A car traveling at 60 mph has a great deal of momentum. All of the passengers in the car are moving at 60 mph also. If the car has a head-on collision and the car's speed drops to zero within a matter of a second or so, the passengers are still moving at 60 mph and, without some kind of restraint, will continue traveling at 60 mph until they are stopped. What's to stop them? The steering wheel of the car or the windshield are the most likely places with a head-on collision. Many passengers travel THROUGH the windshield in those circumstances and land in the aftermath of what's left of the mangled pieces. A seat belt is a good restraint for the torso (I had that happen to me and the seat belt broke a rib BUT I wasn't thrown through the windshield); but an airbag is good to keep the head from being forced down and into the steering wheel (or worse yet having the steering wheel forced into the head). Both seat belts and airbags are very good saftey devices. Side airbags are being installed in some cars now to help provide safety for cars involved in other than head-on collisions.
