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Airbag Safety
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Today, there is a rush to design “smart” airbags. Virtually all of the
proposed solutions have, in fact, already been used
in a small number of vehicles or are technologically feasible. Safer airbag
designs include the following:
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1. Higher deployment thresholds. Most airbags are set to deploy in crashes
between 6 and 12 miles per hour.
This is far too low. Numerous studies have shown that an airbag is not needed
unless a crash is at least 18 mph.
BMW, Mercedes, and Volvo have long had systems that deploy an airbag at 18 mph
if the occupant is seat belted.
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2. Less aggressive airbags have improved airbag safety. In 1998, manufacturers introduced so-called
“second generation” airbags. To the public,
this sounded like a new design. In fact, all that manufacturers did was to use
less propellant in their design. That is,
they simply reduced the amount of propellant. Virtually nothing else changed.
Tests showed that these depowered airbags
still passed the version of FMVSS 208 that manufacturers blamed for overly
aggressive airbags. In fact, nothing prevented
manufacturers from utilizing these less aggressive airbags from the beginning.
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3. Tethers. Tethers are internal straps that cost only about $3.00. They hold
the airbag back from intruding too far into
the occupant compartment, decreasing the chance of injury. Tethers are an easy
fix, yet many airbags do not have them.
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4. Adjustable inflators. As the name sounds, the inflator is the component that inflates the airbag.
In the 1970s, the General Motors fleet with airbags had adjustable inflators. In
less severe collisions that airbag
inflated less quickly than it did in more severe collisions. This same design is
now one of the primary designs being touted
as a smart airbag. There is no good reason that adjustable inflators could not
have been used in every vehicle.
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5. Better sensors. Many airbag related injuries are directly due to sensors.
Many are too sensitive or unable to distinguish
between a minor event, such as going over a curb, and a significant event, like
a head-on collision. Sensors vary in many ways:
some are mechanical, others are electrical, and still others a combination of
the two. Also, the number of sensors and their placement
vary widely within the industry. Bad sensors can delay too long the firing of an
airbags or deploy them prematurely.
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6. Suppression systems. People, and not crash dummies, sit in vehicles. They
move. A short driver may sit close to the steering
wheel or, a passenger, may bend over to pick up or put down something or lean
over to tune the radio. A passenger who bends over
comes perilously close to the airbag. Manufacturers know this and are aware of
several systems designed to suppress the bag from firing.
It is recognized in the industry that an occupant close to an airbag is most
likely to be killed or sustain serious injuries.
Thus, some manufacturers have placed weight sensors in seats or in the floor
pan. Weight sensors help to determine if a child is in the seat
or is standing close to the airbag. Other manufacturers have developed “bias”
flaps. These are airbags designed to detect if an occupant is
in the way of the deploying airbag. If there is, the bag redirects its forces to
the side rather than directly into the occupant.
Still others are exploring the use of infrared technology to detect people who
are "out of position."
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7. Better seat belt systems. Airbags are only one part of a vehicle’s
restraint system. They are intended to supplement seat belts.
However, seat belts may be part of the problem. Many allow the occupant to move
too far forward and into the path of the deploying airbags.
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Recognizing this, many vehicles have better seat belt systems such as these that
have pretensioners. These are devices that fire at the same
time as the airbags. They pull the slack out of the seat belt and prevent
excessive forward movement. Seat belt pretensioners are widely available in
Europe and have been used in numerous vehicles in the United States for years in
addition to airbags.
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