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The National
Highway Traffic Safety Administration reports that on average, 7,258
people were killed each year from 1992 to 1996 when they were fully or
partially ejected from their vehicles in accidents. Two-thirds of
those deaths occurred when cars and trucks rolled over several times.
The highest rates
of being thrown out of a window -especially a side window -- occur in
sport-utility vehicles, vans and pickup trucks. With cars, such an
event is half as likely. In 1996, more than half of all deaths caused
by ejection from a vehicle involved sport-utilities.
"SUVs tend to
be involved in a disproportionate number of rollovers, and ejections
are related to rollovers," said Stephen Summers, a NHTSA engineer
who is part of a team researching how glazing side windows with
special plastics might decrease the number of fatalities from
ejections in all kinds of vehicles.
To put this more
graphically, regulators are looking at what they can do to prevent
people from dying when their sport-utes -- and other types of vehicles
-- roll over in accidents and bodies, or limbs, fly through the front
and rear side windows after the glass shatters into tiny pieces. About
98 percent of people injured in such accidents were not wearing their
seat belts, and many of them died from head injuries.
NHTSA said the
problem has taken on more urgency as sport-utility vehicles and
trucks, which have a higher center of gravity and thus can flip more
easily, have become increasingly popular with consumers. This has
caused researchers to focus on how to prevent injuries in
sport-utility and light-truck accidents.
For six years, the
agency has been studying what its engineers call "ejection
mitigation" -- or how to keep people inside their vehicles in
accidents. Seat belts are a big help, as are various types of glass
that don't shatter easily and that absorb some of the energy from a
crash.
NHTSA is studying
several kinds of laminated glass that resemble the type used in
windshields. Laminated glass doesn't shatter into tiny pieces; instead
it shows cracks or "stars" when it is hit. It also does a
decent job of keeping occupants from sailing through the front window.
The rest of the
windows in most vehicles are made of tempered glass, which is designed
so that, when broken, it shatters into little bits that won't gouge
the vehicle's occupants. But it can be broken more easily than
laminated glass and does not help hold an occupant in the vehicle.
What researchers
have found -- and this seems pretty obvious -- is that keeping people
inside a vehicle dramatically increases their chances of surviving.
"Preventing ejections from side windows is one of the few simple
things you can do to prevent injuries in a rollover, which is an
extremely violent event," Summers said.
But the four types
of glazing the agency has been examining with the help of glass
companies and outside safety experts present installation and
technological challenges.
There are
unresolved questions about what kinds of glazing would work best, what
kinds of injuries people wearing seat belts would have if their heads
hit the window and how much redesign of the door frame would be
required. One estimate is it would cost $48 to $80 per car to use
glazed side windows, depending on the material used.
Richard Morrison,
owner of Glass & Glazing Forensics in Southfield, Mich., said more
research has to be done on injuries from "rebound," which
refers to what happens when a person's head hits the windows and
rebounds backward.
Morrison is
worried about increased lacerations, because some of the glazed glass
does not fall out of the frame. "There doesn't seem to be a
perfect solution," he said.
Some carmakers,
such as Volvo and Mercedes-Benz, already offer glazed windows as
anti-theft devices.
Volvo markets a
$240 glazed-glass option on its S-80 sedan. All four side windows are
laminated to prevent "smash and grab," a theft problem that
has led to more use of such glass in Europe.
Solutia Inc., in
St. Louis, which manufactures plastic used in glazed windows, wants
the government to propose a laminated glass standard. NHTSA's current
side-window standard focuses on how the tempered glass shatters and
the dimensions of the pieces.
"The
technology is here today. What we need is a performance standard from
NHTSA. It's a little frustrating for us because lives could be saved.
Don't delay a good solution to pursue a perfect solution," said
Robert Esposito, manager of automotive development for Solutia.
Glass experts who
have worked with the agency are skeptical that the research will ever
lead to a rule, especially since an increasing number of automakers
are offering side air bags, some of which cover the window and offer
ejection protection. NHTSA said the two side air bag systems it tested
were helpful in preventing people from being thrown out the window.
The easiest
solution, everyone on the NHTSA glazing project agreed, is for people
to use seat belts.
"This whole
ejection thing is a problem of belt use," Summers said. "If
we could get 100 percent belt use, it wouldn't be an issue at
all."
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