Green’s Dictionary of Slang

rear-ender n.

[rear end v. (1)]

a crash in which one vehicle hits the back of that in front.

[US]C. McFadden Serial 75: It freaks me how he gets off on rear-enders.
[US]T. Dorsey Riptide Ultra-Glide 189: There was an immediate string of rear-enders. Then more crashes.