FILE - In this April 20, 2018 file photo, an attendee celebrates at 4:20 p.m. by lighting up marijuana during the Mile High 420 Festival in Denver. New research has found some Colorado teenagers who use marijuana are shifting away from smoking it in favor of edible products. About 78% of the Colorado high school students who reported consuming marijuana in 2017 said smoking was their usual method, down from 87% two years earlier. The number of teens who usually consumed edible marijuana products climbed to about 10% from 2% in the same two-year span while the number of users dabbing increased to about 7.5% from 4%. (AP Photo/David Zalubowski, File)

DENVER | A survey of Colorado residents who use cannabis daily found many believe driving under the influence of the substance is safe.

The Colorado Department of Transportation conducted the survey of 18,000 residents from 2017 to 2019, The Denver Post reported Wednesday.

The department hopes to use perceptions to build a public awareness campaign about the dangers of driving under the influence of marijuana.

The agency said 13.5% of drivers involved in fatal crashes in 2018 tested positive for cannabis.

The Denver Post conducted an independent analysis in 2017 of state and federal data that found the number of drivers involved in fatal crashes in Colorado who tested positive for marijuana more than doubled since 2013.

The transportation department survey made general conclusions about the attitudes of respondents toward driving under the influence.

The more often survey respondents used cannabis, the less danger they perceived in driving under the influence, while some said cannabis helped them drive better.

Cannabis users were skeptical of related laws, policies and enforcement and many did not find available statistics convincing enough to change their behavior.

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