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Insurance Industry Report On Marijuana, Driving Finds 'Rocky Road So Far'

Cop speaks to media
Don Thompson
Highway Patrol Lt. Eric Jones speaks after a news conference in Sacramento, Calif., in 2017 before California legalized sales of recreational marijuana.

Lawmakers are facing all sorts of thorny issues as they consider legalizing recreational marijuana. Near the top of the list: Will it lead to more impaired drivers?

The answer is important not just to policymakers and law enforcement. The insurance industry is watching the issue unfold in the 10 states that have already legalized marijuana. Its findings to date were published last month in a new report, authored by the Insurance Information Institute (III).

Colorado, Oregon, and Washington state all saw increased collision claim frequencies (a 6 percent increase, on average) that correlated with recreational marijuana legalization, according to Highway Loss Data Institute data cited in the III report. Colorado’s claim frequencies jumped 12 to 13 percent; the increase was less pronounced in Oregon and Washington state. 

“It’s a complicated story,” said Lucian McMahon, senior research specialist at III who co-authored the March study. “It’s safe to say that there is a probably an impact on at least collision frequencies in states with legal recreational marijuana, all things being equal.”

McMahon cautions that the research is far from definitive on legalized marijuana’s impact on traffic safety. Data from states that have legalized is too young and not yet robust enough, he said. And there needs to be more research on “concurrent other drug use,” like when someone mixes alcohol and marijuana.

Yes, stoned driving—which impairs motor skills and situational awareness—is dangerous, he said.

“The extent to which it’s dangerous—and whether it’s actually impacting traffic safety and how public policy should react—these are all complicated issues,” McMahon said on GLT’s Sound Ideas.

A big reason is the drug itself. The presence of THC—the chemical in marijuana that causes intoxication—in someone’s body does not necessarily indicate impairment, McMahon said. With alcohol, someone’s blood-alcohol level and impairment are closely linked over time, he said. But with marijuana, he said, measurable THC levels could fall off a cliff and a person could still be impaired later.

Marijuana is legal in 10 states and the District of Columbia. So far, states have taken a “scattershot approach” to impaired-driving enforcement, McMahon said. Some just pick a number—like anyone with 2 to 5 or more nanograms of THC in their blood can be convicted of driving under the influence. Colorado, by contrast, uses a hybrid approach called the “permissible inference standard,” where 5+ nanograms of THC can get you arrested and prosecuted, but behavioral reports or other factors would be needed to convict, McMahon said.

“There is currently no scientifically sound roadside test for marijuana impairment,” he said.

There are also implications for auto insurers. State Farm is the largest auto insurer in the U.S., with around 18 percent of market share as of 2017, according to the III.

Auto insurance rates may be affected by the spread of marijuana legalization, especially if it is associated with an increased in impaired driving and related accidents, the III study found. Those convicted of driving under the influence of marijuana may see their rates rise.

“From a personal auto standpoint, it’s something to keep an eye on,” McMahon said.

The III is funded in part by insurance companies themselves, including Bloomington-based State Farm.

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Ryan Denham is the content director for WGLT and WCBU.