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In an American test of whiplash protection systems in SUVs and pickups, the
Volvo XC90 is one of few models to achieve the top rating.
An independent American research and safety institute, the IIHS (Insurance
Institute For Highway Safety) used a crash test dummy to register loads on the
neck during a simulated impact from the rear. This is the first time the IIHS
has carried out a dynamic test with SUVs and pickup trucks.
The test was carried out in two stages. First, the seats were measured to
determine the head restraint’s geometry and to determine the preconditions for
protecting the head of a man of normal height.
Only seats with good or acceptable head restraint geometry proceeded to the
second stage, the dynamic crash test. Here, a moving platform was used to
simulate a situation where a car standing still was hit from behind by a vehicle
of the same weight driving at 20mph (about 32km/h).
The test method and the evaluation criteria have been developed within the
framework of broad international cooperation between experts in preventive
whiplash injuries (IIWPG – International Insurance Whiplash Prevention Group).
Only six of the 44 vehicles tested proved to offer effective protection
against whiplash injuries. The Volvo XC90 is one of the best. The overall
assessment includes both the seats’ measured geometry and the results of the
dynamic test.
The IIHS emphasises that effective protection against whiplash injuries is an
important factor for reducing both human suffering and the cost of
rehabilitation. Collisions from behind are very common and neck injuries are the
most common type of serious injury arising from car accidents.
The Movement of the Head and Upper Body Must Be Synchronised
According to the IIHS, the key to effective protection is that the seat
occupant’s head and upper body should move in harmony during the collision
sequence. Whiplash injuries are usually caused by the head not keep up with the
body as it jerks forward under the force of the impact. For this reason, the
seat and head restraint must interact to support the head so that it accelerates
together with the upper body.
It is also important that the head restraint is sufficiently high and
positioned close to the head. “Volvo’s head restraint is designed in precisely
this way,” explains Ingrid Skogsmo, Director of the Volvo Cars Safety Centre.
“WHIPS, Volvo’s Whiplash Protection System that is fitted as standard in all new
Volvo cars, is designed in such a way that it ensures that both the head and
torso move together, and also that acceleration forces are limited.”
Volvo’s advanced whiplash protection design is one of the reasons behind the
excellent test results, and this is confirmed by the IIHS.
Volvo’s Whiplash Protection System (WHIPS)
In Volvo’s Whiplash
Protection System, the front seats and their headrests are designed to provide
uniform support for the entire back and head during the collision sequence. In
addition, a bracket fitted between the seat backrest and the seat cushion helps
the seat to absorb the incoming energy, thus reducing the acceleration forces in
a rear-end impact.
This is done by the weight of the occupant’s body pressing the backrest
rearward in a simultaneous horizontal and reclining position. This motion
dampens the incoming forces rather like when a person catches a thrown ball,
thus reducing the stress exerted on the occupant’s body. It also reduces the
subsequent forward motion.
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