Agents Amanda Toma and Ashley Brodeur work with customers outside in the parking lot of cannabis purveyor Berkshire Roots in Pittsfield, Mass. Laws legalizing recreational marijuana may lead to more traffic deaths, two new studies suggest, although questions remain about how they might influence driving habits. Previous research has had mixed results and the new studies, published Monday, June 22, 2020, in JAMA Internal Medicine, can’t prove that the traffic death increases they found were caused by marijuana use. (Gillian Jones/The Berkshire Eagle via AP, File)

Agents Amanda Toma and Ashley Brodeur work with customers outside in the parking lot of cannabis purveyor Berkshire Roots in Pittsfield, Mass. Laws legalizing recreational marijuana may lead to more traffic deaths, two new studies suggest, although questions remain about how they might influence driving habits. Previous research has had mixed results and the new studies, published Monday, June 22, 2020, in JAMA Internal Medicine, can’t prove that the traffic death increases they found were caused by marijuana use. (Gillian Jones/The Berkshire Eagle via AP, File)

Recreational pot laws may boost traffic deaths, studies say

One study found an excess 75 traffic deaths per year after retail sales began in Colorado.

By LINDSEY TANNER

AP Medical Writer

Laws legalizing recreational marijuana may lead to more traffic deaths, two new studies suggest, although questions remain about how they might influence driving habits.

Previous research has had mixed results and the new studies, published Monday in JAMA Internal Medicine, can’t prove that the traffic death increases they found were caused by marijuana use.

One study found an excess 75 traffic deaths per year after retail sales began in Colorado in January 2014, compared with states without similar laws. But it found no similar change in Washington state.

The other study looked at those states plus two others that allow recreational pot sales, Oregon and Alaska. If every state legalized recreational marijuana sales, an extra 6,800 people would die each year in traffic accidents, the researchers calculated. They found an increase of 2 deaths per billion miles traveled compared with 20 states without those laws. That change was slightly higher than in the other study.

Both involved several years of traffic death data from the National Highway Traffic Safety Administration before and at least two years after retail sales of recreational pot began in the states examined. Those sales dates ranged from 2014 to 2016.

The studies lack information on whether motorists were stoned when they crashed. Marijuana can remain in tissues for several days so even if toxicology tests detected it after a fatal crash, that wouldn’t prove the driver was impaired, said co-author Magdalena Cerda, a New York University researcher.

It’s possible that recreational pot laws might affect drivers’ use of other drugs, including alcohol, she noted.

“That’s an open question we need to answer in further research,” Cerda said.

A journal editorial said more rigorous research is needed including studies on how often motorists use drugs.

“Clearly, introducing new legal intoxicants has the potential to … lead to deaths due to impaired driving,” the editorial said.

Recreational marijuana is legal in 11 states.

Variations in sales taxes, purchase limits and other aspects of marijuana laws in each state could play a role in any impact on traffic deaths. Also, when the two-state study was done, pot stores were more densely located in Colorado than in Washington, which could have made the drug more readily available, the authors said.

The four-state study, led by Dr. Russell Kamer of New York Medical College, accounted for jobless rates, maximum speed laws and seat-belt laws. But the authors said other factors they did not consider could have influenced traffic deaths.

More in News

This 2020 electron microscope image provided by the National Institute of Allergy and Infectious Diseases - Rocky Mountain Laboratories shows SARS-CoV-2 virus particles which causes COVID-19, isolated from a patient in the U.S., emerging from the surface of cells cultured in a lab. On Monday, Oct. 5, 2020, the top U.S. public health agency said that coronavirus can spread greater distances through the air than 6 feet, particularly in poorly ventilated and enclosed spaces. But agency officials continued to say such spread is uncommon, and current social distancing guidelines still make sense. (NIAID-RML via AP)
COVID at a glance for Monday, Jan. 25

The most recent state and local numbers.

This October 2020 photo shows the illuminated Kennicott at the Auke Bay Ferry Terminal. Alaska Department of Transportation and Public Facilities is now accepting comments on the proposed Alaska Marine Highway summer ferry schedule. (Ben Hohenstatt / Juneau Empire File)
Public comment period opens for ferry schedule

A teleconference is set for Feb. 8.

Juneau-Douglas High School Yadaa.at Kalé senior Cooper Kriegmont shoots during a basketball game against Ketchikan on Friday,  Jan. 22, 2021. Kriegmont scored his 1,000th point during the two-game series. (Courtesy photo / Lexie Razor)
Good to be back: Short run up leads to mixed results against Ketchikan

“It doesn’t matter what the outcomes were,.”

Cars zoom down the track at Saturday's Pinewood Derby. The COVID-19 pandemic forced the race to move a virtual format. (Dana Zigmund/Juneau Empire)
The race must go on

Cub Scouts take the Pinewood Derby high tech.

Has it always been a police car? (Michael Penn / Juneau Empire)
Police calls for Tuesday, Jan. 26, 2021

This report contains public information from law enforcement and public safety agencies.

In this July 13, 2007, file photo, workers with the Pebble Mine project test drill in the Bristol Bay region of Alaska, near the village of Iliamma. (AP Photo / Al Grillo)
Pebble developer files appeal with Army Corps

The Army Corps of Engineers rejected Pebble Limited Partnership’s application in November.

This August 2019 photos shows a redline at Treadwell Arena designed by Tsimshian artist Abel Ryan. The arena is adding new weekly events to its schedule, City and Borough of Juneau announced. (Michael Penn / Juneau Empire File)
Treadwell Arena adds new weekly events

Hockey and open skate are on the schedule.

This 2020 electron microscope image provided by the National Institute of Allergy and Infectious Diseases - Rocky Mountain Laboratories shows SARS-CoV-2 virus particles which causes COVID-19, isolated from a patient in the U.S., emerging from the surface of cells cultured in a lab. On Monday, Oct. 5, 2020, the top U.S. public health agency said that coronavirus can spread greater distances through the air than 6 feet, particularly in poorly ventilated and enclosed spaces. But agency officials continued to say such spread is uncommon, and current social distancing guidelines still make sense. (NIAID-RML via AP)
COVID at a glance for Friday, Jan. 22

The most recent state and local numbers.

A Coast Guard Station Juneau 45-foot Response Boat-Medium patrols Auke Bay during an exercise in 2018. A response boat similar to the one in the photo was struck by a laser near Ketchikan on Saturday, Jan. 17, prompting an investigation into the crime. (Lt. Brian Dykens / U.S. Coast Guard)
Coast Guard wants information after laser pointed at boat

“Laser strikes jeopardize the safety of our boat crews…”

Most Read