Airbags are positioned in the steering wheel and, on most cars, in the passenger side of the dashboard as well. Airbags prevent the driver and/or passenger from striking the steering wheel, dashboard or windshield in the event of a frontal collision. Found in the seat, side pillars or doors, side airbags are beginning to appear as manufacturers strive to increase side-impact protection. Airbags are not substitutes for seat belts, which is why they are called a Supplemental Restraint System (SRS).
Pros
Airbags have been proven to reduce the severity of injuries in head-on collisions.
Cons
They're expensive to replace after they've been deployed.