The seat belt status indication is shown for ap- proximately 60 seconds whenever a seat belt is fastened or removed in the rear seats. The indi- cation can be hidden by pressing on the instrument cluster display. The physical principles involved in a frontal colli- sion are relatively simple. As soon as the vehicle is in motion → Fig. 26 , both the moving vehicle and its passengers gain movement energy. Such energy is known as “kinetic energy”. If a rear seat belt is removed while driving, the seat belt status indicator flashes for up to 60 seconds. A sound warning is also activated when driving at speeds higher than 25 km/h.
The higher the vehicle speed and the heavier the weight of the vehicle, the greater the amount of energy that will have to be released in the event of an accident. Incorrectly fastened or unfastened seat belts increase the risk of severe or fatal injuries. Seat belts will only offer the optimum level of pro- tection when they are used properly. WARNING However, the most significant factor is the vehi- cle speed. For example, when the speed doubles from 25 km/h to approximately 50 km/h (15 mph to approximately 30 mph), the kinetic energy in- creases fourfold!
The amount of “kinetic energy” depends on the vehicle speed and weight of the vehicle and pas- sengers The higher the speed and the heavier the weight, the greater the amount of energy that will be released in the event of an accident. Frontal collisions and the laws of physics Please refer to at the start of the chapter on page 34. Passengers not wearing seat belts are, therefore, not “connected” to the vehicle. In the event of a frontal collision they will continue to move for- ward at the same speed at which the vehicle was travelling before impact, until something stops them.
Because the passengers in our example are not restrained by seat belts, the entire amount of kinetic energy will only be released at the point of impact against the wall → Fig. 27 . At a speed of approximately 50 km/h (30 mph), the forces acting on the body during an accident can easily exceed one tonne (1,000 kg). These forces are even greater at higher speeds. This example applies not only to frontal colli- sions, but to all kinds of accidents and collisions. Fig. 26 Unbelted occupants in a vehicle heading for a brick wall. Fig. 27 Unbelted occupants in a vehicle striking a brick wall Owner's Manual 36