Study Finds Car Insurance Premiums Dropped In Legal Medical Marijuana States By At Least $22 Per Driver

A University of Iowa study found that car insurance premiums dropped in states after they legalized medical marijuana, suggesting that driving while high may not be as dangerous as driving drunk. 

Cameron Ellis, professor of finance at the University of Iowa (U of I) said they studied insurance data at the ZIP code level and found states that made medical marijuana legal between 2014 and 2019 saw premiums drop by an average of $22 per driver in the first year.

“In areas that had high levels of DUIs prior to medical cannabis legalization, rates fell at a much higher rate,” Ellis said, “because as bad as marijuana is for driving, alcohol is much worse, and so it’s sort of this reduction in DUIs that’s leading to the decline.”

There are likely two explanations for this, Ellis said, the first being that some of those people who'd been arrested for drunk driving simply changed their recreational substance of choice from alcohol to weed and that cannabis and alcohol impair drivers in different ways.

“But another potential one is that when you consume alcohol and marijuana together, you tend to do it at home,” Ellis told local media. “You don’t go smoke in a bar, you do it at home and so you’re just literally driving less while drinking, even if you’re not drinking less.”

Legalization Opponents Say All Impairment Is Dangerous

Opponents of legalizing marijuana point to the harm already caused by people who drive under the influence of alcohol and argue legalizing another mind-altering substance will only lead to more crashes, injuries and deaths. 

Ellis argues that the U-I study essentially debunks that idea, as alcohol and cannabis affect drivers in different ways.

“There’s this trope of someone’s like, ‘Oh, I’m a better driver while I’m drunk,’ but, no you’re not, but you’re really, really confident and that causes a lot of problems,” he said, “whereas [with] marijuana famously, you’re paranoid that there are cops everywhere, ‘I don’t want to get caught, I’m going to go exactly the speed limit.’”

On the other hand, alcohol tends to make drivers more aggressive, while marijuana has a mellowing effect and makes drivers more aware of their inabilities, Ellis says, so they drive slower and take fewer risks.

The report found about $820 million has been saved so far in crash-related health expenditures as a result of marijuana legalization. Ellis said that if medical marijuana was legalized nationally, another $320 million could be saved.

The study was published in the journal Health Economics.