A Crumple Zone takes the impact of a crash by, as the name suggest crumpling when a crash occurs. By doing this, the crumple zone provides a space that is designed to take the impact of a crash. The reason for the crumple zone is to increase the time from when the car hits an object to when the car comes to a complete stop. As this time increases, the force of the crash is spread longer and hence the impact of the force is minimized.
For example, if you had a crash in your car which does have a crumple zone and as a result the time to stop was increased from 0.01 seconds to 0.2 seconds. The force that your body is then subjected to is reduced from 10,000 Newton’s down to a much more bearable 500!