Skip to content

How Roadside Ignitions Threaten our Wildlands


Whether intentional or accidental, roadside fires are the leading cause of local wildfires.

If you take your car in for a tune-up today, you could be preventing a wildfire tomorrow. At least one California wildfire was caused by a roadside ignition over the summer, and most of the major wildfires in Orange County have been started at the side of a road.

According to Orange County Fire Authority (OCFA), broken catalytic converters and dragging tow chains are the most common causes of these roadside ignitions, aside from the wildfires caused by arson. And as the Santa Ana Wind season picks up, a tiny spark from a low-hanging chain can set off a devastating blaze. 

High winds combined with dry weather are the warning signs for wildfires. Ongoing drought conditions in Orange County have led the National Interagency Fire Center to predict “above normal” significant wildfire potential to persist in Southern California mountain areas through at least October. This means that a faulty car part – even a blown tire – can cause enough heat to create a flame.

“When a catalytic converter breaks, the combustion can send pieces flying from the car, and those super-heated pieces of ceramic and metal can easily ignite roadside vegetation,” says George Ewan, OCFA Wildland Fire Defense Planner. “At this time of year, dried grass along roadsides is tinder waiting to burn.”

Non-native grasses are common along local wilderness-adjacent roads, and those weeds also contribute to the fire threat. If a car pulls to the side of the road and parks on top of a weed-filled area, the heat from the car can easily light the dry grass underneath. While replacing these grasses with native groundcover or hardscape is a long-term goal, a short-term solution is to never pull over into a weedy patch along the side of the road. If you need to pull off of the road, try to find a paved or dirt pullout whenever possible.

OCFA has brought together a working group of a variety of organizations including CalTrans, Southern California Edison, the County of Orange, the Transportation Corridor Agencies, Irvine Ranch Conservancy, and others to work together on strategies to reduce the threat of roadside fire ignitions. Orange County residents have a critical part to play in preventing fire along roads by reporting suspicious or dangerous activity and by keeping their car tuned up to avoid sparks and backfiring.  Several major fires have started from car sparks and combustion, including the Freeway Complex Fire in 2008 which burned 200 structures and 30,305 thousand acres.

“It seems like such an easy thing to do,” says Ewan, “but maintaining your car can help save tens of thousands of acres of our local wilderness areas.”

Fire Watch volunteers are trained by OCFA and Irvine Ranch Conservancy to watch for sources of roadside ignitions. Even though the Conservancy manages Fire Watch activities for landowners such as OC Parks and City of Irvine, volunteers are not posted inside the park areas, but rather along roadsides.

The Fire Watch posts were selected by the Conservancy based on past fire ignition locations as well as high potential for arson-related activity. Volunteers watch for suspicious activity, but also inform the public about fire danger. Members of the public can also participate by reporting suspicious or dangerous behavior.

“As soon as the winds pick up, the public should be on high alert,” said Dave Raetz, Irvine Ranch Conservancy Deputy Director. “Watching for seemingly little things like a cigarette thrown out the window or a car pulled over onto dry weeds can help prevent a wildfire.”