发信人: ferrygao (发糕发糕刷题拿大包), 信区: Automobile
标 题: 走路被撞死的越来越多了
发信站: BBS 未名空间站 (Tue Jun 12 11:06:12 2018, 美东)
ON FOOT, AT RISK
Study highlights rising pedestrian deaths, points toward solutions
The March crash of an Uber vehicle that killed a woman in Tempe, Arizona,
was unusual for involving a self-driving vehicle. But in other ways, it was
typical of fatal pedestrian crashes: an SUV traveling on an urban arterial
road struck a person crossing midblock in the dark.
Pedestrian deaths have jumped 46 percent since reaching their lowest point
in 2009, as pedestrian crashes have become both deadlier and more frequent.
The increase has been mostly in urban or suburban areas, at nonintersections
, on arterials — busy roads designed mainly to funnel vehicle traffic
toward freeways — and in the dark, a new IIHS study shows. Crashes were
increasingly likely to involve SUVs and high-horsepower vehicles.
"Understanding where, when and how these additional pedestrian crashes are
happening can point the way to solutions," says IIHS President David Harkey.
"This analysis tells us that improvements in road design, vehicle design
and lighting and speed limit enforcement all have a role to play in
addressing the issue."
A total of 5,987 pedestrians were killed in crashes in 2016, accounting for
16 percent of all crash fatalities. The number of pedestrians killed each
year has declined 20 percent since 1975, but the 2016 toll was the highest
For the new study, IIHS researchers looked at pedestrian crash trends during
2009–16 to pinpoint the circumstances under which the largest increases
occurred. Using federal fatality data and crash numbers, the researchers
looked at roadway, environmental, personal and vehicle factors to see how
they changed over the study period. They also looked at changes in the
number of pedestrian deaths relative to the number of pedestrians involved
Pedestrian crashes have become both deadlier and more frequent. The increase
has been mostly in urban or suburban areas, away from intersections, on
busy main roads and in the dark. Crashes are increasingly likely to involve
SUVs and high-horsepower vehicles.
PEDESTRIAN DEATHS, 2009-16
By land use
By road type
collectors and local roads +9%
interstates and freeways +49%
By light condition
dawn or dusk +27%
The researchers found that not only did pedestrian crashes increase, they
also became deadlier. Deaths per 100 crash involvements increased 29 percent
from 2010, when they reached their lowest point, to 2015, the most recent
year that data on all crashes, including nonfatal ones, were available.
From 2009 to 2016, the largest increases in pedestrian deaths occurred under
the circumstances that historically have seen the highest numbers of
pedestrian fatalities. Pedestrian deaths increased 54 percent in urban areas
, which include both cities and what most people consider suburbs. They also
increased 67 percent on arterials, 50 percent at nonintersections and 56
percent in the dark.
Although pedestrian crashes most frequently involved cars, fatal single-
vehicle crashes involving SUVs increased 81 percent, more than any other
type of vehicle. The power of passenger vehicles involved in fatal single-
vehicle pedestrian crashes, as measured by the ratio of horsepower to weight
, also increased, with larger increases at the top of the scale.
Among age groups, the largest increase in pedestrian fatalities per
population was for people ages 20–69.
Designing roads for pedestrians
The large increase in pedestrian deaths on arterials isn't surprising. These
roads often have a shortage of convenient and safe crossing locations.
"When people are forced to walk long distances to the nearest signalized
intersection, they are more likely to choose the riskier option of sprinting
across multiple lanes of traffic," Harkey says. "Communities can improve
safety by providing more options to safely cross."
But, Harkey warns, it's not enough to simply paint more crosswalks on the
pavement. Midblock crossings need features that alert drivers to stop, such
as pedestrian-activated beacons.
One example is the pedestrian hybrid beacon, which stays dark until a
pedestrian pushes a button, at which point it flashes yellow, and then moves
to solid yellow before activating two solid red lights. This type of beacon
, formerly known as a HAWK, has been shown to reduce crashes (see "Double-
red signal reduces crashes at crosswalks," Sept. 28, 2010).
Other improvements, such as curb extensions or median crossing islands, can
shorten the distance people must walk across or allow them to traverse just
a couple of lanes and a single direction of traffic at a time.
Adding sidewalks is an obvious way to reduce the risk to pedestrians walking
along a road.
These elements can be part of broader reconfigurations known as road diets,
in which the number of travel lanes for vehicle traffic is reduced. In
addition to reducing the number of lanes for pedestrians to cross and
sometimes providing room for bike lanes, road diets have been shown to lower
"Good design should prioritize the safety of all road users," Harkey says. "
It's possible to improve streets for pedestrians while still allowing
vehicle traffic to get where it needs to go."
High-Intensity Activated crossWalK
A woman crosses at a pedestrian hybrid beacon in Arlington, Virginia. The
beacon remains dark until a pedestrian activates it. First, it flashes
yellow before moving to solid yellow and then to solid double red.
Reining in speed increases
Of course, allowing vehicles to get where they need to go doesn't mean they
need to go quite as fast as people are used to.
Faster speeds make for more frequent and deadlier crashes. The faster a car
is moving, the less time the driver has to see a pedestrian and slow or stop
. Higher impact speeds also result in more injurious crashes.
Reliable information on vehicle speeds is not available in fatality data,
but IIHS researchers did find that the vehicles involved in fatal pedestrian
crashes, like the overall vehicle fleet, are increasingly powerful.
Previous IIHS research has shown that vehicles with higher horsepower-to-
weight ratios tend to be driven faster and are more likely to violate posted
speed limits (see "Vehicles are packing more horsepower, and that pushes up
travel speeds," May 24, 2016).
Despite the dangers of high speeds, the story of speed limits in recent
decades has been one of continual increases.
In addition to lower speed limits, broader use of speed cameras to enforce
existing limits is a proven solution. Institute research has shown that
automated speed enforcement reduces speed limit violations and injury
crashes (see "Speed cameras reduce injury crashes in Maryland county, IIHS
study shows," Oct. 1, 2015).
Some risks to pedestrians could be lessened by making changes to vehicles.
A large majority of pedestrian fatalities occur in the dark, and that number
increased much faster than the number of pedestrians killed in other light
conditions. In 2016, 4,453 pedestrians were killed in the dark, compared
with 1,290 in daylight and 205 at dawn or dusk.
Although better street lighting may be needed in some locations, another
obvious solution is better headlights. IIHS has been working to encourage
improvements in this area through its headlight rating program, launched in
2016. Headlights have been gradually improving. In the 2016 model year,
there were just two models with available good-rated headlights. So far for
the 2018 model year, there are 26 good headlight packages.
Vehicles with front crash prevention systems that recognize pedestrians also
would help — particularly if they are designed to work in low light. A
recent HLDI analysis found that Subaru vehicles equipped with pedestrian
detection had claim rates for pedestrian injuries that were 35 percent lower
than the same vehicles without the system.
Finally, vehicle design changes could help lessen the severity of crashes,
especially when it comes to SUVs. These make up an increasingly large
percentage of registered vehicles, and previous studies have found that SUVs
, pickups and vans are associated with a higher risk of death or severe
injury to pedestrians. Such vehicles have higher and often more vertical
front ends than cars and are more likely to strike a pedestrian in the head
or chest. Changes in the front-end design of these vehicles could help
lessen the severity of injuries when they strike pedestrians (see "Softer
vehicle fronts and pedestrian detection systems could reduce pedestrian
deaths, injuries," Dec. 30, 2013).
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