The same happened to me last year, though I did not have a tow hitch, but the other guy was driving an old dodge sundance and hit my bumper and left spring shackle which ripped into his grill and tore his radiator and condensor up and on top of his engine and the rest of the car slightly scratched the gas tank and bounced off my left rear tire. the only damage I had was my bumper bent a bit into the rear hatch. Strangely and amusing to me, he was still able to drive off the freeway to the next exit while his hood kept flying up and blocking his view, he would stop and slam it down but it would just keep going up because his motor mount was broke and his engine kept pushing up on the hood that now had a busted latch. That happened to him twice until he just stuck his head way out his window to see where he was going till we got off that long offramp to the gas station at the end of the ramp, I laughed so hard! I just sledge hammered the bumper down out of the way of the hatch at the air show we were headed to so I could grab my folding chairs under the rest of the gear I had back there and sit in the shade and enjoy the show through the rear window. His car was completely totaled, and he had no insurance, and I felt more sorry for him since he was sick as a dog and was headed to his doctor, which I'm sure lead to him hitting me after I had been stopped in traffic for at least 15 seconds before impact. I guess he didn't see me, who knows, but he was way too sick to fake and I stayed with him till his wife showed up to take him to the doctors, since he refused to let me call an ambulence, but he had no injuries from the wreck. I never even reported the accident to get him into trouble, just reported to my insurance that a fender bender occured that involved the other "un-named" car damaged not mine. I'm getting a better bumper later anyway, so not a bother to me much, I was more bothered on missing alot of the airshow. I later found out he passed away, not from the wreck, but he was sick with cancer, and in the final stages, just unable to afford hospitalization.....ambulance.....insurance. His wife invited me to the funeral, but I ended up getting injured at my job and never made it. I'm just glad I wasn't an "A"-hole with the guy as I did have every right to be pissed off, but for some reason not this time.
WOW! SORRY FOR SUCH A LONG STORY!