Pregnant dummy from Volvo, curtain airbags from Honda

These days, everyone on board a car is protected by comprehensive safety systems. Everyone – except the unborn child. Researchers still know very little about what happens to fetuses during car accidents.

To shed more light on this area, Volvo Car Corporation has developed the world’s first official computer model of a pregnant crash dummy.

"Now we’ve covered the whole lifecycle," says Camilla Palmertz, a biomechanical engineer at the Volvo Cars Safety Center. "One big advantage is that both mother and baby can be scaled up or down to the size we want to study."

This virtual crash dummy is a woman at a late stage of her pregnancy, since that is when the unborn baby is at greatest risk during an accident. The basic design had been completed by January. Since then much time has been devoted to refining the model.

"Now it’s finished and we’ve started running simulated front-end impact tests on it," Palmertz said.

The purpose of the tests is to study how the virtual mother-to-be and her unborn baby are affected by the seatbelt and airbag in simulated accidents. The computer model makes it possible to study in great deal how the belt moves, the influence of the belt and airbag on the uterus, placenta and fetus, and how the fetus moves in relation to the mother’s body. Among other things, the model can also be used to test new designs for seat belts and other safety systems.

"I’m certain that there’s room for further development of the three-point belt, to make it more comfortable and to provide even better protection," said Palmertz.

Today many pregnant women worry whether the seat belt could harm their unborn baby if they are involved in a car accident. Researchers all agree, however, in recommending that they should always wear their seatbelt.

In an accident, the pregnant woman’s thorax and pelvis are both restrained by the belt, but her abdomen is free to move in the direction determined by the particular forces arising from the impact. Because the fetus is floating free inside her, injuries tend to fall into two main types. The more common of the two is that the placenta becomes either partially or completely detached, which means that the baby cannot get enough oxygen. The rarer scenario is for the head of the baby to be injured if it hits one of the bones of the mother’s pelvis.

Curtain Airbag

Meanwhile, Honda is introducing a new, rapidly deploying side curtain airbag that protects vehicle occupants from head and neck injuries in the event of a side collision. The side curtain airbag deploys over a wide area to protect both front and rear seat occupants, especially from head impacts to the center pillar. The first Honda to be equipped with the new airbag system will be the new 2003 Accord.

The new side curtain airbag is the latest product of Honda’s airbag philosophy. In order to deploy the airbag to cover almost the entire window surface instantaneously, the airbag is fitted with a low-temperature gas (compressed helium) inflator that achieves a deployment speed of approximately 0.015sec. This rapid deployment speed allows the bag to be made thicker for more effective impact absorption, reducing the shock to the head area at time of impact.

The system uses five impact sensors located in the middle of the vehicle and beside the left and right front seat occupants, along with sensors positioned next to the rear seat occupants.

Honda first began basic airbag research in 1971. In 1987, it was the first Japanese auto maker to introduce a driver-side supplemental restraint system (SRS) airbag system. In 1998, the same thinking was further applied to Honda’s SRS system, featuring an inflator with a two-stage deployment system depending on the size of the impact, and a side airbag with an occupant posture detection sensor that combined improved occupant protection with reduced risk of collateral injury – both world firsts.