You can’t tell by looking. There are parts behind the bumper that are designed to absorb the force, but they are only good for one good bump. I had a cop rear end me once. He gave me all the information. The next day I looked at it and it had a few small scratches. I took it into the dealer (Mazda) and they said just a minute. They came back with a few blocks of Styrofoam. Replaced the ones behind the bumper and changed me $1.75 for each of the three. I never contacted the cop.