Curtain airbags are designed to protect the driver and passengers in a crash. Without them in a side impact crash there is little to protect your body and head from striking the side of the car or rigid objects like trees or poles. The curtain airbag activates instantaneously in the event of a side impact crash deploying from the top of the door rails above the side window. They form a cushion for the driver or passengers and stay in place if the car rolls over to protect their heads.
Curtain airbags, which drop down from the roof along both sides of the cabin, give better protection to the occupants of a vehicle as they cover most of the glass area. They also help protect passengers seated in the rear of a car.