Volkswagen Tiguan Owners Manual: Frontal collisions and laws of physics

Fig. 56 A vehicle with passengers not wearing safety belts approaches a wall.

Fig. 57 A vehicle with passengers not wearing safety belts hits a wall.

The physical principles of a frontal collision are simple. Both the moving vehicle and the passenger possess energy ⇒ Fig. 56 , which varies with vehicle speed and body weight. Engineers call this energy kinetic energy.

The higher the speed of the vehicle and the greater the vehicle's weight, the more energy has to be absorbed in the crash.

Vehicle speed is the most significant factor. If your speed doubles (for example from 15 mph to 30 mph - 25 km/h to 50 km/h), the energy increases 4 times!

Because the occupants of the vehicle in the above example are not using safety belts, they are not attached to the vehicle. In a frontal collision, they will keep moving at the same speed the vehicle was moving just before the crash, until something stops them - here, the inside of the passenger compartment. Because the occupants of the vehicle in the example are not wearing safety belts, their entire kinetic energy will be absorbed by impact with the wall ⇒ Fig. 57 .

The same principles apply to people in a vehicle that is in a frontal collision on the highway. Even at city speeds of 20 to 30 mph (30 to 50 km/h), the forces acting on the body can reach one ton (2000 lbs or 1000 kg) or more. At greater speeds, these forces are even higher.

Of course, the laws of physics don't apply just to frontal collisions; they determine what happens in all kinds of accidents and collisions.