The majority of American drivers don’t consider marijuana as serious a threat to road safety as alcohol, according to a survey by the Insurance Institute for Highway Safety. But drivers living in states where recreational marijuana use is legal are more likely to view the drug as a highway safety problem than drivers in other states.

IIHS conducted the phone survey last year between July and October. The results were published in the organization’s most recent newsletter.

In states where recreational use of marijuana is legal, 43% of motorists said that driving after consuming marijuana is a problem in their community. In contrast, 28% of motorists in states where recreational use is banned viewed the drug as a driving safety problem locally.

On a national scale, 80% of drivers favored legalizing marijuana for medical use. But just 42% supported legal recreational use by adults 21 years of age and older. Under federal law, marijuana is still a Schedule 1 controlled substance.

Drivers who supported the legalization of recreational use were much less likely to view the drug as a driving safety problem than drivers who opposed such legalization, the survey also found. Drivers in marijuana-legal states were twice as likely to say they had used the drug within the past year.

“The message that alcohol and driving is a dangerous combination is well-entrenched, but marijuana isn’t viewed quite as negatively,” said Angela Eichelberger, a senior research scientist for IIHS and the study’s author. “As more states legalize marijuana use, we anticipate that perceptions about the drug’s effects on driving may shift.”

In November, voters in California, Maine, Massachusetts, and Nevada approved recreational use of marijuana, and medicinal use passed in Arkansas, Florida, and North Dakota. Eight states and Washington D.C. have legalized marijuana for all uses, while 20 states have implemented comprehensive medical marijuana programs. Sixteen more states allow limited access to marijuana products, usually extracts.