Table of Contents
Advertisement
108
S a fety
belts
Why safety
belts?
Frontal collisions and the law of physics
Frontal crashes create very strong forces for
people riding in vehicles .
Fig. 111
Unbe lted occupa nts in a vehicle heading for a
wall
Fig. 11 2
The vehicle cras hes into t he wall.
The physical principles are simp le. Both the
vehicle and the passengers possess energy
which varies w ith vehicle speed and body
weight . Engineers call th is 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 doub les from 15 to 30 mph (25 to
50 km/h) , the energy increases 4 t imes!
Because the occupants in this vehicle are not
using safety belts ¢
fig. 111,
they will keep
moving at the same speed the vehicle was
mov ing just before the crash, unti l something
stops them - here, the wall ¢
fig . 112 .
The same pr inciples 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 act ing 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 saf ety belts are also
not at tached to their vehicle. In a frontal colli -
sion they wi ll also keep moving forward at t he
speed their vehicle was travell ing ju st 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-
lis ions.
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 safe ty belts!
Fig. 11 3
A dr iver not wea ring a safety belt is viole ntly
thrown fo rward
Unbelted occupants are not able to resist the
tremendous forces of impact by hold ing tight
or bracing themse lves. Without the benefit of
safety restra int systems, the unrestrained oc-
cupant will slam violently into the steering
wheel, instr ument panel, w indshield, or what -
ever else is in the way ¢
fig . 113.
This impact
with the vehicle inte rior has all t he energy
t hey had j ust before t he crash.
Never rely on airbags alone for protection .
Even when they deploy, airbags provide only
additional prote ction . Airbags are not sup-
posed to deploy in all kinds of accidents. Al-
t hough your Audi is equipped wi t h airbags, all
vehicle occupants, including the driver, must
wear safety belts cor rectly in order to m ini-
mize the risk of severe inj ury or death in a
crash.
Advertisement
Table of Contents
