Making Cars Safer for Pedestrians
IT
is a dark, moonless night, and the jogger on the road is
wearing dark clothing. You do not see him, but your car
does.
Infrared
cameras on your bumper identify his heat signature and send
a signal to your car's computer. A warning sounds as the
brakes are automatically applied. A heads-up display projects
his image onto the windshield. Your safety belt tightens
in anticipation of an impact. But with the car slowed to
a crawl, the crash never comes and a tragedy is averted.
Such
technology is not yet available on cars sold to the public,
but it exists, thanks to research by automakers including
Mercedes-Benz and Honda and by suppliers of safety technology
including TRW, Siemens and Autoliv. The research has been
conducted with some urgency, since manufacturers doing business
in Europe have agreed to provide pedestrian-protection features
in a two-stage commitment that goes into limited effect
there in October 2005 and gets considerably stronger in
2010. Automakers have agreed to similar standards that take
effect in Japan next year.
Many
of the changes being made to conform with the first phase
involve passive systems, like redesigned bumper and hoods.
But active, high-tech systems seem inevitable, including
fiber-optic and radar sensors, exterior cameras and outside
air bags that would deploy instantly when an accident occurs
- or even before it takes place.
Motor
vehicles kill more than 7,000 pedestrians a year in the
European Union, about 20 percent of all traffic-related
fatalities. In Japan, the 2,700 pedestrians who die annually
account for 30 percent of the traffic toll.
But
the issue does not have a high profile in the United States,
where 5,000 pedestrians die each year, 13 percent of total
fatalities. Yet even in the absence of a public outcry,
and without pending legislation, pedestrian-safety technology
has begun to appear on American-market cars and trucks.
People
are rarely "run over," unless they are lying in
the road. Instead, they are thrown up and onto the car,
where their heads strike the hood or windshield. Since more
than half of pedestrian and cyclist fatalities involve head
injuries, many new cars, possibly including the 2006 Mercedes-Benz
S-Class sedan, will have a softer "deformable"
hood. In some cases, the hood will rise at the rear in a
crash.
A
spokesman for Siemens, the German electronics giant, said
the company had developed a bumper-mounted fiber-optic system
that can, within 3 milliseconds, or three-thousandths of
a second, determine whether the vehicle has just hit a person
or an inanimate object like a lamppost. Within 30 to 60
milliseconds, the system can raise the rear of the hood
several inches to create what the spokesman, David Ladd,
called "a catching device to absorb the impact energy."
Since the hood would probably be designed to deform on impact,
cushioning a blow, it would be a safer obstruction than
unyielding steel.
Mr.
Ladd said Siemens had development contracts to explore the
technology with two German companies.
A
similar "active hood" under development by TRW
uses sensors that instruct the hood to rise at the rear,
said a spokesman, John Wilkerson. He added, however, that
such systems might not be effective with larger, higher
sport utility vehicles because "the head impact will
be in the very front-end area." S.U.V. systems have
focused on passive protection, like reducing sharp edges
and softening front ends. Because of concerns about pedestrians,
rigid "brush bars" have largely disappeared from
European S.U.V.'s.
The
number of S.U.V.'s on American roads presents a challenge.
Dr. Samir Fakhry, chief of trauma services at Inova Regional
Trauma Center in Falls Church, Va., said people hit by cars
were usually thrown onto the hood, but when hit by a large
S.U.V., "there's no way they'll get up there."
"Instead,"
he said, "they'll go up in the air or under the vehicle."
According
to a study published in the June issue of the journal Injury
Prevention, pedestrians hit by light trucks, a category
that includes S.U.V.'s, have a 300 percent higher risk of
severe injury than if they were hit by passenger cars. The
joint study, by Harborview Injury Prevention and Research
Center in Seattle and the Center for Applied Biomechanics
at the University of Virginia, analyzed federal data on
542 victims.
Dr.
Fakhry said that medical research work on pedestrian safety,
especially involving impacts with S.U.V.'s, had lagged behind
other automotive safety issues. Inova's pedestrian research
is primarily financed by Honda through the federal Crash
Injury Research and Engineering Network, known as Ciren.
The
National Highway Traffic Safety Administration has conducted
research on pedestrian safety, but after some consideration
in the early 1990's it decided not to go ahead with requirements
for automakers. In the absence of legislation, price and
consumer demand are driving the changes.
Autoliv
North America is also working on technology in which sensors
would act to raise the hood; a spokesman, Patrick Jarboe,
said incorporating such a system into a car would be likely
to cost $200. "If customers demanded this kind of technology
in the U.S., it could become standard within a year,"
he said.
Honda,
a leader in pedestrian safety technology, has quietly incorporated
some innovations into most of its current models without
charging extra. The Accord, for instance, has windshield
wipers that absorb energy when struck, hood hinges that
bend on impact and spaces that allow the hood and fenders
to deform, cushioning a blow. Andy Boyd, the company's public
relations manager, said two million Honda and Acura cars
had some or all of these elements.
Honda
also developed the world's first pedestrian dummy, called
Polar II in its current form. According to Honda's senior
safety engineer, Tomiji Sugimoto, the dummy mimics the performance
of the human leg, chest and shoulders in a collision with
a car. Mr. Sugimoto added that there was considerable research
on children's safety inside vehicles, but that little was
available on how their bodies fared in pedestrian accidents.
Other
carmakers have also introduced new safety designs, though
Honda's are perhaps the most far-reaching. The underside
of the aluminum hood on the Mazda RX-8 sports car has a
deforming egg-crate-style "shock cone" design
without rigid ribs, a Mazda spokesman, Jeremy Barnes, said.
Like
Honda, DaimlerChrysler conducts extensive pedestrian safety
testing, and some features are likely to be incorporated
into the 2006 Mercedes-Benz S-Class luxury car, including
an active hood-raising system. A Mercedes safety spokesman,
Dirk Ockel, said that passive safety measures on new models
might include a new hood design with fewer support ribs
to stiffen it, a rearranged engine compartment to give more
clearance above unyielding engine parts, and modified bumpers
and spoilers.
Mr.
Ockel said Mercedes saw the greatest potential for reducing
pedestrian injury in active safety systems that promote
accident avoidance. One such system, he said, automatically
applies the brakes when electronic sensors detect that an
accident may be imminent. "In many events, the collision
can even be fully avoided," he said.
The
2003 S-Class introduced Mercedes's "pre-safe"
system that tightened the safety belts and moved reclined
seats upright as much as 6 seconds before a crash. In the
future, the company says, such systems could be enhanced
by radar to provide what Mercedes says are accurate three-dimensional
digital models of the road and objects on it.
Mr.
Wilkerson of TRW said that pre-crash sensors based on video
technology would disploy front-mounted active systems even
before impact. These systems, still in the concept stage
at TRW, include an "active bumper" whose lower
area would move forward to absorb crash energy, and a grille-mounted
air bag to catch pedestrians before they are struck by the
car itself. Mr. Wilkerson said such video systems would
need to be highly accurate, with a wide field of view.
Honda's
pedestrian-sensing night vision technology will be an option
this year on the Honda Legend luxury sedan in Japan. The
infrared system is intended to identify pedestrians from
an indistinct blur of dark images, wrap them in an orange
frame and display the image through a heads-up display projected
on the windshield.
Toyota
and General Motors have also developed night-vision systems,
though they do not share Honda's focus on pedestrians.
Dr.
Fakhry said that any onboard systems, active or passive,
would have to work in conjunction with common-sense public
safety campaigns. "Drivers have to be on the lookout
for pedestrians," he said. (Source: SmartMotorist.com)
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