Planning to celebrate 420 in Colorado? Here's how to know when you've had too much to drive

Miles Blumhardt, Fort Collins Coloradoan
·3 min read

In Colorado, 4/20 is to marijuana users as New Year's Eve is to alcohol drinkers.

The events lead to heavy consumption of drugs and/or alcohol. So, law enforcement increase patrols, leading to an increase in driving under the influence citations and impaired-driving deaths.

In 2022, the last year for which numbers were reported, there were 101 traffic deaths in Colorado involving cannabis above the legal limit, according to the Colorado Department of Transportation.

That's why the agency has a warning for drivers on April 20: "Drive High, Get a DUI."

4/20 is marked with an assortment of cannabis-inspired popular events such as 420 on the Rocks and The Mile High 420 Festival.

Whether attending one of those or other public cannabis events or privately celebrating the 10-year anniversary of recreational marijuana becoming legal in Colorado, here are tips to make sure everyone gets home safely:

US 287, known as the 'Highway of Death,' will see added patrols

The 30-mile stretch of U.S. Highway 287 from Colorado Highway 14 north of Fort Collins to the Wyoming state line is one of the more dangerous sections of highways in Colorado, earning it the name "Highway of Death" due to its number of fatalities.

Among the leading causes of those fatal crashes is driving under the influence, according to Colorado State Patrol.

That stretch connects Colorado State University in Fort Collins, where recreational marijuana use is legal, and the University of Wyoming in Laramie, where it is not legal.

Law enforcement agencies will add extra patrols to the highway April 20 to watch for reckless and impaired driving in Larimer County, according to a state patrol news release.

The state patrol is asking the public to report motorists driving recklessly or who might be impaired by calling *277.

This is part of Colorado's statewide impaired-driving enforcement campaign that runs through April 24.

More: A timeline of marijuana laws in Colorado, Fort Collins

Guidelines to know if you are over the legal limit for cannabis in Colorado

Experience levels and consumption methods of cannabis will impact your impairment, but here are general guidelines, according to the Colorado Department of Transportation:

  • Wait at least six hours after smoking cannabis containing less than 35 mg of THC before driving. Wait longer if you have smoked more than 35 mg.

  • Wait at least eight hours after eating or drinking cannabis containing less than 18 mg of THC before driving. Wait longer if you have eaten/drank more than 18 mg.

  • If you’re mixing cannabis with alcohol, you need to wait even longer.

  • Given the length of time before you're possibly no longer impaired, plan ahead for a sober ride home through various safe alternatives.

Mixing cannabis and alcohol only makes driving worse

Mixing cannabis and alcohol enhances the impairment effects of both, according to the Colorado Department of Transportation:

  • Research shows that users are more likely to drive after using cannabis and alcohol than after consuming marijuana alone.

  • You can get a DUI even if you are under the legal limit of both alcohol and cannabis.

  • A July 2023 report by the Colorado Division of Criminal Justice analyzed 2020 data from more than 21,000 impaired-driving cases filed in Colorado. It found 75% of people with Delta-9 THC detected in their system also had some other substance present. Alcohol and cannabis were the most common.

  • In 2022, 29% of the fatal crashes that tested for more than one drug tested positive for multiple impairing substances.

This article originally appeared on Fort Collins Coloradoan: 420 in Colorado: How to know when you've had too much pot to drive