The physical principles of a frontal collision are simple. Both the moving vehicle and the passenger
possess energy ⇒ fig. 53, 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 a 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. 54.
The same principles apply to people in a vehicle that is in a frontal collision on the highway. Even at city speeds of 20–30 mph (30–50 km/h), the forces acting on the body can reach one ton (2,000 lbs or 1,000 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.
What happens to passengers not wearing a safety belt
Fig. 55 The unbelted driver is thrown forward.
Fig. 56 Unbelted passengers in the rear seats are thrown forward on top of the belted driver.
Accident statistics show that vehicle occupants properly wearing safety belts have a lower risk of being injured and a much better chance of surviving a collision. Properly using safety belts also greatly increases the ability of the supplemental airbags to do their job in a collision. For this reason, wearing a safety belt is required by law in most countries including the United States and Canada.
Although your Volkswagen is equipped with airbags, you still have to wear the safety belts provided. Front airbags, for example, are activated only in some frontal collisions. The front airbags are not activated in all frontal collisions, in side and rear collisions, in rollovers, or in cases when the condi-tions for deployment stored in the electronic control unit are not met. The same goes for the other airbag systems on your Volkswagen.
So always wear your safety belt and make sure that everybody in your vehicle is properly restrained!
Using safety belts