It was three years ago this past Christmas for us that we were sitting for 20 minutes, waiting for a drawbridge to reopen as it was lifted for a boat parade. We were the last car in line coming home from our car club Christmas dinner. 6pm, sitting and talking in our car and BANG! An illegal runs right into the rear end of our 68 Firebird at 45mph never touching her brakes.
Turns out she had a driver's license, auto ins. and was texting! Our 12 year old son was/is fine in the back seat and I give all the credit to the frame connectors we had installed on the car for saving someone's life that day. Wife and I both have lower back problems now and the illegal has been deported!
Anyway, as Sleddog says, you don't think it will ever happen to you, BUT, it can and IF it does, know ahead of time NOT after how you will be protected!