Toyota, Honda and Nissan Models Perform Best
For the first time the Insurance
Institute for Highway Safety has evaluated the
performance of minivans in side impact crash tests.
The tests simulate crashes in which SUVs or pickup
trucks strike the sides of minivans. These are
the kinds of crashes that can occur at intersections
when a vehicle runs a red light or stop sign.
Three minivans with standard side airbags — Toyota
Sienna, Nissan Quest, and Honda Odyssey — earned
the Institute's highest rating of good (side airbags
were optional in the 2005 Sienna). The Sienna
and Quest earned the added designation of "best
pick" for side crash protection. The Sienna
also is a "best pick" in the Institute's
frontal offset test, so this minivan with side
airbags is a "double best pick" for
front and side crashworthiness.
The Ford Freestar with optional side airbags earned
a rating of acceptable. When the Freestar and
Mazda MPV were tested without their optional side
airbags, both earned the lowest rating of poor
(the MPV with optional side airbags wasn't tested).
These ratings reflect performance in a side impact
crash test in which a moving deformable barrier
strikes the driver side of a passenger vehicle
at 31 mph. The barrier weighs 3,300 pounds and
has a front end that is shaped like the front
of a typical pickup or SUV. In each side struck
vehicle are two instrumented dummies the size
of a small (5th percentile) woman, one positioned
in the driver seat and one in the rear seat behind
the driver.
The Institute didn't test the Chevrolet Uplander
or the Dodge Grand Caravan/ Chrysler Town &
Country minivans because design changes intended
to improve their performance in side impact crashes
are under way. The Institute will test these vehicles
plus the redesigned Kia Sedona early next year.
"The risk of dying in frontal crashes has
been reduced dramatically in recent years,"
said Institute chief operating officer Adrian
Lund. "But there haven't been the same risk
reductions in side impact crashes. We expect this
test to drive manufacturers to make side airbags
with head protection standard and improve side
structures to better protect occupants in side
impacts."
Federal testing doesn't reflect many real-world
crashes. The federal government also conducts
side impact tests for consumer information but
uses a barrier that was designed in the 1980s
when cars represented most vehicles on the road.
The height of the barrier's front end is below
the heads of the dummies that measure injury risks
in side-struck vehicles. The federal test doesn't
assess the risks of head injury from impacts with
vehicles like SUVs and pickups.
modify the moving deformable
barrier used in the federal test so the front
end represents that of an SUV or pickup. The result
is a barrier that's taller and higher off the
ground.
All of the minivans in this round of tests performed
well, earning four or five stars, in the government's
side impact test. In contrast, the range of performance
in the Institute's test indicates significant
differences in how well these vehicles would protect
their occupants in crashes with SUVs or pickups.
Since SUVs and pickups now make up nearly half
of new passenger vehicle sales each year, the
type of crash simulated in the Institute's test
is becoming more common.
Top performers have side airbags and structures
that resist major intrusion: The minivans that
earned good ratings in the side test are equipped
with curtain-style airbags designed to protect
the heads of people in all three rows of seats.
"In each of the top-performing minivans,
the curtain airbags did a good job of keeping
the dummies' heads from being struck by the intruding
barrier," Lund said. "This is important
because head injuries are factors in many serious
side impact crashes, especially when the striking
vehicle is a pickup or SUV with a tall front end.
Manufacturers should follow the lead of Honda,
Nissan, and Toyota in making head-protecting side
airbags standard in their minivans. Important
safety equipment like this shouldn't be optional."
The good performers also have side structures
that resist major intrusion into the occupant
compartment.
MPV and Freestar without side airbags are poor:
In the test, the driver dummy's head was struck
by the intruding barrier. This didn't produce
high injury measures, but head hits with intruding
objects such as other vehicles, trees, or poles
should be prevented.
"Plus the MPV's structure was marginal, so
there was more intrusion that contributed to high
forces on other parts of the dummies," Lund
said. "In a crash of similar severity
in the real world, it's likely that a driver would
suffer internal organ injuries as well as rib
fractures. The rear passenger possibly would sustain
a fractured pelvis."
In the Freestar without side airbags, the barrier
came close to hitting the driver dummy's head.
This indicates that only slightly different crash
circumstances could produce a direct hit to a
person's head. The Freestar's structure also is
poor, which in the absence of optional side airbags
contributed to high forces on the driver dummy's
chest.
Side airbags reduce risks in real-world crashes —
Almost 10,000 passenger vehicle occupants die
each year in side impacts, and head injuries are
a leading cause. Institute research shows that
side airbags with head protection are reducing
deaths by about 45 percent among drivers of cars
struck on the driver side. Before the availability
of head-protecting airbags, there was virtually
nothing to prevent people's heads from being struck
by intruding vehicles or rigid objects like trees
or poles in serious side impacts. Side airbags
that protect the chest and abdomen, but not the
head, also are reducing deaths but are less effective
(about a 10 percent reduction in deaths).
How vehicles are evaluated: The Institute's frontal
crashworthiness evaluations are based on results
of frontal offset crash tests at 40 mph. Each
vehicle's overall evaluation is based on three
aspects of performance — measurements of intrusion
into the occupant compartment, injury measures
from a Hybrid III dummy positioned in the driver
seat, and analysis of slow-motion film to assess
how well the restraint system controlled dummy
movement.
Each vehicle's overall side evaluation is based
on injury measures recorded on two instrumented
SID-IIs dummies, assessment of head protection
countermeasures, and the vehicle's structural
performance during the impact. Injury measures
obtained from the two dummies, one in the driver
seat and the other in the rear seat behind the
driver, are used to determine the likelihood that
a driver and/ or passenger in a real-world crash
would have sustained serious injury to various
body regions.
The movements and contacts of the
dummies' heads during the crash also are evaluated.
This assessment is more important for seating
positions without head-protecting airbags which,
assuming they perform as intended, should prevent
injurious head contacts. Structural performance
is based on measurements indicating the amount
of B-pillar intrusion into the occupant compartment.
Some intrusion into the compartment is inevitable
in serious side impacts, but any intrusion that
does occur should be uniform both horizontally
and vertically and shouldn't seriously compromise
the driver or passenger space. |