Airbags Skip to content Vehicle ratings News Research areas About Home Research areas Airbags Home Research areas Airbags Airbags Overview How front and side airbags work Lives saved by airbags Airbag injuries Airbag innovations Overview The information on this page was compiled by Becky Mueller, a senior research engineer at IIHS. Becky studies crash injury trends and develops new crash tests for IIHS ratings. Contact Becky. Airbags are one of the most important safety innovations of recent decades. Normally hidden, they inflate instantly to provide crucial cushioning for vehicle occupants when a crash occurs. Both front and side airbags substantially reduce fatality risk. Front airbags have been required in all new passenger vehicles since the 1999 model year. Side airbags aren’t specifically mandated, but nearly all manufacturers include them to meet federal side protection requirements. Engineers keep finding new ways to use airbags. Rear-window curtain airbags are designed to protect people in back seats in rear-end crashes. Far-side airbags keep drivers and front-seat passengers from hitting each other in a crash. Inflatable safety belts are aimed at reducing rear-seat chest injuries. How front and side airbags work Airbags are inflatable cushions built into a vehicle that protect occupants from hitting the vehicle interior or objects outside the vehicle (for example, other vehicles or trees) during a collision. The instant a crash begins, sensors start to measure impact severity. If the crash is severe enough, the sensors signal inflators to fill the bags with gas in a fraction of a second. Airbags don’t typically require maintenance unless they deploy in a crash. In that case, they must be replaced at a repair shop that uses original equipment manufacturer (OEM) replacement parts to ensure that the new airbag is not counterfeit. Counterfeit airbags may fail to deploy or release metal shrapnel during deployment. Front airbags Since the 1999 model year, the federal government has required automakers to install driver and passenger airbags for frontal impact protection in all cars, light trucks and vans. Front airbags are designed to inflate in moderate-to-severe frontal crashes to prevent a person’s head and chest from contacting hard structures in the vehicle. They offer the most protection when occupants are wearing safety belts and sitting properly in the seat but are designed to provide protection for all occupants. Newer airbags have a safety belt sensor and use an algorithm to decide whether to deploy the bag in a given crash, depending on whether people are using safety belts. For unbelted occupants, a front airbag will typically deploy when the crash is the equivalent of an impact into a rigid wall at 10-12 mph. For belted occupants, most airbags will deploy at a higher threshold — about 16 mph — because the belts alone are likely to provide adequate protection up to these moderate speeds. Front airbags may deploy to help protect occupants in side impacts if there is sufficient forward movement during the crash. The driver airbag is located in the steering wheel. The passenger airbag is located in the dashboard. Front dual airbag system Knee airbag (BMW) Some manufacturers provide supplemental knee airbags, mounted lower. Knee airbags are intended to distribute impact forces to reduce leg injuries. They may also help reduce forces on an occupant’s chest and abdomen by controlling movement of the occupant’s lower body. Side airbags Head- and chest-protecting side airbags are designed to inflate in side crashes to prevent people’s heads and chests from contacting intruding parts of vehicle side structure, a striking vehicle or an object such as a tree or pole. Side airbags cushion and spread the load of impacts to prevent any part of the body from sustaining concentrated impact forces. A head-protecting side airbag is particularly important because it may be the only thing between the occupant’s head and the striking vehicle, since window glass can shatter in a crash. Because of the small space between an occupant and the side of the vehicle, side airbags must deploy very quickly, typically within the first 10-20 milliseconds of a side crash. Deployment thresholds can be as low as 8 mph for narrow object crashes (e.g., trees and poles) and 18 mph for the more widely distributed side impacts (vehicle-to-vehicle crashes). Side airbags also deploy in certain types of frontal crashes. A federal regulation on side-impact protection requires a certain level of head and torso protection for all occupants. While it doesn’t specifically mandate side airbags, the required protection is typically achieved with them. As of the 2014 model year, virtually all new passenger vehicles must comply with this regulation. As a result, the vast majority of passenger vehicles come with side airbags as standard equipment. A head-protecting curtain airbag is often the only barrier between the dummy’s head and the striking vehicle. Different types of side airbag systems A combination airbag, deploying from the seatback, provides protection for the head and torso. A head-protecting curtain airbag, which deploys from the roof rail, and a seat-mounted torso-protecting airbag A head-protecting curtain airbag and a seat-mounted torso- and pelvis-protecting airbag A head-protecting curtain airbag deploying from the door and seat-mounted torso and pelvis-protecting airbag Rollover deployment of side airbags Side curtain airbags can be designed to deploy in a rollover crash. Sensors that measure a vehicle’s sideways movement and tilting can detect if a rollover is about to occur, triggering deployment. These airbags typically inflate within the first 10-20 milliseconds of a rollover crash and can remain inflated longer than regular side curtain airbags (10 or more seconds) to protect during multiple-roll crashes. They typically cover the window opening and inflate more stiffly to prevent ejection of the occupant. The government doesn’t specifically require side curtain airbags with this capability, but automakers have been using them to meet a requirement that all 2018 or newer vehicles prevent occupant ejection through side windows. A side curtain airbag used to meet the federal safety standard to prevent occupant ejection remains inflated for more than 10 seconds, covering multiple rolls of the vehicle, and keeps occupants contained inside. Lives saved by airbags Numerous studies have confirmed the effectiveness of airbags in preventing death and injury, especially in combination with seat belts (Viano, 2024). NHTSA estimates that 4,330 lives were saved by frontal airbags in 2019 alone (Kahane & Simons, 2024). In total, 70,059 lives have been saved by frontal airbags through that year. In frontal crashes, front airbags reduce driver fatalities by 29% and fatalities of front-seat passengers age 13 and older by 32% (Kahane, 2015). NHTSA estimates that the combination of an airbag plus a lap and shoulder belt reduces the risk of death in frontal crashes by 61%, compared with a 50% reduction for belts alone and a 34% reduction for airbags alone. NHTSA estimates that as of 2012, 2,252 lives have been saved by side airbags (Kahane, 2015). Side airbags with head protection reduce a car driver’s risk of death in driver-side crashes by 37% and an SUV driver’s risk by 52% (McCartt & Kyrychenko, 2007). A subsequent NHTSA study focusing on the fatality risk to drivers and front-seat passengers involved in nearside crashes found that curtain airbags and torso airbags together reduce the risk of death by 31%, and combination head/torso airbags reduce the risk by 25% (Kahane, 2014). The crucial role played by head-protecting side airbags is illustrated by the results of IIHS side crash tests. Since the program began in 2003, all the vehicles earning good ratings have been equipped with side airbags that protect the head. However, airbags alone aren’t enough. Vehicles also need side structures that resist major intrusion into the occupant compartment. Airbag injuries Occasionally, the energy required to quickly inflate airbags can cause injury to people sitting or thrown too close to the airbag before it deploys. This was a serious concern with the first generations of frontal airbags, which deployed with greater force. NHTSA estimates that during 1990-2008, more than 290 deaths were caused by frontal airbag inflation in low-speed crashes (NHTSA, 2017). Nearly 90% of the deaths occurred in vehicles manufactured before 1998, and more than 80% of people killed were unbelted or improperly restrained. Most of the deaths were passengers, and more than 90% of those were children and infants, most of whom were unbelted or in rear-facing child safety seats that placed their heads close to the deploying airbag. Short and elderly drivers, who tend to sit close to the steering wheel, also were vulnerable to inflation injuries from frontal airbags. Today, thanks to changes in government requirements, serious injuries from properly functioning airbags are rare. The changes came in two phases. In the first, federal rules were modified to encourage automakers to reduce the energy in front airbags. Depowering began with 1998 models. Later, NHTSA issued a certified-advanced airbag rule that required more sophisticated airbags in all passenger vehicles by the 2007 model year. Advanced airbags modify deployment patterns if weight sensors detect a small driver or front-seat passenger or a child safety seat. Manufacturers must pass a suite of tests using different-size dummies, belted and unbelted, in a variety of crash test speeds and configurations. Side airbags also can deploy with enough energy to cause injury, although they typically are smaller and deploy with less energy than frontal airbags. Injuries from contact with side airbag inflations in crashes have been documented (Kahane, 2015), but there is no indication that such injuries are common. A field study of children in side crashes found no increased risk of injury to children age 15 and younger associated with side airbag deployment (Arbogast & Kallan, 2007). Faulty airbags also can injure people. The government issues recalls for vehicles with faulty airbag systems that result in increased risk of injury in a crash. Reasons can include failure to deploy, incorrect timing or energy of deployments, and defective parts. Recalled airbags should be replaced to ensure that occupants receive the optimal level of protection in a crash. Consumers can find information on recalls affecting their vehicles in the NHTSA recall database. The database also has information on service centers that are authorized to repair recalled vehicles free of charge. The Takata airbag recall, which began in 2015, is the largest recall in U.S. history, with an estimated 67 million vehicles recalled by 2022. Of that number, 6 million have yet to have their airbags replaced. The problem that prompted the recall has been tied to 23 confirmed deaths in the U.S. and more than 250 reported injuries. What can occupants do to prevent injuries from airbags? Drivers and front-seat passengers should sit in the center of the seat upright against the seatback with feet on the floor. Arms and legs should never be resting against an airbag because the forces of a deploying airbag and the hot gases exhausted by the airbag may cause injury. Avoid aftermarket dash or seat covers, which can block or redirect a deploying airbag. Drivers should sit with their chests at least 10 inches away from the center of the steering wheel. Shorter drivers who need the seat positioned further forward can often achieve this by slightly reclining the seatback. Many newer airbags take into account seat position and deploy with less force if an occupant is sitting close. For drivers of older vehicles who cannot get far enough away from the steering wheel, pedal extenders or an airbag on-off swi…