I actually seen a car start on fire before.
Was late at night and was going down a busy road, three lanes each way seperated by a mediam.
There are several lights up and down this strech of road.
We were stopped at a light headed East, the westbound traffic was stopping to ( the light just changed), and the one car stopped, the car behind him stopped, but the next car didnt. He didnt even touch the brakes, bang at 50mph ( I assume 50, speed limit is 45 there) he rearend this car, it shot the car into the car of the head of the next one. That car went out into the intersection.
A few seconds later the car that started it all caught on fire, and was burning up pretty bad.
Everyone ran over to help out, but the guy that started it there was no helping, he had died on impact.