Vehicles can ignite wildfires through sparks from dragging chains, hot exhaust systems or flat tires, particularly when parked or driven over dry grass and pine duff instead of hard surfaces.

The 2020 Grizzly Creek fire in Glenwood Canyon demonstrated the risk. The human-caused blaze, likely sparked by interstate traffic including possible trailer chains, burned 32,631 acres and forced major closures along Interstate 70.

The American Automobile Association urged drivers to treat vehicles as potential fire starters or preventers during a dangerous stretch of the fire season in a June 17 release.

“On a red-flag day, dry grass doesn’t need a campfire or a downed line to catch and spread. All it takes is a single spark, including from a car,” said Skyler McKinley, AAA regional director of public affairs.

More than 90% of Colorado wildfires trace to human causes, while lightning accounts for only about 7% of fires, according to the Colorado Division of Fire Prevention and Control.

The National Interagency Fire Center tracks vehicles as a distinct ignition source. Common triggers include dragging trailer chains or metal parts that scrape pavement, driving on flat tires or exposed rims, hot catalytic converters igniting dry vegetation and worn brakes.

Recent spot fires in the Glenwood Canyon area follow similar patterns officials attributed to interstate traffic.

The association said drivers should secure tow chains in an X pattern under the hitch, inspect undercarriages for hanging parts, properly inflate tires, avoid parking or driving over dry grass and pine duff, and maintain brakes and exhaust systems.

The organization also recommended carrying a fire extinguisher and postponing nonessential towing on high-risk days.

Motorists who spot a new fire should call 911 with the most precise location possible. Guidance from the AAA release and Colorado Department of Transportation materials recommends details such as GPS coordinates available in Apple Maps or Google Maps, a mile marker, cross street or highway exit, plus an estimate of the direction and distance to the fire.

Officials at the department recommend pulling over to a safe location before reporting or having a passenger make the call.

Don’t try to fight a spreading wildfire, say officials. If a small fire has just started and it is plainly safe to act, an extinguisher may help. If there is any doubt, get to safety and let the professionals respond.

The department also advises slowing down in smoke, keeping vehicles in travel lanes and heeding evacuation orders under the “Ready, Set, Go!” approach promoted by Colorado fire agencies. The program encourages residents to prepare a family plan and supplies in advance (Ready), alert family and pack when a threat emerges (Set), and evacuate early when ordered (Go).