The WHIPS head restraint system – fitted as standard in all Volvo cars – has halved the risk of long-term neck injuries in rear-end impacts. The next stage for Volvo Car Corporation is to provide the same protection in frontal and side impacts too.
One of the people who have carried out in-depth studies of the factors that increase injury risks is Lotta Jakobsson, biomechanics expert at Volvo Cars and a doctoral candidate on the technical aspects of traffic safety: “It’s all about pursuing the development of products that really do serve to offer protection in real-life situations,” she explains.
Neck injuries constitute the most common traffic injury, and in Sweden alone 25,000 people are affected every year. About one in every ten suffers long-term neck-related problems, which are often difficult to diagnose accurately. Lotta Jakobsson’s doctoral thesis spotlights the factors that increase the risk of injury and it also offers guidelines for the development of protection systems since the pattern of injury is not definitive.
WHIPS – reducing injuries since 1998
This research method lies behind the development and evaluation of Volvo Cars’ WHIPS safety system, which was launched in 1998 and which today is fitted as standard in all Volvo cars. By combining analyses of actual collisions with advanced computer simulations, Lotta Jakobsson has studied the movement patterns of the car occupant’s neck in a variety of situations.
“We must know how we want the neck to move in order to provide the best protection for it. What is best documented is that a rear-end impact constitutes the greatest risk of neck injury,” says Lotta Jakobsson, adding that there is a risk of neck injury in all accident scenarios since frontal collisions are more than twice as common. That is why the number of injuries is comparable with those sustained in rear-end impacts.
Greater risk of injury – and better protection
Her dissertation highlights factors that increase the risk of injury in both frontal collisions and rear-end impacts. What is more, analyses of actual accidents show that several factors affect the risk of injury as much as the actual force of the collision itself – factors such as gender, age, height, body weight and seating position. “A person’s general bodily condition can actually play a significant part. Previous neck problems influence the risk of injury, and several studies show that a stressful lifestyle affects the healing process,” she continues.
When the WHIPS car seat was developed, it was a foregone conclusion that it would reduce the number of neck injuries, but nobody knew just how effective it would be.
In the evaluation, the seat is compared with its predecessors in the Volvo S40/V40 and Volvo S70/V70. Calculations show that WHIPS reduces the incidence of neck-related problems immediately after a crash by 33 percent. The incidence of neck pain lasting more than one year is reduced by 53 percent.
At the age of 22 in 1989, Lotta Jakobsson came to Volvo Cars as a graduate engineer, straight after her studies at the Chalmers University of Technology in Göteborg, Sweden. In 1991, she graduated in biomechanics in the field of safety, and she was recently appointed technical specialist at Volvo Cars.
On Friday 27 February, Lotta Jakobsson returns to Chalmers to defend her dissertation entitled “Whiplash Associated Disorders in Frontal and Rear-End Impacts: Biomechanical Guidelines and Evaluation Criteria Based on Accident Data and Occupant Modeling.” She worked on her dissertation at the university’s Faculty of Mechanical and Vehicle Systems.