English to Spanish Medical Medical: Health Care the use of seatbelts

The human collision
Imagine running as fast as you can - into a wall. You´d expect to get pretty banged up. Do you think you could stop yourself if the wall suddenly loomed up when you were two feet away from it? This is exactly the situation you face when the front of your car hits something at only 15 miles an hour. The car stops in the first tenth of a a second, but you keep on at the same rate you were going in the car until something stops you-the steering wheel, dashboard or windshield-if you´re not wearing your safety belt. Bad enough at 15 miles an hour, but a 30 miles you hit "the wall" four times as hard as you would at 15. Or put it another way, with the same impact you´d feel if you fell three stories.
A properly worn safety belt keeps that second collision - the human collision-from happening.

la colisión humana? la colisión para el cuerpo humano?