Many Coloradans who use cannabis daily believe it is safe to drive under the influence and say they would like to see empirical evidence that proves otherwise before changing their behavior.

That’s according to the results of a survey of 18,000 residents conducted by the Colorado Department of Transportation from 2017 to 2019. CDOT aimed to gauge the perception of driving under the influence of cannabis in hopes of building a campaign to reduce the number of traffic crashes and fatalities involving the substance.

In 2018, 13.5% of drivers involved in fatal crashes tested positive for cannabis, according to the agency. In 2017, The Denver Post independently analyzed state and federal data and found the number of drivers involved in fatal crashes in Colorado who tested positive for marijuana rose sharply each year since 2013, more than doubling in that time.

Though CDOT’s survey didn’t offer specific statistics, it made general conclusions about attitudes toward driving and marijuana. For example, the more often survey respondents used cannabis, the less dangerous they tended to believe driving after using it was.

Some said it even helped them drive better, the report said.

Cannabis users also said they are skeptical of laws, policies and enforcement regarding driving impaired, CDOT found. Many respondents didn’t find statistics currently available on the subject to be convincing enough to change their ways. Some dismissed existing research and data as counter to their own experiences.

Cannabis users told CDOT they wanted more information that was “credible, nuanced, and empirical that could prove the dangers of driving after using cannabis,” the report said.

CDOT plans to use this information to develop a public awareness campaign about the dangers of driving under the influence of marijuana.

View the full report, entitled The Cannabis Conversation.