Yeah, like Paul said, I'd suspect loose wiring. Does it reboot at home as well as in the car? Or only in the car?

If only in the car, I'd suspect loose wiring connections behind the sled somewhere. Another possibility: The accident caused some kind of damage to the car which made its electrical system flaky. Loosened the ground to the battery, caused the tail light wiring to get scrunched, or something like that.