FWIW several years ago I got cut off and then the chick hit her brakes, I'd estimate at the time of impact I had managed to slow down to a bit under 30 mph - pushed her spare wheel in her tailgate, the tailgate in the cargo compartment, and the bumper was now touching the rear wheels. However, 2ft displacement in the front end - from what I've seen tho I'd say he must have been going a whole lot faster than 30, 55 sounds more like it.