94 Safety belts
- Failure to pay attention to the warning
light that comes on could lead to person-
al injury.
Why safety belts?
Frontal collisions and the law of physics
Frontal crashes create very strong forces for
people riding in vehicles.
Fig. 84 Unbelted occupants in a vehicle head ing fo r a
wall
Fig. 85 The vehicle crashes into the wall.
The physical principles are simple. Both the
vehicle and the passengers possess energy
which varies with vehicle speed and body
weight . Engineers call this energy "kinetic en-
ergy ."
The higher the speed of the vehicle and the
greater the vehicle's weight, the more energy
that has to be "absorbed" in the crash .
Vehicle speed is the most significant factor.
If
the speed doubles from 15 to 30 mph (25 to
50 km/h), the energy increases 4 times!
Because the occupants in this vehicle are not
using safety belts¢
fig. 84, they will keep
moving at the same speed the vehicle was
moving just before the crash, unt il something
stops them - here, the wall ¢
fig. 85 .
The same principles apply to people sitting in
a vehicle that is involved in a frontal collision .
Even at city speeds of 20 to 30 mph (30 to 50
km/h), the forces acting on the body can
reach one ton (2,000 lbs, or 1,000 kg) or
more . At higher speeds, these forces are even
greater.
People who do not use safety belts are also
not attached to their vehicle. In a frontal colli-
sion they will also keep moving forward at the
speed their vehicle was travell ing just before
the crash . Of course, the laws of physics don't
just apply to frontal collisions, they determine
what happens in all kinds of accidents and col-
lisions .
What happens to occupants not wearing
safety belts?
In crashes unbelted occupants cannot stop
themselves from flying forward and being in-
jured or killed. Always wear your safety belts!
Fig. 86 A driver not wearing a saf ety be lt is violent ly
thrown forward
Unbelted occupants are not able to resist the
tremendous forces of impact by holding tight
or bracing themselves . Without the benefit of
safety restra int systems, the unrestrained oc-
cupant will slam violently into the steering
wheel, instrument panel, windshield, or what-
ever else is in the way .!>
fig. 86. This impact
with the vehicle interior has all the energy
they had just before the crash.
Never rely on airbags alone for protection .
Even when they deploy , airbags provide only
additional protection . Airbags are not sup-
posed to deploy in all kinds of accidents. Al-
though your Audi is equipped with airbags, all ..,
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