The Basics of Crash Dynamics

Since motor vehicle crashes are a leading cause of death in the U.S. it maybe helpful to understand a little bit about crash dynamics.

car crash dynamicsDuring a motor vehicle crash there are actually three collisions that happen:

  1. The Vehicle Collision: what happens at the point of impact, whether it comes from the front, back or side. The vehicle hits something and comes to an abrupt stop. This occurs in about 1/10 of a second in a front-end crash. The front end of the vehicle will crush absorbing some of the crash force, resulting in the passenger compartment coming to a more gradual stop.
  2. The Human Collision: at the time of impact, the occupants will be moving at the same speed as the car and move toward point of impact. After the vehicle comes to a complete stop, the occupants continue moving to collide with what is directly in front of them, the seat belt, the airbag or if unbuckled the windshield or other part of the car or another occupant in the car.
  3. The Internal Collision: after you have come to a complete stop, your internal organs continue moving forward. Suddenly, these organs collide with other organs or the skeletal system. This collision can cause considerable and potentially fatal injuries.

The next important aspect to realize is crash force.

Picture a vehicle going 40 mph hitting a tree. The vehicle hits the tree with the same force as hitting the ground after falling off a 50-foot cliff. So a person inside the vehicle would hit the windshield with the same force as hitting the ground after a fall from a 5-story building. The speed the vehicle was traveling greatly influences  the crash force.

You and your passengers have the best chance of reducing or avoiding injury if everyone is buckled up.

How much force is required to restrain an occupant in that amount of crash force? This is the equation: Weight of occupant x vehicle speed = force needed to restrain the  occupant.

For an example, a 10 pound infant in a vehicle moving at 30 mile per  hour would require at least 300 pounds of restraining force to keep from moving forward.

There are many factors related to injury prevention that must be considered before, during, and after a crash to prevent or minimize injuries from occurring. Here are a few examples:

The MORE energy that a car absorbs during a collision through safety features like crumple zones, seat belts and airbags, the better chance you have for survival.

It is up to the occupant to take advantage of some of these safety features, like always using a seat belt, and for using additional safety devices like car seats, booster seat or a RideSafer and maternity seat belt adjuster crash tested for safety, like the Tummy Shield.

Be safe out there.

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