The
Science of Seat Belts
Today, seat belts are an
accepted part of routine vehicle operation for millions of drivers and
passengers. But the modern three-point automotive seat belt has only been
around since 1959 - and it's saved thousands of lives since its introduction.
The three-point seat belt
was the brainchild of Swedish aircraft engineer Nils Ivar Bohlin, who,
ironically, spent the early years of his career designing aircraft ejector
seats. He designed the belt as a combination lap and diagonal belt positioned
across the pelvic and rib cage.
Today's seat belts combine
Bohlin's strong three-point harness with a relatively simple pendulum and
ratchet mechanism that locks the belt in sudden-stop situations. This design
helps improve the comfort of belt wearers, as the belt is not locked in
position under normal operation.
As with any safety system,
seat belt performance is dependent on proper use and fit. If the belt is
not positioned correctly on the vehicle occupant's body, it can fail to
provide adequate safety in the event of a collision or rapid deceleration.
Follow these tips to ensure
that your seat belts provide the safety you and your passengers deserve:
-
Always wear your seat belt,
and insist that your passengers do the same. One non-restrained passenger
can seriously injure others in the vehicle.
-
Seat belts help prevent internal
injuries by spreading the force of a collision across two of the human
body's strongest areas: the pelvis and upper chest. To ensure the proper
distribution of force, the lap belt should be positioned across the upper
thighs, and the diagonal belt across the chest.
-
Never slip the diagonal belt
behind your body - the lap belt alone cannot prevent you from being thrown
forward or out of the vehicle. Use the lap belt at all times, as well.
Without this restraint, your body would be thrown under the diagonal belt
and into the dashboard or steering wheel.
-
Make sure your belt fits snugly
against your body. If it is too loose, you could be injured by being thrown
against the belt itself.
-
If your seat belts don't seem
to operate correctly, or you cannot adequately adjust them, return the
car to a dealership or qualified repair shop for assistance.
-
If your vehicle is fitted only
with lap belts (pre-1974 models), contact a dealership for an upgrade to
a three-point harness. Aftermarket kits are available for many vehicle
makes and models.
Facts:
In 2002, 39 percent of passenger
car occupants involved in fatal crashes were not wearing seat belts. (Source:
National Highway Traffic Safety Administration) [Source: pg. 3 of 12 --
http://www-nrd.nhtsa.dot.gov/pdf/nrd-30/NCSA/TSF2002/2002ovrfacts.pdf]
Seat belts save an estimated
11,000 lives each year. (Source: NHTSA)
Every 13 minutes, someone
is killed in a traffic accident. (Source: NHTSA)