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11.09
Can Automobiles Be Made Smaller and Safer?
By George F. McClure
Government regulations are
planned to dictate a corporate average fuel
economy standard of 35.5 miles per gallon by
2016, four years sooner than Congress decreed in
the 2007 energy law. How will manufacturers
manage to meet the new standard?
One approach is to reduce the
vehicle weight, but some motorists (and buyers)
are apprehensive that a lightweight vehicle will
come out second best in a collision with a
heavier vehicle. But the physics of momentum
exchange can be mitigated by properly designed
crumple zones, provided to absorb the energy
that otherwise would be transferred to the
passengers. Other assists for the driver, built
into the vehicle, can help avoid getting into a
collision situation in the first place.
Fifty years ago, in graduate
school, I purchased a new Volkswagen bug which
lacked all of today’s safety equipment. It
didn’t even have lap seat belts until I
installed them later. But it cost only $1600 —
pretty attractive for a 40 horsepower car which
weighed 1600 pounds, but lacked a gas gauge.
There was no computer on board — crash avoidance
depended on driver skill.
Electronics aid vehicle
safety
Today, most passenger automobiles
are equipped with safety belts, an Antilock
Braking System (ABS), Electronic Stability
Control (ESC), and air bags for front and sides.
ESC cut all single-vehicle crashes by 34 percent
and single-vehicle SUV crashes by 59 percent,
according to a
2004 study by the
National Highway Traffic Safety Administration.
A 2006 study by the University
of Michigan Transportation Research Institute
found that, depending on road conditions,
between 72.9 percent and 88.2 percent of
single-vehicle rollovers of SUVs were
preventable with ESC. The Insurance Institute
for Highway Safety found that, of the 34,000
fatal vehicle crashes per year, 10,000 were
preventable with ESC.
One estimate
showed that 77 percent of single-vehicle
rollovers of cars and 80 percent of single
vehicle rollovers of SUVs were eliminated by
ESC.
ESC will be mandated by the
federal government for the 2012 model year.
The Insurance Institute for
Highway Safety conducts vehicle crash tests and
maintains data on driver deaths by vehicle type
for registered passenger vehicles one to three years old.
In 2007, the least safe vehicle was the small
pickup, followed by the small car. Pickups have
a tendency to roll over. The
safest vehicle
was the very large car, followed by the midsize
SUV.
Consumers are very
price-conscious when it comes to vehicle
features that are optional at extra cost.
Blind-spot detection and a rear-view camera
system ranked high as desirable options, at $500
and $450, but a lane-departure warning system
($500) and a collision mitigation system
($1,500)
ranked in the middle
of 19 accessory choices.
Adaptive cruise control, where
radar and sensors adjust throttle and brakes to
maintain a constant distance from the vehicle
ahead, can also sense a potential collision —
braking hard and tightening seat belts. Infrared
night vision systems with windshield projection
of images can allow the driver to see humans or
animals up to five times farther ahead than
using headlights alone,
giving the driver more
reaction time.
Buyers’ choice of vehicle and
engine size is inversely proportional to
gasoline prices. In Europe, where fuel taxes are
much higher and distances traveled tend to be
less than in the United States, passenger vehicles tend
to be smaller, and a new generation of
low-emission diesel engines is popular for fuel
economy.
Crumple zones in vehicles are
designed to absorb kinetic energy in a crash
rather than allowing it to be transmitted to the
passengers. Crumple zones can be a good
substitute for vehicle size and weight in
passenger crash protection. Perhaps the ultimate
size reduction is the two-passenger Smart Car.
Crash tests show that passengers can fare well
in collisions and that this design has greater
strength in rollovers than some larger cars. A
video of Smart Car
crash tests shows that they came
out surprisingly well.
Computer controls (ABS and ESC)
react much faster than human drivers in
dangerous road situations to mitigate potential
injury. There is some concern that drivers may
use the electronic assists to allow them to
engage in riskier behavior. But other
distractions in the vehicle cabin can make the
driver inattentive and driving more dangerous.
Consumer device distractions include on-board
entertainment systems, cell phones, texting,
email, video, and use of the Internet.
Driver distractions are risky
Department of Transportation
officials said in a report that 5,870 people
were killed and 515,000 were injured last year
in crashes where at least one form of driver
distraction was reported. Driver distraction was
involved in 16 percent
of all fatal crashes in 2008.
Driver hand-held cell phones
make use of directional signals for turns and
lane changes less likely. With only one hand on
the steering wheel there can be a tendency to
turn wide on sharp corners. Inattention to the
driving task is similar when absorbed in a
hands-free cell phone call. Simulations to mimic
driving situations found that conversing on a
hands-free cell phone while driving
(dual-tasking) negatively influenced driving
performance and that the distracting effects of
cell phone conversations were equivalent for
older and younger adults. As compared with
drivers in single-task conditions, drivers using
cell phones had 18 percent slower brake onset
times, had a 12 percent greater following
distance, and took 17 percent longer to recover
the speed that was lost following braking.
Dual-task drivers (talking on the cell phone)
were also involved in five times as many
rear-end collisions because of their slower
braking. More than 100 million cell phones are
operated while the
users are driving.
According to University of Utah
Psychologists, drivers on cell phones are
as risky as drunk
drivers.
Seven states and the District of
Columbia have outlawed the use of cell phones
while driving, while some others just require
that use be hands-free.
The threat of text messaging
Cell phone use as a driving
hazard pales in comparison to text messaging on
cell phones. For heavy vehicles/trucks, the risk
of a crash or near-crash event was 23 times as
high while texting as for non-distracted
drivers, according to
studies by the
VirginiaTech Transportation Institute (VTTI).
For light vehicles, the odds of
a crash increase with dual-tasking by the
driver:
·
Handling a CD – 2.3 times
·
Dialing a handheld device –
2.8 times
·
Applying makeup – 3.1 times
·
Reading – 3.4 times
VTTI has four recommendations:
1)
Driving is a visual task and non‐driving
activities that draw the driver’s eyes away from
the roadway, such as texting and dialing, should
always be avoided.
2)
Texting should be banned in moving
vehicles for all drivers. As shown in the table,
this cell phone task has the potential to create
a true crash epidemic if texting‐type
tasks continue to grow in popularity and the
generation of frequent text message senders
reach driving age in large numbers.
3)
“Headset” cell phone use is not
substantially safer than “hand‐held”
use because the primary risk is associated with
both tasks is answering, dialing, and other
tasks that require your eyes to be off the road.
In contrast, “true hands‐free”
phone use, such as voice activated systems, are
less risky if they are designed well enough so
the driver does not have to take their eyes off
the road often or for long periods.
4)
All cell phone use should be banned for
newly licensed teen drivers. Our research has
shown that teens tend to engage in cell phone
tasks much more frequently, and in much more
risky situations, than adults. Thus, our studies
indicate that teens are four times more likely
to get into a related crash or near crash event
than their adult counterparts.
Driving while texting (DWT) is
illegal in 18 states and the District of
Columbia. A vehicle traveling at highway speed
can travel over 100 yards during the five
seconds it takes to send or receive a text
message.
The AAA reported the results of
a survey that found, in the previous 30 days, 21
percent of all drivers had text messaged while
moving but, for drivers under age 35, 40 percent
did. Talking on a cell phone while driving was
reported by 67 percent.
A recent poll showed that 90
percent of Americans overall thought it should
be illegal for drivers to send text messages,
but only 16 percent of those between the ages of
18 and 29 agreed with an anti-texting law. Most
accidents caused by driving distraction involved
drivers aged 20 and under. Of all accidents for
that age group, 16 percent were reported to have
been distracted.
One of the most notorious uses
of text messaging was by the engineer of a
Metrolink commuter train in Chatsworth,
California just before a head-on collision with
a freight train in September 2008. He was
texting with a teenage train enthusiast. The
engineer and 25 others aboard the train were
killed.
A two-day distracted driver
summit organized by the Department of
Transportation was held recently in Washington,
D.C.. The webcast is available. Some of its
conclusions are quoted
here.
A
brochure
from the California DMV on driver distraction is
intended to educate the public about its
dangers.
George F. McClure is
Technology Policy editor for IEEE-USA
Today’s Engineer and the IEEE Vehicular
Technology Society's representative to
IEEE-USA's Committee on Transportation and
Aerospace policy.
Comments may be submitted to
todaysengineer@ieee.org.
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