27 June 2001: GM is to make full-size curtain airbags available on its Opel Corsa, Astra and Zafira models from the autumn.

The curtain airbags on both sides of the car provide front and rear passengers with added protection in a side collision. They inflate like a curtain along the side window area within 25 to 30 milliseconds, so cushioning the heads of the occupants from the effects of a lateral impact and significantly cutting the risk of injury from shattered glass.

The curtain airbags have a fully-inflated volume of around 25 litres. The anchor points at the front and rear ends of the airbags are set as low as possible, to ensure the airbags are fully effective regardless of the occupants' seating position.

The airbag system is fitted in a plastic tube along the full length of the headliner (Zafira: first and second seating rows), and the gas inflation generator is in the rear section of the headliner.

Both curtain and side airbags are controlled by a single control device which is triggered by sensors integrated in the sides of the vehicle.

In a typical lateral impact, the side airbag deploys first, within 10 milliseconds, to protect the chest, and 10 to 15 milliseconds later, the head is cushioned by the 150 millimetre thick curtain of air.

The curtain airbags considerably reduce the force of the impact on the passengers, especially if the side of the vehicle collides with a post or tree. In tests carried out using NCAP criteria, the car is propelled sideways at 18mph into a rigid pole, and the risk of head injury is reduced by around 90 per cent. TW