At least one lane of the 15 Freeway remained closed as of 11 p.m. Highway 138 was closed at one point, but it has since reopened.
"I was hoping to go home, but didn't quite work out like that for at least six hours. It's been backed up all day. It's been tough," said Lawrence Nelson of Victorville.
The blaze began around 5:30 p.m. and quickly grew. It has charred 110 acres and was 10 percent contained.
"It started with a small fire and then it grew bigger and bigger, and more and more traffic, bumper to bumper. Everybody's out of their cars. It's hot, just a lot going on today," said Dynesha Newton of Rialto.
Aircraft hit the flames hard from above as crews along the freeway battled to keep the blaze from jumping the road.
As firefighters work to gain the upper hand on the blaze, drivers can only sit and wait. Many truckers called it quits along the road.
"I just give up and I park on the side. It's really bad," said Jesus Posada of Colorado.
Investigators say the cause of the fire remains under investigation. They say they don't know if an earlier truck fire may have been a factor.