As the push to legalize marijuana gains momentum, so is evidence that more permissive policies on the drug are putting motorists at risk.
The Insurance Institute for Highway Safety found, in a study released Thursday, that traffic accidents are rising in states that have legalized recreational marijuana. That followed stark warnings from the National Transportation Safety Board, which on Tuesday issued several recommendations to combat drug-impaired driving.
“The last thing in the world that we want is to introduce another legal substance where we may be adding to that toll and to the carnage on our highways,” said David Harkey, president of the Insurance Institute. “With marijuana impairment, we’re just now starting to understand what we don’t know.”
After retail sales of recreational cannabis began, the frequency of collision insurance claims in Colorado, Nevada, Oregon and Washington State rose about 6 percent higher than in nearby states where marijuana is still illegal, the IIHS said in the study.
A separate IIHS study saw a 5 percent increase in the rate of crashes per million vehicle registrations reported to police in Colorado, Oregon and Washington vs. neighbors that haven’t legalized the drug.
“The bottom line of all of this is that we’re seeing a consistently higher crash risk in those states that have legalized marijuana for recreational purposes,” Harkey said.
Recreational cannabis is also legal in California, Alaska, Maine, Massachusetts and Vermont while 22 other states have legalized the drug for medical purposes, according to the IIHS, which is financed by insurers. Harkey said policymakers should take heed of the findings as more states are set to consider ballot referendums or legislation to expand legal use of the drug.
Combating drug-impaired driving presents many challenges. Experts say more research is needed to better understand marijuana impairment. Motorists sometimes mix different drugs, or drugs with alcohol, making it harder to isolate their effects.
The NTSB’s recommendations followed an investigation of a 2017 crash in rural Texas that killed 13 people. The accident was caused by a pickup truck driver who was high on marijuana and an anti-anxiety medication and slammed head-on into a church bus. Video shot by another driver showed the pickup repeatedly veering onto the shoulder and across the double-yellow line for 15 minutes.
“The rising tide of drug-impaired driving did not begin with this driver, and it will not end with him,” Robert Sumwalt, chairman of the NTSB said Tuesday. “Law enforcement needs additional tools and advanced training to detect impaired drivers before they crash, regardless of the impairing drug they’re using.”
Drugs were detected in 30 percent of drivers who died in accidents in 2006 and were tested for drugs, according to the NTSB. That number jumped to 46 percent in 2015. In random roadside testing, more than 22 percent of drivers showed evidence of drug use, according to National Highway Traffic Safety Administration data.
Among the NTSB’s recommendations was one that called for the traffic safety administration to develop specifications for “oral fluid” screening devices that law enforcement can use to test drivers for drug impairment during roadside stops.
Now, there is no widely accepted means of testing that can be used in the way that police officers are quickly able to determine alcohol levels in motorists.
The NHTSA convened public meetings in Seattle, Baltimore and Nashville on drug-impaired driving this year and began addressing the issue in its long-running drunken driving ad campaigns for the first time.
A recent report by traffic safety officials in Washington State found a sharp rise in the mixing of drugs and alcohol since the state legalized recreational use of marijuana in 2014. The Washington Traffic Safety Commission found that one in four traffic fatalities in 2016 involved drivers who mixed drugs with alcohol or combined drugs.
Marijuana and alcohol was the most common combination, said Shelly Baldwin, the commission’s legislative director.
The body of available research on marijuana’s impairing effects is much more limited than studies of alcohol impairment, and much of it likely obscures the risks, Baldwin said. For example, past studies have examined driver impairment using far less potent strains of the drug than what is actually available to consumers at retail marijuana dispensaries, she said.
“We need a lot more research,” she added. “We need it on the types of marijuana that people are actually using and we needed it 10 years ago, unfortunately.”
Bloomberg’s Alan Levin contributed to this report.