These risk factors explains why some people are “walk away” after an auto accident and others are taken by the ambulance. These risk factors are taken from the research summered in the textbook "Whiplash and Mild Traumatic Brain Injuries" by Arthur C. Croft, PhD, DC, MSc, MPH. It is common to think that a minor car accident should result in no injuries.
Researches have been trying to establish the “threshold of injury” for car accidents, but to date no such conclusion can be made. You do not get injured from the bending of metal or braking of plastic but from how quickly you are thrown around in the car.