Six small fires sparked at the same time Monday morning along a stretch of Lakeville Highway were caused by a passing vehicle tossing off hot metal bits as its brake system failed, fire officials said.

"It appears it was a mechanical failure of a vehicle's disc-braking system," said Brian Clarke, volunteer Lakeville firefighter.

Several callers dialed 911 at about 10:50 a.m. to report small fires on both sides of the highway. The fires were separated, three on each side, within a 200-yard area in the vicinity of Old Lakeville Road No. 2.

Whether the driver of the offending vehicle knew what was happening wasn't known as they didn't stop, Clarke said.

One of the fires began to burn a nearby eucalyptus tree, but all six were stopped before they caused property damage. The largest fire was about 20 yards across.

Winds were up to about 15 mph but the grass along the highway still is green and somewhat moist.

"If this was a month from June this fire would have taken off running," Clarke said.

At least six fire departments responded, Lakeville, San Antonio and Wilmar volunteers, Cal Fire, Rancho Adobe and Schell-Vista.

Because of the high number of engines and water trucks, firefighters and the CHP briefly directed traffic through the area.

Read all of the PD's fire coverage here