Does recreational marijuana make roads less safe? What to know ahead of Ohio Issue 2 vote

Critics of recreational marijuana often sound the alarm about people driving while high.

Now, the debate is heating up in Ohio.

Voters will decide Nov. 7 whether to support Issue 2, which would legalize marijuana for adults 21 and older and establish rules for buying, selling and growing cannabis. Proponents say regulation would put the illicit market out of business and bring millions of dollars in tax revenue to Ohio, instead of letting Michigan reap the fiscal benefits.

Live event: How to go and get your questions answered at marijuana issue forum near Columbus

But Gov. Mike DeWine and other GOP leaders contend it will have an adverse effect on the state's culture and make people more willing to drive under the influence of marijuana.

Here's what voters need to know about the proposal, marijuana OVIs and more.

What does Issue 2 say about driving with marijuana?

The proposed statute bars people from driving a car, bike, boat or airplane while impaired by marijuana. Passengers would be prohibited from smoking or vaping in the vehicle. The state's current OVI laws would apply to anyone who violates those rules.

To request a field sobriety test, police must have "an independent, factual basis giving reasonable suspicion" that the person is driving under the influence or has too much marijuana in their system. The legal use of adult cannabis alone would not be enough to justify a sobriety test or to suspend someone's license.

How many marijuana OVIs is Ohio seeing now?

The number of OVI arrests involving marijuana have decreased in recent years, according to Ohio State Highway Patrol data, mirroring an overall decline in OVIs. Ohio saw 622 marijuana-only OVI arrests last year and another 647 involving marijuana and other drugs, compared to 1,387 and 999 in 2019.

Ohio legalized medical marijuana in 2016.

Lt. Nathan Dennis said marijuana is present more often in fatal crashes related to OVIs. The number of drug-induced crashes increased 41% from 2019 to last year, while crashes involving alcohol and drugs jumped 20%. The state patrol data do not specify what kind of drugs were found in those cases.

"If people are going to partake in alcohol or drugs and drive, what they need to think about is how long that chemical is affecting their ability to drive," Dennis said.

Using 2022 crash statistics and research from the Insurance Institute for Highway Safety, law enforcement groups opposing Issue 2 projected fatal accidents in Ohio would increase by 48 and injury crashes by 2,298 if the measure passes. Those are 4.1% and 5.8% increases, respectively.

What happened in other states?

Researchers have conducted studies to assess the effect of marijuana on road safety. A recent review of existing literature identified more studies that pointed to negative consequences, such as an uptick in accidents and the number of drivers testing positive for THC.

At the same time, several other papers did not point to an increase in accidents or hospital visits. One study challenged the causal effect of marijuana on traffic fatalities and determined control states saw similar trends as Colorado and Washington.

Researchers tend to look at those two states because they were the first in the nation to legalize adult-use marijuana. Washington saw more fatal crashes involving THC-positive drivers after the market launched in 2014, but the numbers have largely remained stable aside from a peak in 2020, according to the Washington Traffic Safety Commission. In 2021, over 80% of drivers who tested positive for THC also had alcohol or other drugs in their system.

Colorado has seen an increase in marijuana-related DUIs, and more than half of the citations in 2020 included alcohol, as well. That same year, 20% of drivers and 24% of operators (which includes pedestrians, bicyclists and passengers) involved in traffic deaths tested positive for THC.

Does marijuana testing prove impairment?

Proponents of Issue 2 and other experts say statistics don't tell the full story. For starters, they argue, correlation does not equal causation, and states that legalize marijuana tend to test for it more frequently.

“It’s very hard to capture real precise data here," said Doug Berman, executive director of the Drug Enforcement and Policy Center at Ohio State University. "If it was a no-brainer that legalization made the roads a lot more dangerous, we would know that, and that’s not what the evidence shows."

Since marijuana stays in the body longer than alcohol, testing positive doesn't necessarily mean impairment. The drug's effects − and how long it sticks around − also depend on metabolism, frequency of use and other factors. In regular users, such as medical cannabis patients, urine tests pick up marijuana up to 30 days after consumption.

Michigan piloted a roadside saliva test for marijuana, but other states − including Ohio − largely rely on blood or urine tests. Those happen after police make an arrest, though. Before that, Dennis said, state troopers look for signs of impairment on the road and conduct field sobriety tests. They won't know for sure until later which drugs, or how much of them, are in a person's system.

Tom Haren, a spokesman for the Coalition to Regulate Marijuana Like Alcohol, said the proposed law will still penalize people for driving while high. It also provides tax revenue to municipalities with dispensaries, which Haren said they could use to train local police as drug recognition experts.

“It gets back to regulating marijuana just like alcohol," Haren said. "Drivers don’t get pulled over because they have consumed alcohol at some point in their life. You get an OVI based on being impaired."

Haley BeMiller is a reporter for the USA TODAY Network Ohio Bureau, which serves the Columbus Dispatch, Cincinnati Enquirer, Akron Beacon Journal and 18 other affiliated news organizations across Ohio.

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This article originally appeared on The Columbus Dispatch: Ohio Issue 2: Can recreational marijuana affect traffic safety?