Auto Crash Examples

These videos show how people are injured in low speed as well as high speed collisions.

Low speed rear end collisions

These are examples of low speed rear end collisions. Occupants are not necessarily injured in these collisions, however it is certainly possible.

Rear end head acceleration 7.8g

The car from the rear is only traveling at 8mph. Because the occupant’s head is not against the headrest, the resulting head acceleration is 7.8g. This is enough to cause injury given the short span the acceleration occurs within.

Rear end head acceleration 6.0g

In this case, both of the occupant’s hands are on the steering wheel. This offers some protection as the car accelerates forward at the time of impact. The resultant head acceleration in this 4.4 mph collision is 6.0g.

Rear end head acceleration 5.7g

In this 7.7mph rear end collision, the occupant’s head is near the head rest which lessons the head acceleration. If the head was all the way against the headrest at the time of impact, the head acceleration would be at its least.

Rear end head acceleration 7.7g

At just 2.3 additional mph with this rear end collision, there is an additional 2.0g of head acceleration. Head rest position still plays a vital role in reducing the degree of head acceleration. Greater head acceleration generally translates to greater forces on the cervical spine and increases the chance and severity of injury.

Rear end head acceleration 6.3g

This is a good example of what happens when the occupant’s head is against the headrest. Notice the pony tail is up and over the headrest as this occupant is intentionally maintaining her head in that position before the impact. There is still over 6g of force translated to the head even with her head against the headrest.

Rear end head acceleration 4.0g

With this rear end collision example, the occupant’s head is significantly far from the headrest. Even with a head acceleration of only 4g (or 4 times normal gravity) there is a significant compressive effect as the head travels backwards toward the barrier that sends the head back in the forward direction. This swift change of directions is what is referred to as whiplash.

Rear end head acceleration 7.1g

This example of a rear end collision involves the same subject and car as the 4.0g example. There is 2.6 additional mph in this example translating to a 3.1g increase from the previous example. This causes the head to accelerate equivalent to 7.1g. That is seven times normal gravity. If a human head weighs 11 pounds, that is as if the occupant’s head weighs 78lbs! If a 78lb object whips forward on the rebound along with the compressive forces, the ligaments holding the vertebrae together are damaged. Note there is very little to no damage to the vehicle.

High speed rear end collisions

These are examples of high speed rear end collisions. Note the vehicle damage is not necessarily consistent with the violence and measure head G forces. These G forces in such a small time window is what causes the tissue damage occupants experience.