“....then they will touch off car bombs in the backed up traffic creating a chain reaction of exploding cars.”
When a car catches fire, short of having the means on site to extinguish the fire, they usually just quickly become engulfed in flames and burn up rather than exploding.
It wouldn’t be “a” car sitting out by itself.
In a traffic jam hundreds if not thousands of cars are closely packed together not to mention the possibility of fuel trucks in the mix.