U.S. after alcohol and tobacco. In 2013, he said, an estimated 25 million Americans smoked cannabis, and more than 14 million do so regularly. Tetrahydrocannabinol, or THC, the active ingredient in marijuana, is the second most common substance, after alcohol, found in the blood of impaired and fatally injured drivers.

The most recent roadside survey by the National Highway Traffic Safety Administration (NHTSB) showed that 8.65 percent had marijuana in their systems on weekend evenings. Several other studies have shown that up to 14 percent of drivers who sustained injuries or died in traffic crashes tested positive for THC.

With increased legalization efforts, those numbers could rise in future years.

Logan said past studies support the belief that marijuana smokers have an increased crash risk within two hours of smoking. And according to the National Institute on Drug Abuse, marijuana negatively affects drivers’ attentiveness and perception of time and speed.

“There’s a lot of focus on marijuana from the legal side,” said National Transportation Safety Board member Mark Rosekind. “What’s not being discussed is the safety side of it. Marijuana can be just as impairing. I think most people, whether they smoke marijuana or not, would say they don’t want to be driving next to somebody who’s impaired by marijuana.”

National standard?

Indeed, AAA’s 2013 Traffic Safety Culture Index showed that 80.3 percent of drivers support having a marijuana per se law, which makes it illegal to drive with a certain amount of marijuana in one’s system. However, lack of data has prevented a consensus on what such a standard should be.

Even though marijuana is now legal in some form in nearly half the states, there is no standardized roadside test--such as a breathalyzer for alcohol--that measures THC levels in a driver’s system. Similarly, no nationwide legal standard--such as a .08 percent blood alcohol concentration--constitutes driver impairment in regards to marijuana.

The AAA Foundation for Traffic Safety is sponsoring two studies that began last year to determine, among other things, whether the incidence of marijuana-impaired driving in Washington State has increased since legalization, the relationship between the blood concentration of THC and crash severity, and a threshold of active THC blood concentrations at which driver impairment and crash risk increase significantly. The results of both studies are expected to be released by early 2016.

Kevin Adams is a freelance writer based in Orlando, Fla., and writes for multiple AAA publications.

By The Numbers

March/April 2015 Issue

Coming in the May/June issue

Get the perspective from law enforcement on drugged driving as our series continues. Hear about the tools they have and the challenges they face roadside and in court.

^ to top | previous page