How do airbags work and why are they important for car safety?

“airbag” by Ben McLeod is licensed under CC BY-NC-SA 2.0

During a collision, airbags are inflated cushions fitted into a car that protect occupants from hitting the vehicle interior or objects outside the vehicle (for example, other automobiles or trees). Sensors begin measuring impact severity the moment a crash occurs. If the impact is hard enough, the sensors activate inflators, which fill the bags with gas in a fraction of a second. Unless they deploy in a crash, airbags rarely require maintenance. In that scenario, they must be replaced at a repair facility that uses genuine original equipment manufacturer (OEM) replacement parts to verify that the new airbag is not a forgery. Counterfeit airbags may not deploy or may emit metal shards during a crash. Front airbags are intended to inflate in moderate to severe frontal collisions in order to keep a person’s head and chest from colliding with hard components in the car. They provide maximum protection when occupants wear safety belts and sit properly in the seat, but they are designed to protect all occupants. Newer airbags include a safety belt sensor and utilize an algorithm to determine whether or not to deploy the bag in a specific crash based on whether or not occupants are wearing safety belts. 

The federal government has required automakers to add driver and passenger airbags for frontal crash protection in all cars, light trucks, and vans since the 1999 model year. Some manufacturers include lower-mounted knee airbags as an option. Knee airbags are designed to disperse impact forces and thereby decrease leg injuries. They may also help lessen stresses on an occupant’s chest and abdomen by limiting the occupant’s lower body movement. A collision study in Australia discovered that side airbags with head and torso protection lower a car driver’s risk of death or injury in driver-side crashes by 41%. An NHTSA research focusing on the fatality risk to drivers and right-front-seat passenger cars engaged in nearside incidents discovered similar trends. Curtain and torso airbags combined reduce the chance of mortality by 31%, and combination head/torso airbags reduce the risk by 25%. The fatality decrease was smaller in vehicles that just had a curtain airbag (16%) or a torso airbag (16%). The results of the IIHS side crash testing demonstrate the critical significance of head-protecting side airbags. Since the program’s inception in 2003, every car that has received a good rating has had side airbags that protect the head. However, airbags alone are insufficient. Vehicles also require side structures that can withstand significant penetration into the occupant compartment.

If weight sensors detect a small driver, front-seat passenger, or kid safety seat, advanced airbags alter deployment patterns. Manufacturers must pass a battery of tests that include belted and unbelted dummies in a variety of crash test speeds and configurations. People can potentially be injured by faulty airbags. The government initiates recalls for vehicles that have malfunctioning airbag systems, which increase the chance of injuries in a crash. Failure to deploy, wrong timing or energy of deployments, and malfunctioning parts are all possible causes. Recalled airbags should be replaced to ensure that occupants receive the best possible protection in the event of a crash. The Takata airbag recall, which began in 2015, is the largest in US history, with an anticipated 70 million vehicles recalled by 2019. The issue that triggered the recall has been linked to 15 verified deaths in the United States and over 250 documented injuries.