View source for Airbag

{{Short description|Vehicle safety device}}
{{About|a car safety device}}
{{Use dmy dates|date=December 2019}}
[[File:Peugeot 306 airbags deployed.jpg|thumb|upright=1.35|The driver and passenger front airbag modules, after having been deployed, in a [[Peugeot 306]]]]

An '''airbag''' or '''supplemental inflatable restraint'''<ref>{{Cite book |last1=Hendrix |first1=T.D. |last2=Kelley |first2=J.P. |last3=Piper |first3=W.L. |chapter=Mechanical Versus Accelerometer Based Sensing for Supplemental Inflatable Restraint Systems |date=1990 |title=Vehicle Electronics in the 90's: Proceedings of the International Congress on Transportation Electronics |pages=13–22 |doi=10.1109/ICTE.1990.712994 |isbn=1-56091-047-X }}</ref> is a vehicle occupant-restraint system using a bag designed to inflate in milliseconds during a [[Traffic collision|collision]] and then deflate afterwards.<ref>{{cite web|url= https://www.iihs.org/topics/airbags |title=Airbags |work=Insurance Institute for Highway Safety (IIHS) |access-date=7 March 2024}}</ref> It consists of an airbag cushion, a flexible fabric bag, an inflation module, and an impact sensor. The purpose of the airbag is to provide a vehicle occupant with soft cushioning and restraint during a collision. It can reduce injuries between the flailing occupant and the vehicle's interior.

The airbag provides an energy-absorbing surface between the vehicle's occupants and a steering wheel, instrument panel, [[Pillar (car)|body pillar]], headliner, and [[windshield]]. Modern [[vehicle]]s may contain up to ten airbag modules in various configurations, including driver, passenger, side-curtain, seat-mounted, door-mounted, B- and C-pillar mounted side-impact, knee bolster, inflatable seat belt, and pedestrian airbag modules.<ref>{{cite web|last=Varela |first=Kristin |title=How Many Airbags Are Enough? |url= https://www.cars.com/articles/2013/06/how-many-airbags-are-enough/ |website=cars.com |access-date=14 November 2017 |date=19 June 2013 |url-status=live|archive-url= https://web.archive.org/web/20171115082931/https://www.cars.com/articles/2013/06/how-many-airbags-are-enough/ |archive-date=15 November 2017}}</ref>

During a crash, the vehicle's crash sensors provide crucial information to the airbag electronic controller unit (ECU), including collision type, angle, and severity of impact. Using this information, the airbag ECU's crash algorithm determines if the crash event meets the criteria for deployment and triggers various firing circuits to deploy one or more airbag modules within the vehicle. Airbag module deployments are activated through a [[Pyrotechnics|pyrotechnic]] process designed to be used once as a supplemental restraint system for the vehicle's seat belt systems. Newer side-impact airbag modules consist of compressed-air cylinders that are triggered in the event of a side-on vehicle impact.<ref>{{cite web |title=The Global Automotive Airbag Market Outlook |publisher=Valient Automotive Market Research |url= http://valientmarketresearch.com/industries/automotive/airbag/ |url-status=usurped |archive-url= https://web.archive.org/web/20150623025953/http://valientmarketresearch.com/industries/automotive/airbag/ |archive-date=23 June 2015 |access-date=7 March 2024}}</ref>

The first commercial designs were introduced in passenger automobiles during the 1970s. These designs saw limited success and caused some fatalities.<ref>{{cite news|url= https://www.thoughtco.com/history-of-airbags-1991232 |title=Who Invented Airbags?|work=ThoughtCo |first=Mary |last=Bellis |date=9 August 2019 |access-date=15 January 2020}}</ref> Broad commercial adoption of airbags occurred in many markets during the late 1980s and early 1990s.

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== Active vs. passive safety ==
Airbags are considered "passive" restraints and act as a supplement to "active" restraints. Because no action by a vehicle occupant is required to activate or use the airbag, it is considered a "passive" device. This is in contrast to [[seat belt]]s, which are considered "active" devices because the vehicle occupant must act to enable them.<ref>{{cite journal|first=Kenneth E. |last=Warner |title=Bags, Buckles, and Belts: The Debate over Mandatory Passive Restraints in Automobiles |doi=10.1215/03616878-8-1-44 |pmid=6863874 |journal=Journal of Health Politics, Policy and Law |year=1983 |volume=8 |issue=1 |pages=44–75 }}</ref><ref>{{cite web|url= http://www.motorvista.com/airhist.htm |archive-url= https://web.archive.org/web/20010222142601/http://motorvista.com/airhist.htm |url-status= dead |archive-date= 22 February 2001 |title=U.S. air bag history |website=motorvista.com |year=2000 |access-date=16 March 2014 }}</ref><ref>{{cite web|url= http://www.patentstorm.us/patents/6272412/description.html |title=U.S. patent 6272412 – Passive restraint control system for vehicles |website=patentstorm.us |access-date=17 October 2010 |url-status=dead |archive-url= https://web.archive.org/web/20110612202945/http://www.patentstorm.us/patents/6272412/description.html |archive-date=12 June 2011}}</ref><ref>{{cite web |url= http://www.dfs.ny.gov/insurance/circltr/1991/cl1991_10.htm |title=Circular Letter No. 10 (1991): Auto Insurance Premium Discounts For Passive Restraints |publisher=New York State Department of Financial Services |date=12 April 1991 |access-date=16 March 2014 |url-status=dead |archive-url= https://web.archive.org/web/20140316220229/http://www.dfs.ny.gov/insurance/circltr/1991/cl1991_10.htm |archive-date=16 March 2014 }}</ref>

This terminology is not related to [[Automobile safety#Active and passive safety|active and passive safety]], which are, respectively, systems designed to prevent collisions in the first place, and systems designed to minimize the effects of collisions once they occur. In this use, a car [[Anti-lock braking system]] qualifies as an active-safety device, while both its seat belts and airbags qualify as passive-safety devices. Terminological confusion can arise from the fact that passive devices and systems—those requiring no input or action by the vehicle occupant—can operate independently in an active manner; an airbag is one such device. Vehicle safety professionals are generally careful in their use of language to avoid this sort of confusion. However, [[advertising]] principles sometimes prevent such [[Semantics|semantic]] caution in the consumer marketing of safety features. Further confusing the terminology, the [[aviation safety]] community uses the terms "active" and "passive" in the ''opposite'' sense from the automotive industry.<ref>[https://vtol.org/store/templates/product/createPreview.cfm Rotorcraft Active Crash Protection Systems] {{webarchive|url= https://web.archive.org/web/20170623160112/https://vtol.org/store/templates/product/createPreview.cfm |date=23 June 2017}}</ref>

== History ==
[[File:Round &amp; Parrott blue plaque unveiling - Andy Mabbett - 2019-03-18 - 05.jpg|thumb|upright=0.9| [[Blue plaque]] commemorating Round and Parrott's patent, at [[Birmingham Dental Hospital]] ]]
[[File:Original Airbag Design Blueprint 1953.png|thumb|upright|John W. Hetrick's 1953 safety cushion patent drawing<ref>{{cite patent|title=Safety cushion assembly for automotive vehicles |pubdate=18 August 1953 |country=US |number=2649311 |inventor1-first=John W. |inventor1-last=Hetrick |inventor1-link=John_W._Hetrick}}</ref>]]
[[File:Interior of 1975 Buick Electra.jpg|thumb|1975 [[Buick Electra]] with ACRS]]
[[File:Vauxhall Vectra curtain airbag deployed.jpg|thumb|A deployed curtain airbag in an [[Opel Vectra]]]]

=== Origins ===
The airbag "for the covering of aeroplane and other vehicle parts" traces its origins to a United States patent, submitted in 1919 by two dentists from [[Birmingham]], Arthur Parrott and Harold Round.<ref name="BDH">{{cite web |title=University of Birmingham to unveil new 'blue plaque' celebrating the work of two innovative dentists |url= https://www.birmingham.ac.uk/university/colleges/mds/news/2019/03/dentistry-blue-plaque.aspx |publisher=Birmingham Dental Hospital |access-date=18 March 2019 |date=13 March 2019}}</ref> The patent was approved in 1920.<ref>{{cite patent |country=US |number=1331359 |inventor2-first=Harold |inventor2-last=Round |inventor1-first=Arthur Hughes|inventor1-last=Parrott |pubdate=17 February 1920 |assign=[[Robert Davis (inventor)|Robert Henry Davis]]}}</ref> Air-filled bladders were in use as early as 1951.<ref>{{cite book|chapter-url= https://books.google.com/books?id=bBDKTa4abNwC&pg=PA12|page=12 |title=Innovative Materials and Techniques in Concrete Construction: ACES Workshop |editor-first=Michael N. |editor-last=Fardis |chapter=1 Non Finito: challenges in rehabilitation |first=Urs |last=Meier |publisher=Springer |year=2012 |isbn=9789400719965 |access-date=16 March 2014}}</ref><ref>{{cite web|title=Air Bags for Automobiles |url= https://textilelearner.net/airbag-for-automobiles/ |work=Textile Learner |first=Moin.S |last=Khan |date= 10 September 2012 |archive-url= https://web.archive.org/web/20121118075037/http://textilelearner.blogspot.com/2012/09/air-bags-for-automobiles-materials-and.html |archive-date=18 November 2012 |access-date=22 September 2016}}</ref> The airbag specifically for automobile use is credited independently to the American [[John W. Hetrick]], who filed for an airbag patent on 5 August 1952, that was granted #2,649,311 by the United States Patent Office on 18 August 1953.<ref>{{cite book|url= https://books.google.com/books?id=kXP6AQAAQBAJ&pg=PA1613|page=1613 |title=Road and Off-Road Vehicle System Dynamics Handbook |year=2014 |publisher=CRC Press |editor-first=Giampiero |editor-last=Mastinu |editor-first2=Manfred |editor-last2=Ploechl |isbn=9780849333224 |access-date=22 September 2016}}</ref><ref>{{cite web|title=United States Patent #2649311|publisher=United States Patent and Trademark Office |url= http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&p=1&u=/netahtml/PTO/srchnum.html&r=1&f=G&l=50&d=PALL&s1=2649311.PN.|access-date=15 March 2021}}</ref><ref>{{cite web|title=Patent Images|url= https://pdfpiw.uspto.gov/.piw?Docid=02649311&homeurl=http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1%2526Sect2=HITOFF%2526p=1%2526u=/netahtml/PTO/srchnum.html%2526r=1%2526f=G%2526l=50%2526d=PALL%2526s1=2649311.PN.%2526OS=%2526RS=&PageNum=&Rtype=&SectionNum=&idkey=NONE&Input=View+first+page|access-date=15 March 2021 |website=pdfpiw.uspto.gov}}</ref> German patent #896,312 filed for by engineer Walter Linderer on 6 October 1951 was issued on 12 November 1953, approximately three months after American John Hetrick. The airbags proposed by Hetrick and Linderer were based on compressed air released by a spring, bumper contact, or by the driver. Later research during the 1960s showed that compressed air could not inflate the mechanical airbags fast enough to ensure maximum safety, leading to the current chemical and electrical airbags.<ref>{{cite web |title=The History of Airbags |date=19 April 2017 |work=The Thought Company |url= https://www.thoughtco.com/history-of-airbags-1991232 |first=Mary |last=Bellis |access-date=22 September 2016 |url-status=dead |archive-url= https://web.archive.org/web/20170714234135/https://www.thoughtco.com/history-of-airbags-1991232 |archive-date=14 July 2017 }}</ref><ref name="Big Ideas">{{cite book|first= Alex |last=Hutchinson |title=Big Ideas: 100 Modern Inventions That Have Transformed Our World |publisher=Sterling Publishing |url= https://books.google.com/books?id=FtN7DIvmmF4C&pg=PA136|page=136 |isbn=9781588167224 |year=2009 |access-date=22 September 2016}}</ref> In patent applications, manufacturers sometimes use the term "inflatable occupant restraint systems".

Hetrick was an [[Industrial engineering|industrial engineer]] and member of the [[United States Navy]]. His airbag design, however, only came about when he combined his experiences working with navy [[torpedo]]es with his desire to protect his family on the road. Despite working with the major automobile manufacturers of his time, Hetrick was unable to attract investment.<ref>{{cite web|url= http://www.airbagsolutions.com/history2.aspx |title=Airbag History – When Was The Airbag Invented? |website=airbagsolutions.com |access-date=16 March 2014 |url-status=dead |archive-url= https://web.archive.org/web/20140316195436/http://www.airbagsolutions.com/history2.aspx |archive-date=16 March 2014}}</ref><ref>{{cite web |url=http://inventors.about.com/od/astartinventions/a/air_bags.htm |title=The History of Airbags |website=inventors.about.com |access-date=16 March 2014|archive-url=https://archive.today/20120722020108/http://inventors.about.com/od/astartinventions/a/air_bags.htm|archive-date= 22 July 2012}}</ref> Although airbags are now required in every automobile sold in the United States, Hetrick's 1951 patent filing serves as an example of a "valuable" invention with little economic value to its inventor. Its first commercial use was not implemented until after the patent expired in 1971, at which point the airbag was installed in a few experimental [[Ford Motor Company|Ford]] cars.<ref>{{cite book|url= https://books.google.com/books?id=KgCXLF5u9dMC&pg=PA85|page=22.6 |title=Litigation services handbook: the role of the financial expert |editor-first=Roman L. |editor-last=Weil |editor-link1=Roman L. Weil|editor-first2=Peter B. |editor-last2=Frank |editor-first3=Kevin D. |editor-last3=Kreb |publisher=John Wiley |year=2009 |isbn=9780470286609 |access-date=16 March 2014}}</ref>

In 1964, a Japanese automobile engineer, [[:ja:小堀保三郎|Yasuzaburou Kobori]] (小堀保三郎), started developing an airbag "safety net" system. His design harnessed an explosive to inflate an airbag, for which he was later awarded patents in 14 countries. He died in 1975, before seeing the widespread adoption of airbag systems.<ref>{{cite web |url= http://www.jahfa.jp/jahfa6/pala/person5-1.htm |title=Achievements of Yasuzaburou Kobori |publisher=Japan Automotive Hall of Fame |language=ja |quote=Source of creative ideas, [he] started the development of the air bag as a starting point to develop a safety net of motor vehicles in 1964. |access-date=16 March 2014 |url-status=dead |archive-url= https://web.archive.org/web/20130802085217/http://www.jahfa.jp/jahfa6/pala/person5-1.htm |archive-date=2 August 2013 }}</ref><ref>{{cite web| url= http://zasshi.news.yahoo.co.jp/article?a=20150321-00818815-sspa-soci |title=「エアバッグ」生みの親は日本人だった （週刊SPA!）|work=Yahoo!ニュース |archive-url= https://web.archive.org/web/20150519022006/http://zasshi.news.yahoo.co.jp/article?a=20150321-00818815-sspa-soci |archive-date=19 May 2015 }}</ref><ref>{{cite web |url= http://nikkan-spa.jp/818815/airbag |title=エアバッグ - airbag.jpg – 日刊SPA! |work=日刊SPA! |url-status=dead |archive-url= https://web.archive.org/web/20150323145459/http://nikkan-spa.jp/818815/airbag |archive-date=23 March 2015 |date=21 March 2015 |access-date=13 October 2017 }}</ref>

In 1967, a breakthrough in developing airbag crash [[sensor]]s came when Allen K. Breed invented a ball-in-tube mechanism for crash detection. Under his system, an [[Electromechanics|electromechanical]] sensor with a steel ball attached to a tube by a [[magnet]] would inflate an airbag in under 30 milliseconds.<ref>{{cite news|url= https://www.nytimes.com/2000/01/14/business/allen-k-breed-72-a-developer-of-air-bag-technology-for-cars.html |title=Allen K. Breed, 72, a Developer of Air Bag Technology for Cars |first=Nick |last=Ravop |date=14 January 2000 |newspaper=The New York Times |access-date=28 March 2015 |url-status=live |archive-url= https://web.archive.org/web/20150402214752/http://www.nytimes.com/2000/01/14/business/allen-k-breed-72-a-developer-of-air-bag-technology-for-cars.html |archive-date=2 April 2015 }}</ref> A small explosion of [[sodium azide]] was used instead of compressed air during inflation for the first time.<ref name="Big Ideas"/> Breed Corporation then marketed this innovation to [[Chrysler]]. A similar "Auto-Ceptor" crash-restraint, developed by the [[Eaton Corporation|Eaton, Yale & Towne]] company for Ford, was soon also offered as an automatic safety system in the United States,<ref>{{cite magazine|url= https://books.google.com/books?id=qCUDAAAAMBAJ&dq=Pillow+protects+you+in+auto+crashes&pg=PA94 |title=Pillow protects you in auto crashes |page=94 |magazine=Popular Science |date=May 1968 |volume=192 |issue=5 |access-date=7 March 2024 |via=Google Books}}</ref><ref>{{cite web|url= http://web.mit.edu/invent/iow/breed.html |title=Inventor of the Week: Archive |website=web.mit.edu |access-date=27 February 2010 |url-status=dead |archive-url= https://web.archive.org/web/20090318103350/http://web.mit.edu/invent/iow/breed.html |archive-date=18 March 2009 }}</ref> while the Italian Eaton-Livia company offered a variant with localized{{explain|date=June 2014}} air cushions.<ref name=thetimes>{{cite news|title=Safety Design |first=John |last=Fenton |newspaper=The Times |date=24 January 1969}}</ref>

In the early 1970s, [[General Motors]] began offering cars equipped with airbags, initially in government [[fleet vehicle|fleet-purchased]] 1973 Chevrolet Impala sedans. These cars came with a 1974-style Oldsmobile instrument panel and a unique steering wheel that contained the driver-side airbag. Two of these cars were crash tested after 20 years and the airbags deployed perfectly.<ref>{{cite web |last=Phillips |first=David |title=Impalas' 1973 experimental airbags held up |url= https://www.autonews.com/article/20111031/CHEVY100/310319928/impalas-1973-experimental-airbags-held-up |publisher=Automotive News |date=31 October 2011 |access-date=1 August 2020}}</ref> An early example of the airbag cars survives as of 2009.<ref>{{cite magazine |last=Lorio |first=Joe |title=Whats this 73 Chevrolet Impala doing at a classic car auction? |url= https://www.automobilemag.com/news/whats-this-73-chevrolet-impala-doing-at-a-classic-car-auction-2-135242/ |magazine=Automobile Magazine |date=15 June 2009 |access-date=1 August 2020}}</ref> GM's [[Oldsmobile Toronado]] was the first domestic U.S. vehicle to include a passenger airbag in 1973.<ref>{{cite web|last1=Phillips |first1=David |title=Impalas' 1973 experimental airbags held up: Fleet customers tested 1,000 vehicles with cutting-edge technology |url= http://www.autonews.com/article/20111031/CHEVY100/310319928/impalas-1973-experimental-airbags-held-up |access-date=16 November 2017 |work=Automotive News |date=31 October 2011}}</ref> General Motors marketed its first airbag modules under the "Air Cushion Restraint System" name, or ACRS. The automaker discontinued the option for its 1977 [[model year]], citing a lack of consumer interest. Ford and GM then spent years [[lobbying]] against air-bag requirements, claiming that the devices were unfeasible and inappropriate. Chrysler made driver-side airbags standard on 1988 and 1989 models, but airbags did not become widespread in American cars until the early 1990s.<ref>{{cite news|first=Paul |last=Tullis |url= https://www.nytimes.com/packages/html/magazine/2013/innovations-issue/#/?part=airbag |title=Air Bag – Who Made That? The Magazine's 2013 Innovations Issue |newspaper=The New York Times |date=7 June 2013|url-status=live |archive-url= https://web.archive.org/web/20140215212225/http://www.nytimes.com/packages/html/magazine/2013/innovations-issue/ |archive-date=15 February 2014}}</ref>

=== As a substitute for seat belts ===
Airbags for passenger cars were introduced in the United States in the 1970s. When seat-belt usage rates in the country were quite low compared to modern-day, Ford built experimental cars with airbags in 1971. [[Allstate]] operated a fleet of 200 [[Mercury Monterey]]s and showed the reliability of airbags as well as their operation in crash testing, which also was promoted by the insurance company in popular magazine advertisements.<ref>{{cite magazine |title=Allstate fleet cars show the reliability of air bags (advertisement) |magazine=Life |date=9 June 1972 |volume=72 |issue=22 |pages=8–9 |url= https://books.google.com/books?id=9lYEAAAAMBAJ&q=Allstate+fleet+cars+show+the+reliability+of+air+bags&pg=PA6 |access-date=13 August 2021}}</ref> General Motors followed in 1973 using full-sized Chevrolet vehicles. The early fleet of experimental GM vehicles equipped with airbags experienced seven fatalities, one of which was later suspected to have been caused by the airbag.<ref>{{cite web |url= http://www.airbagcrash.com/contactusetc.html |title=GM's Acrs |website=airbagcrash.com |year=2001 |access-date=16 March 2014 |url-status=dead |archive-url= https://web.archive.org/web/20140223133516/http://www.airbagcrash.com/contactusetc.html |archive-date=23 February 2014 }}</ref>

In 1974, GM made its ACRS system (which consisted of a padded lower dashboard and a passenger-side air bag) available as a regular production option (RPO code AR3) in full-sized Cadillac,<ref>{{cite web|url= http://www.oldcarbrochures.com/static/NA/Cadillac/1975_Cadillac/1975_Cadillac_Brochure/1975%20Cadillac-25.html |title=1975 Cadillac Brochure |page=25 |website=oldcarbrochures.com |access-date=16 March 2014 |url-status=live |archive-url= https://web.archive.org/web/20140316214731/http://www.oldcarbrochures.com/static/NA/Cadillac/1975_Cadillac/1975_Cadillac_Brochure/1975%20Cadillac-25.html |archive-date=16 March 2014 }}</ref> Buick and Oldsmobile models. The GM cars from the 1970s equipped with ACRS had a driver-side airbag, and a driver-side knee restraint.<ref name="oldcarbrochures1974">{{cite web|url= http://www.oldcarbrochures.com/static/NA/Oldsmobile/1974_Oldsmobile/1974_Oldsmobile_Air_Cushion_Folder/1974%20Oldsmobile%20Air%20Cushion%20Folder-06-07.html |title=1974 Oldsmobile Air Cushion Folder |pages=6–7 |website=oldcarbrochures.com |access-date=16 March 2014 |url-status=dead |archive-url= https://web.archive.org/web/20141213023724/http://www.oldcarbrochures.com/static/NA/Oldsmobile/1974_Oldsmobile/1974_Oldsmobile_Air_Cushion_Folder/1974%20Oldsmobile%20Air%20Cushion%20Folder-06-07.html |archive-date=13 December 2014 }}</ref> The passenger-side airbag protected both front passengers,<ref name="oldcarbrochures1974"/> and unlike most modern systems, integrated a knee and torso cushion while also having a dual-stage deployment dictated by force of the impact. The cars equipped with ACRS had lap belts for all seating positions, but lacked shoulder belts. Shoulder belts were already mandatory in the United States on closed cars without airbags for the driver and outer front passenger, but GM chose to market its airbags as a substitute for shoulder belts. Prices for this option on Cadillac models were US$225 in 1974, $300 in 1975, and $340 in 1976 (US${{formatnum:{{Inflation|US|340|1976}}}} in {{Inflation-year|US}} dollars {{inflation-fn|US}}).

The early development of airbags coincided with international interest in automobile safety legislation. Some safety experts advocated a [[Risk assessment|performance-based]] occupant-protection standard rather than one mandating a particular technical solution (which could rapidly become outdated and prove to not be a [[Cost-effectiveness analysis|cost-effective]] approach). Less emphasis was placed on other designs as countries successfully mandated seat belt restrictions, however.<ref name=thetimes/>

=== As a supplemental restraint system ===
==== Frontal airbag ====
{{multiple image
| footer = Three photos of a crash test dummy whose head lands right into the airbag 
| image1 = Airbag1.jpg
| width1 = 150
| image2 = Airbag2.jpg
| width2 = 141 
| image3 = Airbag3.jpg
| width3 = 150
}}

The auto industry and research and regulatory communities have moved away from their initial view of the airbag as a seat-belt replacement, and the bags are now nominally designated as '''supplemental restraint systems''' ('''SRS''') or supplemental inflatable restraints.

In 1981, [[Mercedes-Benz]] introduced the airbag in [[West Germany]] as an option on its flagship saloon model, [[Mercedes-Benz W126|S-Class (W126)]]. In the Mercedes system, the sensors automatically tensioned the seat belts to reduce occupants' motion on impact and then deployed the airbag on impact. This integrated the seat belts and the airbag into a restraint system, rather than the airbag being considered an alternative to the seat belt.

In 1987, the [[Porsche 944]] Turbo became the first car to have driver and passenger airbags as standard equipment.<ref>{{cite news |url= https://www.excellence-mag.com/issues/179/articles/porsche-airbag-systems |title=Porsche Airbag Systems |first1=Tony |last1=Callas |first2=Tom |last2=Prine |work=Excellence Magazine |location=US |date=30 November 2009 |access-date=14 November 2022}}</ref> The Porsche 944 and 944S had this as an available option. The same year also had the first airbag in a Japanese car, the [[Honda Legend]].<ref>{{cite web |url= http://www.jsae.or.jp/autotech/data_e/7-3e.html |title=240 Landmarks of Japanese Automotive Technology – Subaru Legend airbag system |publisher=Society of Automotive Engineers of Japan |access-date=16 March 2014 |url-status=dead |archive-url= https://web.archive.org/web/20141123222600/http://www.jsae.or.jp/autotech/data_e/7-3e.html |archive-date=23 November 2014}}</ref>

In 1988, [[Chrysler]] became the first United States automaker to fit a driver-side airbag as standard equipment, which was offered in six different models.<ref name="Godshall">{{cite journal|url= https://books.google.com/books?id=duNp3hLLlkUC&pg=PA71|first=Jeffery|last=Godshall |title=Form, Function, and Fantasy – seventy years of Chrysler design |journal=Automobile Quarterly |volume=32 |issue=4 |pages=70–71 |access-date=27 April 2019 |isbn=9781596139275}}</ref><ref>{{cite magazine|url= http://www.automotive-fleet.com/article/story/1988/07/chrysler-introduces-driver-side-air-bags.aspx |title=Chrysler Introduces Driver-Side Air Bags |date=July 1988 |magazine=Automotive Fleet |access-date=27 April 2019 |url-status=live |archive-url= https://web.archive.org/web/20140316195140/http://www.automotive-fleet.com/article/story/1988/07/chrysler-introduces-driver-side-air-bags.aspx |archive-date=16 March 2014 }}</ref> The following year, Chrysler became the first US auto manufacturer to offer driver-side airbags in all its new passenger models.<ref>{{cite web |title=Automobile Safety |url= https://americanhistory.si.edu/america-on-the-move/essays/automobile-safety |work=National Museum of American History |date=24 July 2017 }}</ref><ref>{{cite book|url= https://books.google.com/books?id=K0Le2urkC0cC&pg=PA220|page=220 |title=Business ethics|first=William H. |last=Shaw |publisher=Wadsworth/Cengage |year=2011 |isbn=9780495808763 |access-date=16 March 2014}}</ref> Chrysler also began featuring the airbags in advertisements showing how the devices had saved lives that helped the public know the value of them and safety became a selling advantage in the late 1980s.<ref>{{cite magazine |title=1990 Government Mandates Safety |magazine=Popular Mechanics |date=May 1996 |volume=173 |issue=5 |page=59 |url= https://books.google.com/books?id=MWUEAAAAMBAJ&pg=PA59 |access-date=5 November 2019}}</ref> All versions of the [[Chrysler minivans (AS)|Chrysler minivans]] came with airbags starting for the 1991 model year.<ref name="Godshall"/> In 1993, The Lincoln Motor Company boasted that all vehicles in their model line were equipped with dual airbags, one for the driver's side and another for the passenger's side.<ref>{{cite AV media |url= https://www.youtube.com/watch?v=wMJSXyTnOhI |title=1993 Lincoln safety ad |via=YouTube}}</ref> The [[Jeep Grand Cherokee (ZJ)|1993 Jeep Grand Cherokee]] became the first SUV to offer a driver-side airbag when it was launched in 1992.<ref>{{cite magazine|url= https://books.google.com/books?id=pOMDAAAAMBAJ&pg=PA25|pages=25–27 |date=July 1993 |magazine=Popular Mechanics |title=Jeep Grand Cherokee – another home run for the home team |first=Michael |last=Lamm |volume=170 |issue=7 |access-date=16 March 2014}}</ref> Driver and passenger airbags became standard equipment in all [[Dodge Intrepid]], [[Eagle Vision]], and [[Chrysler Concorde]] sedans ahead of any safety regulations.<ref>{{cite book |url= https://books.google.com/books?id=mAZeW0y7h5sC&pg=PA147|page=147 |title=Air Bag Safety: Hearing Before the Committee on Commerce, Science, & Transportation, U.S. Senate |year=1996 |editor-first=Larry |editor-last=Pressler |publisher=Dianne Publishing |access-date=16 March 2014|isbn=9780788170676 }}</ref><ref>Legislation passed in 1991 required driver and front passenger airbags for passenger vehicles offered for sale in the US after September 1997 and for other vehicles after September 1998.{{cite book |title=Air Bag Safety: Hearing Before the Committee on Commerce, Science and Transportations US Senate 104 Congress 2nd session |url= https://books.google.com/books?id=R-bXBSwvBO8C&pg=PA3 |date=2 March 1996 |isbn=9780788170676 |last1=Pressler|first1=Larry| publisher=DIANE }}</ref> Early 1993 saw the 4-millionth airbag-equipped Chrysler vehicle roll off the assembly line.<ref>{{cite press release|url= http://www.thefreelibrary.com/CHRYSLER+AIR+BAG+PRODUCTION+HITS+4+MILLION+UNITS-a013141245 |title=Chrysler air bag production hits 4 million units |date=19 April 1993 |agency=PRNewswire |website=thefreelibrary.com |access-date=16 March 2014}}</ref> In October 1993, the [[Dodge Ram]] became the first [[pickup truck]] with a standard driver-side airbag.<ref>{{cite magazine|url= https://books.google.com/books?id=5-MDAAAAMBAJ&pg=PA24|page=24 |title=Design and Engineering Awards |magazine=Popular Mechanics |date=January 1994 |volume=171 |issue=1 |access-date=16 March 2014}}</ref>

The first known collision between two airbag-equipped automobiles took place on 12 March 1990 in [[Virginia]], USA. A 1989 [[Chrysler LeBaron]] crossed the [[Road surface marking|center line]] and hit another 1989 Chrysler LeBaron in a [[head-on collision]], causing both driver airbags to deploy. The drivers suffered only minor injuries despite extensive damage to the vehicles.<ref>{{cite news |url = https://www.proquest.com/docview/307238903 |title=Va. Crash Shines Spotlight on Air Bags; Safety Experts Say They Feel Vindicated in 20-Year Battle |date= 31 March 1990 |last1=Cohn |first1=D'Vera |last2=Henderson |first2=Nell |page=A.01 |newspaper=The Washington Post |archive-url= https://web.archive.org/web/20171013172923/https://pqasb.pqarchiver.com/washingtonpost/doc/307238903.html?FMT=ABS&FMTS=ABS:FT&date=Mar+31%2C+1990&author=Cohn%2C+D%27Vera%3B+Henderson%2C+Nell&pub=The+Washington+Post+%28pre-1997+Fulltext%29&edition=&startpage=a.01&desc=Va.+Crash+Shines+Spotlight+on+Air+Bags%3BSafety+Experts+Say+They+Feel+Vindicated+in+20-Year+Battle |archive-date=13 October 2017 |id={{ProQuest|307238903}} |url-status=live |df=dmy-all }}</ref><ref>{{cite news|url= https://www.orlandosentinel.com/1990/04/01/air-bags-save-2-lives-in-historic-collision/ |title=Air Bags Save 2 Lives in Historic Collision |date=1 April 1990 |newspaper=Orlando Sentinel |url-status=live |archive-url= https://web.archive.org/web/20160818150250/http://articles.orlandosentinel.com/1990-04-01/business/9003312872_1_woody-crash-bags |archive-date=18 August 2016 }}</ref><ref>{{citation|url= http://www.people.com/people/archive/article/0,,20117450,00.html |title=Dueling Air Bags Allow Two Virginia Drivers to Walk Away from a Horrifying Head-on Collision |date=23 April 1990 |volume=33 |issue=16 |magazine=[[People (magazine)|People]] |url-status=live |archive-url= https://web.archive.org/web/20160914213704/http://www.people.com/people/archive/article/0%2C%2C20117450%2C00.html |archive-date=14 September 2016 }}</ref>

The United States [[Intermodal Surface Transportation Efficiency Act]] of 1991 required passenger cars and light trucks built after 1 September 1998 to have airbags for the driver and the front passenger.<ref name="AirBagTechnology">{{cite web|url= http://www.nhtsa.gov.edgesuite-staging.net/DOT/NHTSA/NRD/Multimedia/PDFs/Crashworthiness/Air%20Bags/rev_report.pdf |page=1 |date=21 June 2001 |title=Air Bag Technology in Light Passenger Vehicles |author=((Office of Research and Development)) |publisher=U.S. NHTSA |access-date=16 March 2014 |url-status=live |archive-url= https://web.archive.org/web/20141215001813/http://www.nhtsa.gov.edgesuite-staging.net/DOT/NHTSA/NRD/Multimedia/PDFs/Crashworthiness/Air%20Bags/rev_report.pdf |archive-date=15 December 2014 }}</ref><ref>{{cite web|url= http://www.history.com/this-day-in-history/federal-legislation-makes-airbags-mandatory |title=Sep 1, 1998: Federal legislation makes airbags mandatory |website=history.com |date=13 November 2009 |access-date=16 March 2014 |url-status=live |archive-url= https://web.archive.org/web/20140316195048/http://www.history.com/this-day-in-history/federal-legislation-makes-airbags-mandatory |archive-date=16 March 2014 }}</ref> In the United States, NHTSA estimated that airbags had saved over 4,600 lives by 1 September 1999; however, the crash deployment experience of the early 1990s installations indicated that some fatalities and serious injuries were in fact caused by airbags.<ref name="AirBagTechnology"/> In 1998, NHTSA initiated new rules for advanced airbags that gave automakers more flexibility in devising effective technological solutions. The revised rules also required improved protection for occupants of different sizes regardless of whether they use seat belts, while minimizing the risk to infants, children, and other occupants caused by airbags.<ref name="AirBagTechnology"/>

In [[Europe]], airbags were almost unheard of until the early 1990s. By 1991, four manufacturers – [[BMW]], [[Honda]], Mercedes-Benz, and [[Volvo]] – offered the airbag on some of their higher-end models, but shortly afterward, airbags became a common feature on more mainstream cars, with [[Ford Motor Company|Ford]] and [[Vauxhall Motors|Vauxhall]]/[[Opel]] among the manufacturers to introduce the airbag to its model ranges in 1992. [[Citroën]], [[Fiat]], [[Nissan]], [[Hyundai Motor Group|Hyundai]], [[Peugeot]], [[Renault]], and [[Volkswagen]] followed shortly afterwards.

By 1999, finding a new mass-market car without an airbag at least as optional equipment was difficult, and some late 1990s products, such as the [[Volkswagen Golf Mk4]], also featured side airbags. The [[Peugeot 306]] is one example of the European automotive mass-market evolution: starting in early 1993, most of these models did not even offer a driver's airbag as an option, but by 1999, even side airbags were available on several variants. [[Audi]] was late to offer airbag systems on a broader scale, since even in the 1994 model year, its popular models did not offer airbags. Instead, the German automaker until then relied solely on its proprietary cable-based [[procon-ten]] restraint system.

[[Adaptive airbag|Variable force-deployment]] front airbags were developed to help minimize injury from the airbag itself.

The emergence of the airbag has contributed to a sharp decline in the number of deaths and serious injuries on the roads of Europe since 1990, and by 2010, the number of cars on European roads lacking an airbag represented a very small percentage of cars, mostly the remaining cars dating from the mid-1990s or earlier.

Many new cars in Latin America, including the [[Kia Rio]], [[Kia Picanto]], [[Hyundai Grand i10]], [[Mazda 2]], [[Chevrolet Spark]] and the [[Chevrolet Onix]], are often sold without airbags, as neither airbags nor [[Collision avoidance system|automatic braking]] systems in new cars are compulsory in many Latin American countries. Some require the installation of a minimum of only two airbags in new cars which many in this market have.<ref>{{cite news |url=https://www.elmundo.es/motor/2017/10/06/59d770ae22601d8e6e8b45b8.html |title=Latin NCAP: los vehículos de Latinoamérica, dos décadas por detrás en seguridad |trans-title=Latin NCAP: Latin American vehicles, two decades behind in safety |first=Denís |last=Iglesias |work=El Mundo |location=Spain |language=Spanish |date=10 October 2017 |access-date=24 July 2023}}</ref><ref>{{cite news |url= https://motor.elpais.com/conducir/por-que-un-coche-protege-mejor-en-europa-que-en-latinoamerica/ |title=¿Por qué un coche protege mejor en Europa que en Latinoamérica? |trans-title=Why does a car protect better in Europe than in Latin America? |first=Mario |last=Herráez |work=El Motor |location=Spain |language=Spanish |date=13 September 2021 |access-date=24 July 2023}}</ref><ref>{{cite news |url=https://www.elcolombiano.com/negocios/la-seguridad-de-los-carros-que-se-venden-en-america-latina-2023-OG21056585 |title=¿Por qué los carros que se venden en América Latina no son tan seguros como en Europa? |trans-title=Why are the cars sold in Latin America not as safe as in Europe? |first=Alejandra Zapata |last=Quinchía |work=El Colombiano |location=Colombia |language=Spanish |date=10 April 2023 |access-date=24 July 2023}}</ref>

===== Shape of airbags =====
The [[Citroën C4]] provided the first "shaped" driver airbag, made possible by this car's unusual fixed-hub steering wheel.<ref>{{cite news |url= http://www.theaustralian.news.com.au/story/0,20867,16128857-13232,00.html |archive-url= https://web.archive.org/web/20060512203054/http://theaustralian.news.com.au/story/0%2C20867%2C16128857-13232%2C00.html |url-status=dead |archive-date=12 May 2006 |title=Citroen C4 |last=Wilson |first=Robert |date=3 August 2005 |newspaper=The Australian |access-date=3 November 2009 }}</ref>

In 2019, Honda announced it would introduce a new front passenger airbag technology. Developed by [[Autoliv]] and Honda R&D in [[Ohio, United States]], this new airbag design features three inflatable chambers connected across the front by a "noninflatable sail panel." The two outer chambers are larger than the middle chamber. When the airbag deploys, the sail panel cushions the occupant's head from the impact of hitting the airbag, and the three chambers hold the occupant's head in place, like a catcher's mitt. The goal of the tri-chamber airbag is to help "arrest high-speed movement" of the head, thereby reducing the likelihood of concussion injuries in a collision. The first vehicle to come with the tri-chamber airbag installed from the factory was in 2020 (for the 2021 model year) for the [[Acura TLX]]. Honda hopes that the new technology will soon make its way to all vehicles.<ref>{{cite news |url= https://www.caranddriver.com/news/a28791083/honda-multi-compartment-airbag-cars/ |title=Honda's New Airbag Will Give Front Passengers Better Protection |first=Andrew |last=Wendler |work=Car and Driver |location=US |date=23 August 2019 |access-date=29 September 2022}}</ref>

===== Rear airbag =====
Mercedes began offering rear passengers protection in frontal collisions in September 2020 (for the 2021 model year) for the [[Mercedes-Benz S-Class (W223)]].<ref>{{cite news |url= https://www.cnet.com/roadshow/news/2021-mercedes-benz-s-class-safety-tech-rear-seat-airbags/ |title=2021 Mercedes-Benz S-Class safety tech: Rear-seat airbags and 48-volt architecture |first=Steven |last=Ewing |date=2 September 2020 |access-date=11 February 2023}}</ref> The W223 S-Class is the first car equipped with rear seat airbags that use gas to inflate supporting structures that unfold and extend a bag that fills with ambient air, instead of conventional fully gas-inflated airbags that are widely used in automotive airbag systems.<ref>{{cite news |url= https://www.caranddriver.com/news/a27535532/mercedes-benz-rear-seat-airbag-concept/ |title=An Airbag for the Back Seat? Mercedes-Benz Is Developing a Clever One |first=Alexander |last=Stoklosa |date=2019-05-22 |access-date=2023-02-11}}</ref><ref>{{cite news |url= https://www.autoblog.com/2020/07/29/2021-mercedes-benz-s-class-tech-preview/ |title=2021 Mercedes-Benz S-Class gets rear-axle steering and trick new airbag tech |first=Zac |last=Palmer |work=AutoBlog |date=29 July 2020 |access-date=11 February 2023}}</ref>

==== Side airbag ====
[[File:Seitenairbag Porsche.jpg|thumb|Side airbag on a [[Porsche 996]] inflated permanently for display purposes]]
[[File:Curtainairbags.JPG|thumb|Deployed curtain airbag and side torso airbag in a [[Citroën C4]] ]]

Essentially, two types of side airbags are commonly used today{{when|reason=What does "today" mean when read in 10 or 20 years time?|date=September 2022}} - the side-torso airbag and the side-curtain airbag. More recently,{{when|reason=What does "recently" mean when read in 10 or 20 years time?|date=September 2022}} center airbags are becoming more common in the European market.

Most vehicles equipped with side-curtain airbags also include side-torso airbags. However, some, such as the [[Chevrolet Cobalt]],<ref>{{cite web |url= http://www.iihs.org/ratings/ratingsbyseries.aspx?id=527 |title=IIHS-HLDI: Chevrolet Cobalt 4-door |website=iihs.org |access-date=16 March 2014 |url-status=dead |archive-url= https://web.archive.org/web/20130523132834/http://www.iihs.org/ratings/ratingsbyseries.aspx?id=527 |archive-date=23 May 2013 }}</ref> 2007–09 model [[Chevrolet Silverado|Chevrolet Silverado/GMC Sierra]], and 2009–12 [[Dodge Ram]]<ref>{{cite web|url= http://www.iihs.org/ratings/rating.aspx?id=1087 |title=IIHS-HLDI: Dodge Ram 1500 |website=iihs.org |date=16 March 2014 |url-status=live |archive-url= https://web.archive.org/web/20100410024807/http://www.iihs.org/ratings/rating.aspx?id=1087 |archive-date=10 April 2010 }}</ref> do not feature the side-torso airbag.

From around 2000, side-impact airbags became commonplace on even low- to mid-range vehicles, such as the smaller-engined versions of the [[Ford Fiesta]] and [[Peugeot 206]], and curtain airbags were also becoming regular features on mass-market cars. The [[Toyota Avensis]], launched in 2003, was the first mass-market car to be sold in Europe with nine airbags.

===== Side torso airbag =====
Side-impact airbags or side-torso airbags <!-- (side thorax/abdomen airbags) --> are a category of airbags usually located in the seat<ref>{{cite web |language=en |url= http://www.protext.cz/english/zprava.php?id%3D5890 |title=Johnson Controls develops and manufactures the instrument panel, seating system, door panels and acoustic parking system for the new Mercedes-Benz A-Class |archive-url= https://web.archive.org/web/20170302112307/http://www.protext.cz/english/zprava.php?id=5890 |archive-date=2 March 2017 |access-date=11 May 2018 |url-status=dead}}</ref> or door panel,<ref>{{cite web |url= http://www.motortrend.com/cars/mercedes-benz/e-class/1996/1996-mercedes-benz-eclass/ |title=1996 Mercedes-Benz E-Class – Roadtest – European Car |first=Rik |last=Paul |work=Motor Trend |date=1 January 1996 |archive-url= https://web.archive.org/web/20180304003839/http://www.motortrend.com/cars/mercedes-benz/e-class/1996/1996-mercedes-benz-eclass/ |archive-date=4 March 2018 |access-date=11 May 2018 |url-status=live}}</ref> and inflate between the seat occupant and the door. These airbags are designed to reduce the risk of injury to the pelvic and lower abdomen regions.<ref>{{cite web |language=en |url= http://www.freepatentsonline.com/7063350.html |title=Dual chamber side airbag apparatus and method |website=freepatentsonline.com |date=20 June 2006 |access-date=11 May 2018 }}</ref> Most vehicles are now being equipped with different types of designs, to help reduce injury and ejection from the vehicle in rollover crashes. More recent side-airbag designs<ref>{{cite press release |url= http://news.honda.com/newsandviews/article.aspx?id%3D4110-en |title=2008 Honda Accord – Safety |publisher=American Honda |date=21 August 2007 |archive-url= https://web.archive.org/web/20170302030917/http://news.honda.com/newsandviews/article.aspx?id=4110-en |archive-date=2 March 2017 |access-date=11 May 2018 |url-status=dead}}</ref> include a two-chamber system;<ref>{{cite press release |url= https://www.media.volvocars.com/us/en-us/media/pressreleases/3549 |title=All New Volvo S80: Style, Sophistication, Safety and Scandinavian |publisher=Volvo Cars US |date=28 February 2006 |archive-url= https://web.archive.org/web/20170302111856/https://www.media.volvocars.com/us/en-us/media/pressreleases/3549 |archive-date=2 March 2017 |access-date=1 March 2017 |url-status=live}}</ref> a firmer lower chamber for the pelvic region and softer upper chamber for the ribcage.<ref>{{cite web |language=en |url= http://xc60volvo.blogspot.de/2009/05/dual-chamber-side-airbags.html |title=Dual-chamber Side Airbags |date=23 October 2009 |archive-url= https://web.archive.org/web/20170202101456/http://xc60volvo.blogspot.de/2009/05/dual-chamber-side-airbags.html |archive-date=2 February 2017 |access-date=26 January 2017 |url-status=live}}</ref><ref>{{Cite journal |language=en |last1=Jakobsson |first1=Lotta |last2=Lindman |first2=Magdalena |last3=Svanberg |first3=Bo |last4=Carlsson |first4=Henrik |title=Real World Data Driven Evolution of Volvo Cars' Side Impact Protection Systems and their Effectiveness |journal=Annals of Advances in Automotive Medicine / Annual Scientific Conference |volume=54 |pages=127–136 |issn=1943-2461 |pmc=3242537 |pmid=21050597 |year=2010}}</ref>

Swedish company [[Autoliv|Autoliv AB]] was granted a patent on side-impact airbags, and they were first offered as an option in 1994<ref name="volvogroup.com">{{cite press release|url= http://www.volvogroup.com/group/global/en-gb/newsmedia/pressreleases/previous/1998/_layouts/CWP.Internet.VolvoCom/NewsItem.aspx?News.ItemId%3D22963%26News.Language%3Den-gb |title=Second-Generation Sips-Bag protects both chest and head |publisher=Volvo Group Global |date=17 July 1998 |archive-url= https://web.archive.org/web/20150630101018/http://www.volvogroup.com/group/global/en-gb/newsmedia/pressreleases/previous/1998/_layouts/CWP.Internet.VolvoCom/NewsItem.aspx?News.ItemId=22963&News.Language=en-gb |archive-date=30 June 2015 |access-date=15 January 2020 |url-status=dead}}</ref> on the 1995 [[Volvo 850]], and as standard equipment on all Volvo cars made after 1995.<ref name="volvogroup.com" />
In 1997, [[Saab Automobile|Saab]] introduced the first combined head and torso airbags with the launch of the [[Saab 9-5]].

Some cars, such as the 2010 [[Volkswagen Polo Mk5|Volkswagen Polo Mk.5]] have combined head- and torso-side airbags. These are fitted in the backrest of the front seats and protect the head and the torso.

===== Side tubular or curtain airbag =====
In 1997, the [[BMW 7 Series (E38)|BMW 7 Series]] and [[BMW 5 Series (E39)|5 Series]] were fitted with tubular-shaped head side airbags (inflatable tubular structure),<ref>{{cite web |url= http://www.zodiacautomotive.com/products/side-impact-rollover-protection/inflatable-tubular-structure-its/ |title=Zodiac Coating – Medical Silicone Gel Components |work=zodiacautomotive.com |archive-url= https://web.archive.org/web/20150109083508/http://www.zodiacautomotive.com/products/side-impact-rollover-protection/inflatable-tubular-structure-its/ |archive-date=9 January 2015 |access-date=3 September 2018 |url-status=dead}}</ref> the "Head Protection System (HPS)" as standard equipment.<ref>{{cite press release |url= http://www.theautochannel.com/news/press/date/19971030/press007605.html |title=BMW Head Protection System Sets New Standard in Side-Impact Protection in Latest IIHS Crash Test |author=((BMW of North America)) |website=theautochannel.com |date=30 October 1997 |archive-url= https://web.archive.org/web/20140316215210/http://www.theautochannel.com/news/press/date/19971030/press007605.html |archive-date=16 March 2014 |access-date=16 March 2014 |url-status=live}}</ref> This airbag was designed to offer head protection in side impact collisions and also maintained inflation for up to seven seconds for rollover protection. However, this tubular-shaped airbag design has been quickly replaced by an inflatable 'curtain' airbag.

In May 1998, Toyota began offering a side-curtain airbag deploying from the roof on the [[Toyota Progrès|Progrés]].<ref>{{cite web |url= http://www.theautochannel.com/news/2007/07/23/055878.html |title=Toyota to Make Side Airbags and Curtain Shield Airbags Standard on All New Passenger Vehicle Models in Japan |website=theautochannel.com |date=23 July 2007 |archive-url= https://web.archive.org/web/20140316215658/http://www.theautochannel.com/news/2007/07/23/055878.html |archive-date=16 March 2014 |access-date=16 March 2014 |url-status=live}}</ref> In 1998, the [[Volvo S80]] was given roof-mounted curtain airbags to protect both front and rear passengers.<ref>{{cite web |language=en |url= https://www.volvoclub.org.uk/press/s80/tech/s80tech3.shtml |title=Volvo S80 |website=volvoclub.org.uk |archive-url= https://web.archive.org/web/20160102080537/https://www.volvoclub.org.uk/press/s80/tech/s80tech3.shtml |archive-date=2 January 2016 |access-date=11 May 2018 |url-status=live}}</ref> Curtain airbags were then made standard equipment on all new Volvo cars from 2000 except for the first-generation [[Volvo C70|C70]], which received an enlarged side-torso airbag that also protects the head of front-seat occupants.<ref name="volvogroup.com"/> The second-generation C70 convertible received the world's first door-mounted, side-curtain airbags that deployed upwards.

Curtain airbags have been said to reduce brain injury or fatalities by up to 45% in a side impact with an SUV. These airbags come in various forms (e.g., tubular, curtain, door-mounted) depending on the needs of the application.<ref>{{cite web |url= http://www.safercar.gov/Vehicle+Shoppers/Air+Bags/Side-Impact+Air+Bags+(SABs) |title=Side-Impact Air Bags (SABs) |website=safercar.gov |archive-url= https://web.archive.org/web/20140316214326/http://www.safercar.gov/Vehicle%2BShoppers/Air%2BBags/Side-Impact%2BAir%2BBags%2B%28SABs%29 |archive-date=16 March 2014 |access-date=16 March 2014 |url-status=live}}</ref> Many recent [[Sport utility vehicle|SUVs]] and [[Multi-purpose vehicle|MPVs]] have a long inflatable curtain airbag that protects all rows of seats.

In many vehicles, the curtain airbags are programmed to deploy during some/all frontal impacts to manage passenger kinetics (e.g. head hitting B-pillar on the rebound), especially in offset crashes such as the IIHS's small overlap crash test.

====== Roll-sensing curtain airbag (RSCA) ======
Roll-sensing curtain airbags are designed to stay inflated for a longer duration of time, cover a larger proportion of the window, and be deployed in a roll-over crash. They offer protection to occupants' heads and help to prevent ejection. SUVs and pickups are more likely to be equipped with RSCAs due to their higher probability of rolling over and often a switch can disable the feature in case the driver wants to take the vehicle off-road.

===== Center airbag =====
{{Update|section|date=February 2019}}
[[File:V08232P024.jpg|thumb|Front-center airbag of a [[Chevrolet Traverse]] deployed in a static out-of-position test: The purpose of the test was to find out how this airbag affects a 3-year-old child who is out of his seat and in the direct reach of the airbag.]]
[[File:Gurtairbag.jpg|thumb|upright|[[Ford Motor Company|Ford]] seat belt airbag]]

In 2009, Toyota developed the first production rear-seat center airbag designed to reduce the severity of secondary injuries to rear passengers in a side collision. This system deploys from the rear center seat first appearing in on the [[Toyota Crown Majesta|Crown Majesta]].<ref>{{cite web|url= http://www.worldcarfans.com/109031117798/toyota-develops-worlds-first-rear-seat-center-airbag |title=Toyota Develops World's First Rear-seat Center Airbag |website=worldcarfans.com |date=11 March 2009 |access-date=16 March 2014 |url-status=live |archive-url= https://web.archive.org/web/20140316213508/http://www.worldcarfans.com/109031117798/toyota-develops-worlds-first-rear-seat-center-airbag |archive-date=16 March 2014 }}</ref> In late 2012, General Motors with supplier Takata introduced a front center airbag; it deploys from the driver's seat.<ref>{{cite web|first=Zach |last=Bowman |url= http://www.autoblog.com/2011/09/29/gm-debuts-new-front-center-airbag-w-video/ |title=GM debuts new front center airbag |website=autoblog.com |date=29 September 2011 |access-date=16 March 2014 |url-status=live |archive-url= https://web.archive.org/web/20140316224521/http://www.autoblog.com/2011/09/29/gm-debuts-new-front-center-airbag-w-video/ |archive-date=16 March 2014 }}</ref>

[[Hyundai Motor Group]] announced its development of a center-side airbag on September 18, 2019, installed inside the driver's seat.

Some [[Volkswagen]] vehicles in 2022 equipped with center airbags include the [[Volkswagen ID.3|ID.3]] and the [[Volkswagen Golf Mk8|Golf]].<ref>{{cite press release|title=New ID.3: 'Today, safety wouldn't be possible without simulation'|url= https://www.volkswagen-newsroom.com:443/en/stories/new-id3-today-safety-wouldnt-be-possible-without-simulation-5429 |work=Volkswagen Newsroom |access-date=30 May 2020}}</ref>

The [[Polestar 2]] also includes a center airbag.

With EuroNCAP updating its testing guidelines in 2020, European and Australian market vehicles increasingly use front-center airbags, rear torso airbags, and rear seat belt pre-tensioners.<ref>{{Cite web |last=Fourin |first=FOURIN |date=June 2024 |title=Center-Side, External Airbags to Be Introduced for Euro NCAP Requirements |url=https://aaa.fourin.com/reports/bf991250-f087-11e9-9087-3d9b752d93ee/center-side-external-airbags-to-be-introduced-for-euro-ncap-requirements |website=AAA weekly - Asian Automotive Analysis |language=en}}</ref>

==== Knee airbag ====
The second driver-side and separate knee airbag was used in the [[Kia Sportage]] SUV and has been standard equipment since then. The airbag is located beneath the steering wheel.<ref>{{cite web|url= http://cms.firehouse.com/web/online/University-of-Extrication/Kia-Motors-Knee-Airbag-System/19$708 |archive-url= https://archive.today/20070731071404/http://cms.firehouse.com/web/online/University-of-Extrication/Kia-Motors-Knee-Airbag-System/19$708 |url-status=dead |archive-date=31 July 2007 |title=Kia Motors' Knee Airbag System &#124; Firehouse.com |website=cms.firehouse.com |access-date=8 December 2009 }}</ref><ref>{{cite web|url= https://www.latimes.com/archives/la-xpm-1996-05-24-fi-9924-story.html |title=New Air Bag Will Aim For Knees, Legs |work=Los Angeles Times |url-status=live |archive-url= https://web.archive.org/web/20151208075015/http://articles.latimes.com/1996-05-24/business/fi-9924_1_chest-air-bags |archive-date=8 December 2015 |date=24 May 1996 }}</ref>

[[File:V08589P076.jpg|thumb|Deployed passenger knee airbag in a [[Toyota Tundra]] after a frontal collision test, the driver-side knee airbag was also deployed. Blue and yellow markings indicate the dummy's knees.]]

The [[Toyota Caldina]] introduced the first driver-side SRS knee airbag on the Japanese market in 2002.<ref>{{cite web|url= http://www.toyota-global.com/company/history_of_toyota/75years/data/automotive_business/products_technology/technology_development/electronics_parts/index.html |title=Technical Development: Electronics Parts|work=toyota-global.com |url-status=live |archive-url= https://web.archive.org/web/20150324075624/http://www.toyota-global.com/company/history_of_toyota/75years/data/automotive_business/products_technology/technology_development/electronics_parts/index.html |archive-date=24 March 2015 }}</ref> [[Toyota Avensis]] became the first vehicle sold in Europe equipped with a driver's knee airbag.<ref>{{cite web|url= http://www.toyota.eu/06_Safety/04_implementing_passive_safety/02_airbags.aspx |title=Airbags |work=Toyota Europe |archive-url= https://web.archive.org/web/20090624034121/http://www.toyota.eu/06_Safety/04_implementing_passive_safety/02_airbags.aspx |archive-date=24 June 2009}}</ref><ref>{{cite press release|url= http://www.toyoda-gosei.com/news/2003/030630.html |title=Euro NCAP praises the new Driver-Side SRS Knee Airbag manufactured by Toyoda Gosei |work=Toyoda Gosei |date=30 June 2003 |access-date=16 March 2014 |url-status=dead |archive-url= https://web.archive.org/web/20130619041547/http://www.toyoda-gosei.com/news/2003/030630.html |archive-date=19 June 2013 }}</ref> The [[EuroNCAP]] reported on the 2003 Avensis, "There has been much effort to protect the driver's knees and legs and a knee airbag worked well."<ref>{{cite web|url= http://www.euroncap.com/tests/toyota_avensis_2003/172.aspx |title=Toyota Avensis |publisher=Euro NCAP |access-date=16 March 2014 |url-status=live |archive-url= https://web.archive.org/web/20130624135027/http://euroncap.com/tests/toyota_avensis_2003/172.aspx |archive-date=24 June 2013 }}</ref> Since then certain models have also included front-passenger knee airbags, which deploy near or over the [[glove compartment]] in a crash. Knee airbags are designed to reduce leg injury. The knee airbag has become increasingly common since 2000.

==== Rear curtain airbag ====
In 2008, the new [[Toyota iQ]] microcar featured the first production rear-curtain shield airbag to protect the rear occupants' heads in the event of a rear-end impact.<ref>{{cite web |last=Abuelsamid |first=Sam |url= http://www.autobloggreen.com/2008/09/30/toyota-develops-rear-curtain-airbag-for-tiny-iq/ |title=Toyota develops rear curtain airbag for tiny iQ |website=autobloggreen.com |date=30 September 2008 |access-date=16 March 2014 |url-status=dead |archive-url= https://web.archive.org/web/20090414062617/http://www.autobloggreen.com/2008/09/30/toyota-develops-rear-curtain-airbag-for-tiny-iq |archive-date=14 April 2009 }}</ref>

==== Seat cushion airbag ====
Another feature of the Toyota iQ was a seat-cushion airbag in the passenger seat to prevent the pelvis from diving below the lap belt during a frontal impact or submarining.<ref>{{cite web|url= http://www.toyota-global.com/innovation/safety_technology/safety_technology/technology_file/passive/srs_airbag/seat_cushion.html |title=Mobility |access-date=1 March 2017 |url-status=live |archive-url= https://web.archive.org/web/20160225013819/http://www.toyota-global.com/innovation/safety_technology/safety_technology/technology_file/passive/srs_airbag/seat_cushion.html |archive-date=25 February 2016 }}</ref> Later Toyota models such as the Yaris added the feature to the driver's seat, as well.

==== Seat-belt airbag ====
The seat-belt airbag is designed to better distribute the forces experienced by a buckled person in a crash using an increased seat belt area. This is done to reduce possible injuries to the rib cage or chest of the belt wearer.
*2010: [[Ford Explorer]]<ref name=fbeltairbags>{{cite web |url= https://media.ford.com/content/fordmedia/fna/us/en/news/2013/08/13/ford-expands-availability-of-rear-inflatable-safety-belt-to-2014.html |title=Ford Expands Availability of Rear Inflatable Safety Belt to 2014 Fusion |work=ford.com |archive-url= https://web.archive.org/web/20151006051112/https://media.ford.com/content/fordmedia/fna/us/en/news/2013/08/13/ford-expands-availability-of-rear-inflatable-safety-belt-to-2014.html |archive-date=6 October 2015 |url-status=dead |access-date=17 September 2015}}</ref> and 2013 [[Ford Flex]]: optional rear seat belt airbags; standard on the 2013 [[Lincoln MKT]]
*2010: [[Lexus LFA]]<ref>{{cite press release |url= http://us.aving.net/news/view.php?articleId=177230 |title=Takata First to Commercialize Front Seat Safety "Airbelt" for Passenger Cars |website=us.aving.net/news |date=6 December 2010 |archive-url= https://web.archive.org/web/20140426234136/http://us.aving.net/news/view.php?articleId=177230 |archive-date=26 April 2014 |access-date=11 April 2013 |url-status=live}}</ref> had seat belt airbags for driver and passenger<ref>{{cite web |url= http://www.caranddriver.com/reviews/2012-lexus-lfa-review |title=2012 Lexus LFA |work=Car and Driver |archive-url= https://web.archive.org/web/20150914203008/http://www.caranddriver.com/reviews/2012-lexus-lfa-review |archive-date=14 September 2015 |url-status=live|date=20 October 2009 }}</ref>
*2013: [[Mercedes-Benz S-Class (W222)]] has rear seat ''belt bags''<ref>{{cite web |url= http://media.daimler.com/dcmedia/0-921-1549267-1-1549474-1-0-0-1549717-0-1-11702-0-0-1-0-0-0-0-0.html?TS=1419880077161 |title=Extended protection in the rear: The seat belt gets into top shape |work=daimler.com |date=19 November 2012 |archive-url= https://web.archive.org/web/20160102080537/http://media.daimler.com/dcmedia/0-921-1549267-1-1549474-1-0-0-1549717-0-1-11702-0-0-1-0-0-0-0-0.html?TS=1419880077161 |archive-date=2 January 2016 |url-status=dead |access-date=17 September 2015}}</ref>
*2014: [[Ford Mondeo (fourth generation)|Ford Mondeo Mk IV]]<ref>{{cite web |url= https://media.ford.com/content/fordmedia-mobile/fap/th/en/news/2013/08/13/ford-mondeo-introduces-inflatable-seatbelts--a-ford-first-for-au.html |title=Ford Mondeo Introduces Inflatable Seatbelts, a Ford First for Australian customers |work=ford.com |archive-url= https://web.archive.org/web/20160102080537/https://media.ford.com/content/fordmedia-mobile/fap/th/en/news/2013/08/13/ford-mondeo-introduces-inflatable-seatbelts--a-ford-first-for-au.html |archive-date=2 January 2016 |url-status=dead}}</ref> has optional rear seat belt airbags for the two outer seats<ref>{{cite web |url= http://www.consumerreports.org/cro/news/2011/03/the-ford-inflatable-seat-belt-how-it-affects-car-seats-and-children/index.htm |title=The Ford inflatable seat belt: How it affects car seats and children |website=consumerreports.org |archive-url= https://web.archive.org/web/20150916051302/http://www.consumerreports.org/cro/news/2011/03/the-ford-inflatable-seat-belt-how-it-affects-car-seats-and-children/index.htm |archive-date=16 September 2015 |url-status=live}}</ref>

[[Cessna Aircraft]]<ref>{{cite web|url= http://cessna.txtav.com/citation-service/featured-parts/amsafe-inflatable-seatbelts |title=AmSafe Inflatable Seatbelts |work=Cessna |url-status=live |archive-url= https://web.archive.org/web/20150914023903/http://cessna.txtav.com/citation-service/featured-parts/amsafe-inflatable-seatbelts |archive-date=14 September 2015}}</ref> also introduced seat belt airbags.<ref name = cessnaairbags/> They are as of 2003<ref name=cessnaairbags>{{cite web |url= http://www.flyingmag.com/blogs/fly-wire/are-airbags-worth-money |title=Are Airbags Worth the Money? |work=Flying Magazine |date=20 January 2011 |archive-url= https://web.archive.org/web/20160102080538/http://www.flyingmag.com/blogs/fly-wire/are-airbags-worth-money |archive-date=2 January 2016 |url-status=live}}</ref> standard on the 172, 182, and 206.

==== Pedestrian airbag====
Airbag(s) mounted to the exterior of vehicles, so-called "pedestrian airbags", are designed to reduce injuries in the event of a vehicle to a pedestrian collision.<ref>{{cite web |url= http://www-nrd.nhtsa.dot.gov/pdf/esv/esv23/23ESV-000447.PDF |title=Pedestrian Airbag Technology – a Production System |archive-url= https://web.archive.org/web/20161004224711/http://www-nrd.nhtsa.dot.gov/pdf/esv/esv23/23ESV-000447.PDF |archive-date=4 October 2016 |access-date=4 July 2016 |url-status=dead}}</ref> When a collision is detected the airbag will deploy and cover hard areas, such as a-pillars<ref name=LRDS>{{cite web |url= https://www.youtube.com/watch?v=ZqOJageFVY8 |title=Land Rover Discovery Sport – Pedestrian Airbag |last=LandRoverMENA |date=1 October 2014 |via=YouTube |archive-url= https://web.archive.org/web/20170602042022/https://www.youtube.com/watch?v=ZqOJageFVY8 |archive-date=2 June 2017 |url-status=live}}</ref> and bonnet edges, before they can be struck by the pedestrian.<ref>{{cite web |url= https://www.youtube.com/watch?v=gauwfbKZAPc |title=YouTube |website=youtube.com |archive-url= https://web.archive.org/web/20170602042022/https://www.youtube.com/watch?v=gauwfbKZAPc |archive-date=2 June 2017 |url-status=live}}</ref> 
When introduced in 2012 the [[Volvo V40 (P1)|Volvo V40]] included the world's first pedestrian airbag as standard.<ref>{{cite web |language=en |url= http://www.news.com.au/technology/science/volvo-offers-worlds-first-pedestrian-airbag/story-fn5fsgyc-1226579835911 |title=Volvo offers world's first pedestrian airbag |first=Joshua |last=Dowling |work= NewsComAu |date=17 February 2013 |archive-url= https://web.archive.org/web/20141202035414/http://www.news.com.au/technology/science/volvo-offers-worlds-first-pedestrian-airbag/story-fn5fsgyc-1226579835911 |archive-date=2 December 2014 |access-date=5 July 2016 |url-status=live}}</ref> As a result, the V40 ranked highest (88%) in the EuroNCAP's pedestrian tests.<ref>{{cite web |language=en |url= http://www.euroncap.com/results/volvo/v40/485.aspx |title=Volvo V40 |publisher=Euro NCAP |date=August 2013 |archive-url= https://web.archive.org/web/20131015141326/http://www.euroncap.com/results/volvo/v40/485.aspx |archive-date=15 October 2013 |access-date=16 March 2014 |url-status=live}}</ref>

====Manufacturers====
Suppliers of SRS airbags include [[Autoliv]], [[Daicel]], [[TRW Automotive|TRW]], and [[Joyson Safety Systems|JSS]] (which owns Breed, Key Safety Systems, and Takata). The majority of impact sensors of airbags are manufactured by the Lanka Harness Company.{{citation needed|date=September 2022}}

== Operation ==
{{more citations needed section|date=May 2016}}
[[File:2008-04-14 Airbag control unit.jpg|thumb|An ACU from a [[Geo Storm]] ]]
The airbags in the vehicle are controlled by a central airbag control unit<ref>{{cite web| url= http://www.audi.com/audi/com/en2/tools/glossary/safety/airbag_control_unit.html |title=Airbag control unit |work=Audi |archive-url= https://web.archive.org/web/20081205193106/http://www.audi.com/audi/com/en2/tools/glossary/safety/airbag_control_unit.html |archive-date=5 December 2008 }}</ref> (ACU), a specific type of [[Electronic control unit|ECU]]. The ACU monitors several related sensors within the vehicle, including [[accelerometers]], impact sensors, side (door) pressure sensors,<ref>{{cite journal|last=Garcia |first=P. |title=A Methodology for the Deployment of Sensor Networks |journal=IEEE Transactions on Knowledge and Data Engineering |volume=11 |issue=4 |date=December 2011}}</ref> [[wheel speed sensor]]s, [[gyroscope]]s, [[pressure sensor|brake pressure sensors]], and seat occupancy sensors. Oftentimes, ACUs log this—and other—sensor data in a circular buffer and record it to onboard non-volatile memory, to provide a snapshot of the crash event for investigators. As such, an ACU frequently functions as the vehicle's [[event data recorder]] (EDR); not all EDRs are ACUs, and not all ACUs include EDR features.{{r|TRB-report|p=15}} An ACU typically includes capacitors within its circuitry, so that the module remains powered and able to deploy the airbags if the vehicle's battery connection to the ACU is severed during a crash.{{r|TRB-report|p=102}}{{r|MCFRS|p=3}}

The bag itself and its inflation mechanism are concealed within the steering wheel boss (for the driver), or the dashboard (for the front passenger), behind plastic flaps or doors that are designed to tear open under the force of the bag inflating. Once the requisite threshold has been reached or exceeded, the airbag control unit will trigger the ignition of a [[gas generator]] propellant to rapidly inflate a fabric bag. As the vehicle occupant collides with and squeezes the bag, the gas escapes in a controlled manner through small vent holes. The airbag's volume and the size of the vents in the bag are tailored to each vehicle type, to spread out the deceleration of (and thus force experienced by) the occupant over time and over the occupant's body, compared to a seat belt alone.

The signals from the various sensors are fed into the airbag control unit, which determines from them the angle of impact, the severity, or the force of the crash, along with other variables. Depending on the result of these calculations, the ACU may also deploy various additional restraint devices, such as [[seat belt]] pre-tensioners, and/or airbags (including frontal bags for driver and front passenger, along with seat-mounted side bags, and "curtain" airbags which cover the side glass). Each restraint device is typically activated with one or more [[pyrotechnic]] devices, commonly called an initiator or [[electric match]]. The electric match, which consists of an electrical conductor wrapped in a combustible material, activates with a current pulse between {{val|1|and|3|u=amps}} in less than 2 milliseconds. When the conductor becomes hot enough, it ignites the combustible material, which initiates the gas generator. In a seat belt pre-tensioner, this hot gas is used to drive a piston that pulls the slack out of the seat belt. In an airbag, the initiator is used to ignite solid propellant inside the airbag inflator. The burning propellant generates inert gas which rapidly inflates the airbag in approximately {{val|20|to|30|u=ms}}. An airbag must inflate quickly to be fully inflated by the time the forward-traveling occupant reaches its outer surface. Typically, the decision to deploy an airbag in a frontal crash is made within {{val|15|to|30|u=ms}} after the onset of the crash, and both the driver and passenger airbags are fully inflated within approximately {{val|60|to|80|u=ms}}  after the first moment of vehicle contact. If an airbag deploys too late or too slowly, the risk of occupant injury from contact with the inflating airbag may increase. Since more distance typically exists between the passenger and the instrument panel, the passenger airbag is larger and requires more gas to fill it.

Older airbag systems contained a mixture of [[sodium azide]] ({{chem2|NaN3}}), {{chem2|KNO3}}, and {{chem2|SiO2}}. A typical driver-side airbag contains approximately {{convert|50–80|g|oz}} of {{chem2|NaN3}}, with the larger passenger-side airbag containing about {{convert|250|g|oz}}. Within about 40 milliseconds of impact, all these components react in three separate reactions that produce nitrogen gas. The reactions, in order, are as follows.

# {{chem2|2 NaN3 -> 2 Na + 3 N2(g)}}
# {{chem2|10 Na + 2 KNO3 -> K2O + 5 Na2O + N2(g)}}
# {{chem2|K2O + Na2O + 2 SiO2 -> K2SiO3 + Na2SiO3}}

The first two reactions create 4 molar equivalents of nitrogen gas, and the third converts the remaining reactants to relatively inert [[potassium silicate]] and [[sodium silicate]].

Modern airbags use [[guanidine nitrate]] to generate gas through the following reaction:<ref>{{Cite web |title=What chemicals make airbags inflate, and how have they changed over time? |url=https://cen.acs.org/safety/chemicals-make-airbags-inflate-changed/100/i41 |access-date=2025-07-11 |website=Chemical & Engineering News |date=21 January 2025 |language=en}}</ref>

:{{chem2 | [C(NH2)3]NO3 (s) -> 3 H2O (g) + 2 N2 (g) + C (s) }}

There are ongoing efforts to find alternative compounds so that airbags have less toxic reactants.<ref>{{Cite web|url= http://www.gwp.eu/fileadmin/seiten/DEMO-Berichte/DEMO_Bericht_20050322_airbag_services_Rev05.pdf |archiveurl= https://web.archive.org/web/20140202143520/http://www.gwp.eu/fileadmin/seiten/DEMO-Berichte/DEMO_Bericht_20050322_airbag_services_Rev05.pdf |url-status=dead|title=Tests on Airbags: Analyses of Gases, Dusts, Structures and Squibs |archivedate=2 February 2014}}</ref> The reaction of the Sr complex nitrate, ({{chem2|SrOC(N2H3)2*(NO3)2}}) of [[carbohydrazide]] (SrCDH) with various oxidizing agents results in the evolution of {{chem2|N2}} and {{chem2|CO2}} gases. The {{chem2|N2}} and {{chem2|CO2}} gases evolved made up 99% of all gases evolved. Nearly all{{specify|date=June 2025}} of the starting materials will not decompose until reaching temperatures of {{convert|500|C|F}} or higher, so this could be a viable option as an airbag gas generator.<ref>{{cite journal|doi=10.1002/1521-4087(200011)25:5<224::AID-PREP224>3.0.CO;2-O |title=The Strontium Complex Nitrates of Carbohydrazide as a Non-Azide Gas Generator for Safer Driving-the Thermal Behavior of the Sr Complex with Various Oxidizing Agents |journal=Propellants, Explosives, Pyrotechnics |volume=25 |issue=5 |pages=224–229 |year=2000 |last1=Akiyoshi |first1=Miyako |last2=Nakamura |first2=Hidetsugu |last3=Hara |first3=Yasutake|doi-access=free }}</ref>

Since airbags deploy only once and deflate quickly after the initial impact, they will not be beneficial during a subsequent collision.<ref>{{cite web |title=Air Bags |url= https://www.chop.edu/pages/air-bags |publisher=The Children's Hospital of Philadelphia |date=30 March 2014 |access-date=18 July 2022}}</ref>

In vehicles equipped with a rollover sensing system, accelerometers, and gyroscopes are used to sense the onset of a rollover event. If a rollover event is determined to be imminent, [[Side curtain airbag|side-curtain]] airbags are deployed to help protect the occupant from contact with the side of the vehicle interior, and also to help prevent occupant ejection as the vehicle rolls over.

=== Triggering conditions ===
[[File:Peugeot 206 1999 Hatchback 1.1 TU1JP(HFZ) 05.JPG|thumb|Some cars provide the option to turn off the passenger airbag]]
Airbags are designed to deploy in frontal and near-frontal collisions more severe than a threshold defined by the regulations governing vehicle construction in whatever particular market the vehicle is intended for: United States regulations require deployment in crashes at least equivalent in deceleration to a {{convert|23|km/h|mph|abbr=on}} barrier collision, or similarly, striking a parked car of similar size across the full front of each vehicle at about twice the speed.<ref>{{cite web|url= http://www.nhtsa.gov/people/injury/airbags/airbags03/page3.html |title=What You Need to Know About Air Bags, DOT HS 809 575 |website=nhtsa.gov |access-date=17 October 2010 |url-status=dead |archive-url= https://web.archive.org/web/20100528074720/http://www.nhtsa.gov/people/injury/airbags/airbags03/page3.html |archive-date=28 May 2010}}</ref> International regulations are performance-based, rather than technology-based, so airbag deployment threshold is a function of overall vehicle design.

Unlike [[crash test]]s into barriers, real-world crashes typically occur at angles other than directly into the front of the vehicle, and the crash forces usually are not evenly distributed across the front of the vehicle. Consequently, the relative speed between a striking and struck vehicle required to deploy the airbag in a real-world crash can be much higher than an equivalent barrier crash. Because airbag sensors measure deceleration, the vehicle speed is not a good indicator of whether an airbag should be deployed. Airbags can deploy due to the vehicle's undercarriage striking a low object protruding above the roadway due to the resulting deceleration.

The airbag sensor is a [[Microelectromechanical systems|MEMS]] [[accelerometer]], which is a small [[integrated circuit]] with integrated micromechanical elements. The microscopic mechanical element moves in response to rapid deceleration, and this motion causes a change in capacitance, which is detected by the electronics on the chip that then sends a signal to fire the airbag. The most common MEMS accelerometer in use is the ADXL-50 by [[Analog Devices]],{{as of when?|date=June 2025}} but there are other MEMS manufacturers as well.

Initial attempts using [[mercury switch]]es did not work well. Before MEMS, the primary system used to deploy airbags was called a "[[rolamite]]". A rolamite is a mechanical device, consisting of a roller suspended within a tensioned band. As a result of the particular geometry and material properties used, the roller is free to translate with little [[friction]] or [[hysteresis]]. This device was developed at [[Sandia National Laboratories]]. Rolamite and similar macro-mechanical devices were used in airbags until the mid-1990s after which they were universally replaced with MEMS.

Nearly all airbags are designed to automatically deploy in the event of a vehicle fire when temperatures reach {{convert|150|–|200|C|F}}.<ref>{{cite web|url= http://www.nhtsa.dot.gov/people/injury/airbags/airbags03/page3.html |title=What You Need to Know About Air Bags, DOT HS 809 575 |website=nhtsa.dot.gov |archive-url= https://web.archive.org/web/20091126011343/http://www.nhtsa.dot.gov/people/injury/airbags/airbags03/page3.html|archive-date=26 November 2009 |access-date=16 March 2014}}</ref> This safety feature, often termed auto-ignition, helps to ensure that such temperatures do not cause an explosion of the entire airbag module.

Today{{when|date=January 2023}}, airbag triggering [[algorithms]] are much more complex, being able to adapt the deployment speed to the crash conditions, and prevent unnecessary deployments. The algorithms are considered valuable [[intellectual property]]. Experimental algorithms may take into account such factors as the weight of the occupant, the seat location, and seat belt use, as well as even attempt to determine if a [[baby seat]] is present.

==== Inflation ====
{{one source | section|date=May 2016}}
When the frontal airbags are to deploy, a signal is sent to the gas generator|inflator unit within the airbag control unit. An igniter starts a rapid chemical reaction generating primarily nitrogen gas ({{chem2|N2}}) to fill the airbag making it deploy through the module cover. Some airbag technologies use compressed nitrogen or [[argon]] gas with a pyrotechnic operated valve ("hybrid gas generator"), while other technologies use various energetic propellants. Although propellants containing the highly toxic sodium azide ({{chem2|NaN3}}) were common in early inflator designs, little to no toxic sodium azide has been found on used airbags.

The azide-containing pyrotechnic gas generators contain a substantial amount of the propellant. The driver-side airbag would contain a canister containing about {{convert|50|g|oz}}  of sodium azide. The passenger side container holds about {{convert|200|g|oz}} of sodium azide.<ref>{{cite web|url= http://www.sdearthtimes.com/et0800/et0800s9.html |title=ET 08/00: Sodium azide in car airbags poses a growing environmental hazard |website=sdearthtimes.com |access-date=16 March 2014 |url-status=live |archive-url= https://web.archive.org/web/20140917155736/http://www.sdearthtimes.com/et0800/et0800s9.html |archive-date=17 September 2014 }}</ref>{{better source needed|date=May 2016}}

From the onset of the crash, the entire deployment and inflation process is about 0.04 seconds. Because vehicles change speed so quickly in a crash, airbags must inflate rapidly to reduce the risk of the occupant hitting the vehicle's interior.<ref>{{Cite web |title=Airbags |url=https://www.iihs.org/topics/airbags |access-date=2025-04-24 |website=IIHS-HLDI crash testing and highway safety |language=en}}</ref><ref>{{Cite web |title=How do air bags work? |url=https://www.scientificamerican.com/article/how-do-air-bags-work/ |access-date=2025-04-24 |website=Scientific American |language=en}}</ref>

==== Variable-force deployment ====
Advanced airbag technologies are being developed to tailor airbag deployment to the severity of the crash, the size, and posture of the vehicle occupant, belt usage, and how close that person is to the actual airbag. Many of these systems use multi-stage inflators that deploy less forcefully in stages in moderate crashes than in very severe crashes. Occupant sensing devices let the airbag control unit know if someone is occupying a seat adjacent to an airbag, the mass/weight of the person, whether a seat belt or child restraint is being used, and whether the person is forward in the seat and close to the airbag. Based on this information and crash severity information, the airbag is deployed at either a high force level, a less forceful level, or not at all.

Adaptive airbag systems may utilize multi-stage airbags to adjust the pressure within the airbag. The greater the pressure within the airbag, the more force the airbag will exert on the occupants as they come in contact with it. These adjustments allow the system to deploy the airbag with a moderate force for most collisions; reserving the maximum force airbag only for the severest of collisions. Additional sensors to determine the location, weight or relative size of the occupants may also be used. Information regarding the occupants and the severity of the crash are used by the airbag control unit, to determine whether airbags should be suppressed or deployed, and if so, at various output levels.
[[File:Airbag SEAT Ibiza.jpg|thumb|Post-deployment view of a [[SEAT Ibiza]] airbag]]

==== Post-deployment ====
A chemical reaction produces a burst of nitrogen to inflate the bag. Once an airbag deploys, deflation begins immediately as the gas escapes through vent(s) in the fabric (or, as it is sometimes called, the cushion) and cools. Deployment is frequently accompanied by the release of dust-like particles, and gases in the vehicle's interior (called effluent). Most of this dust consists of [[cornstarch]], [[french chalk]], or [[talcum powder]], which are used to lubricate the airbag during deployment.

Newer designs produce effluent primarily consisting of harmless talcum powder/cornstarch and nitrogen gas. In older designs using an azide-based propellant (usually {{chem2|NaN3}}), varying amounts of [[sodium hydroxide]] nearly always are initially present. In small amounts this chemical can cause minor irritation to the eyes and/or open wounds; however, with exposure to air, it quickly turns into [[sodium bicarbonate]] (baking soda). However, this transformation is not 100% complete, and invariably leaves residual amounts of hydroxide ions from NaOH. Depending on the type of airbag system, [[potassium chloride]] may also be present.

For most people, the only effect the dust may produce is some minor irritation of the throat and eyes. Generally, minor irritations only occur when the occupant remains in the vehicle for many minutes with the windows closed and no ventilation. However, some people with [[asthma]] may develop a potentially lethal asthmatic attack from inhaling the dust.

Because of the airbag exit flap design of the steering wheel boss and dashboard panel, these items are not designed to be recoverable if an airbag deploys, meaning that they have to be replaced if the vehicle has not been [[total loss|written off]] in a collision. Moreover, the dust-like particles and gases can cause irreparable cosmetic damage to the dashboard and upholstery, meaning that minor collisions that result in the deployment of airbags can be costly, even if there are no injuries and there is only minor damage to the vehicle structure.

== Regulatory specifications ==

=== United States ===
On 11 July 1984, the United States government amended [[FMVSS 208|Federal Motor Vehicle Safety Standard 208]] (FMVSS 208) to require cars produced after 1 April 1989 to be equipped with a passive restraint for the driver. An airbag or an [[Seat belt#Automatic|automatic seat belt]] would meet the requirements of the standard. Airbag introduction was stimulated by the [[National Highway Traffic Safety Administration]].<ref>{{cite web |url= http://www-nrd.nhtsa.dot.gov/pdf/nrd-01/Esv/esv16/98S8P12.PDF |first=Byron |last=Bloch |title=Advanced designs for side impact and rollover protection |work=NHTSA |year=1998 |access-date=16 March 2014 |url-status=dead |archive-url= https://web.archive.org/web/20141125063517/http://www-nrd.nhtsa.dot.gov/pdf/nrd-01/Esv/esv16/98S8P12.PDF |archive-date=25 November 2014 }}</ref> However, airbags were not mandatory on light trucks until 1997.<ref>{{cite web|url= http://www.nhtsa.gov/cars/rules/import/fmvss/index.html#SN208 |title=Federal Motor Vehicle Safety Standards and Regulations (Standard No. 208) |work=NHTSA |date=March 1999 |access-date=16 March 2014 |url-status=live |archive-url= https://web.archive.org/web/20140507031818/http://www.nhtsa.gov/cars/rules/import/FMVSS/index.html |archive-date=7 May 2014 }}</ref>

In 1998, FMVSS 208 was amended to require dual front airbags, and reduced-power, second-generation airbags were also mandated. This was due to the injuries caused by first-generation airbags, though FMVSS 208 continues to require that bags be engineered and calibrated to be able to "save" the life of an ''unbelted'' 50th-percentile size and weight "male" [[crash test dummy]]. The technical performance and validation requirements for the inflator assembly used in airbag modules are specified in [[SAE International|SAE]] USCAR 24–2.<ref>{{cite web|url= http://standards.sae.org/uscar24-2/ |title=USCAR24-22: Inflator Technical Requirements and Validation |publisher=SAE International |date=30 April 2013 |access-date=16 March 2014 |url-status=live |archive-url= https://web.archive.org/web/20140106140336/http://standards.sae.org/uscar24-2/ |archive-date=6 January 2014 }}</ref>

=== Europe ===
Some countries outside North America adhere to internationalized European [[ECE regulations|ECE vehicle and equipment regulations]] rather than the United States Federal Motor Vehicle Safety Standards. ECE airbags are generally smaller and inflate less forcefully than United States airbags because the ECE specifications are based on ''belted'' crash test dummies.

The [[Euro NCAP]] vehicle safety rating encourages manufacturers to take a comprehensive approach to occupant safety; a good rating can only be achieved by combining airbags with other safety features.<ref name=ncap>[http://www.euroncap.com/tests/frontimpact.aspx Frontal impact test description] {{webarchive|url= https://web.archive.org/web/20080506093253/http://www.euroncap.com/tests/frontimpact.aspx |date=6 May 2008 }} Euro NCAP website</ref> Almost every new car sold in Europe is equipped with front and side airbags, but in the [[European Union]] in 2020<ref>{{cite web|url= https://ec.europa.eu/transport/road_safety/specialist/knowledge/vehicle/safety_design_needs/cars_en |title=Cars|date=17 October 2016}}</ref> and in the [[United Kingdom]], and most other developed countries there is no direct legal requirement for new cars to feature airbags.

=== Central and South America ===
Ecuador requires dual front airbags in new car models since 2013.<ref>{{cite web|url= https://www.elcomercio.com/actualidad/negocios/nuevo-reglamento-de-calidad-vehiculos.html|title=Nuevo reglamento de calidad para vehículos|first=Grupo El|last=Comercio|date=January 20, 2014 |work=El Comercio}}</ref>

Since January 2014, except for micro vehicles, all new cars made or imported in Argentina must have front airbags.<ref>{{cite web|url= https://www.lacapital.com.ar/edicion-impresa/airbags-y-abs-sistemas-obligatorios-argentina-n605371.html |title=Airbags y ABS, sistemas obligatorios en Argentina |work=La Capital |language=es |access-date=July 18, 2022}}</ref>

Since 1 January 2014, all new cars sold in Brazil must have dual front airbags.<ref>{{cite web|url= http://g1.globo.com/carros/noticia/2014/01/comeca-valer-obrigatoriedade-de-airbag-e-abs-para-carros-novos.html|archive-url=https://web.archive.org/web/20140102100521/http://g1.globo.com/carros/noticia/2014/01/comeca-valer-obrigatoriedade-de-airbag-e-abs-para-carros-novos.html|url-status=dead|title=Começa a valer obrigatoriedade de airbag e ABS para carros novos|series=G1|location=São Paulo|date=1 January 2014|archive-date=2 January 2014|work=Auto Esporte}}</ref>

Since July 2014, all new cars sold in Uruguay must have dual front airbags.<ref>{{cite web|url= https://www.autoblog.com.uy/2014/07/todo-lo-que-hay-que-saber-de-la-ley-n.html |title=Todo lo que hay que saber de la ley Nº 19.061 |website=autoblog.com.uy}}</ref>

Since December 2016, all new cars sold in Chile must have dual front airbags.<ref>{{cite web|url= https://noticias.autocosmos.cl/2015/03/19/doble-airbag-sera-obligatorio-en-chile |title=Doble Airbag: Será obligatorio en Chile |date=19 March 2015 |website=autocosmos.cl |author1=Autocosmos }}</ref>

Since 1 January 2017, all cars made or imported in Colombia must have dual front airbags.<ref>{{cite web|url= https://www.eltiempo.com/archivo/documento/CMS-16397843|title=Con bolsas de aire, el país se pone a tono con el mundo|first=Casa Editorial El|last=Tiempo|date=7 October 2015 |work=El Tiempo}}</ref>

Since 1 January 2020, all new cars sold in Mexico must have dual front airbags.<ref>{{cite web|url= https://www.eleconomista.com.mx/empresas/Mayor-proteccion-en-los-autos-la-nueva-normatividad-en-la-industria-20191019-0017.html |title=Mayor protección en los autos, la nueva normatividad en la industria|first=Marcos|last=Martínez |work=El Economista}}</ref>

=== India ===
On 5 March 2021, the Indian [[Ministry of Road Transport and Highways]] mandated that all new vehicle models introduced in India after 1 April 2021 have dual front airbags; the regulation also requires that all existing models be equipped with dual front airbags by 31 August 2021.<ref>{{cite web |title=Dual airbags mandatory for new cars from April 1- Business News |url= https://www.businesstoday.in/sectors/auto/dual-airbags-mandatory-for-new-cars-from-april-1/story/433122.html |website=businesstoday.in |date=5 March 2021 |access-date=6 March 2021}}</ref>
India also mandated that all passenger vehicles sold after October 2023 must have a minimum of six airbags.<ref>{{cite news |url= https://www.ndtv.com/india-news/6-airbag-rule-for-passenger-cars-to-come-into-force-in-october-next-year-says-nitin-gadkari-3388205 |title=6 Airbags In Cars A Must From October 2023 |first= Akhilesh |last=Sharma |work=New Delhi TV |location=India |date=29 September 2022 |access-date=2 October 2022}}</ref>

== Maintenance ==
{{Globalize|section|date=September 2008}}
Inadvertent airbag deployment while the vehicle is being serviced can result in severe injury, and an improperly installed or defective airbag unit may not operate or perform as intended. Those servicing a vehicle, as well as first responders, must exercise extreme awareness, as many airbag control systems may remain powered for roughly 30 minutes after disconnecting the vehicle's battery.{{r|MCFRS|p=3}} Some countries impose restrictions on the sale, transport, handling, and service of airbags and system components. In [[Germany]], airbags are regulated as harmful explosives; only [[Auto mechanic|mechanics]] with special training are allowed to service airbag systems.

Some automakers (such as [[Mercedes-Benz]]) call for the replacement of undeployed airbags after a certain time to ensure their reliability in a collision. One example is the 1992 S500, which has an expiry date sticker attached to the door pillar. Some [[Škoda Auto|Škoda]] vehicles indicate an expiry date of 14 years from the date of manufacture. In this case, replacement would be uneconomic as the car would have negligible value at 14 years old, far less than the cost of fitting new airbags. [[Volvo]] has stated that "airbags do not require replacement during the lifetime of the vehicle," though this cannot be taken as a guarantee on the device.<ref name=BohrAAA>{{citation|last=Bohr |first=Peter |date=July–August 2010 |title=Air Time |periodical=AAA World |volume=12 |issue=4 |page=24 }}</ref>

== Limitations ==
[[File:Underride guard full-width impact test.JPG|thumb|[[Crash test]] of an [[underride guard]] at {{cvt|30|-|40|kph}}—the truck platform at head height has been prevented from impacting the [[windshield]].]]

Although the millions of installed airbags in use have an excellent safety record, some limitations on their ability to protect car occupants exist. The original implementation of front airbags did little to protect against [[side collision]]s, which can be more dangerous than frontal collisions because the protective [[crumple zone]] in front of the passenger compartment is completely bypassed. Side airbags and protective airbag curtains are increasingly being required in modern vehicles to protect against this very common category of collisions.

Airbags are designed to deploy once only, so are ineffective if any further collisions occur after an initial impact. Multiple impacts may occur during rollovers or other incidents involving multiple collisions, such as many [[multi-vehicle collision|multivehicle collision]]s.<ref name=Hyundai>{{cite web |url= http://www.hsguide.net/curtain_air_bag-698.html |title=Curtain air bag Hyundai Sonata: Manuals and Car Information |website=hsguide.net |access-date=7 June 2014 |url-status=live |archive-url= https://web.archive.org/web/20140714152107/http://www.hsguide.net/curtain_air_bag-698.html |archive-date=14 July 2014 }}</ref>

An extremely dangerous situation occurs during "[[underride collision]]s", in which a passenger vehicle collides with the rear of a [[tractor-trailer]] lacking a rear underride guard, or hits the side of such a trailer not equipped with a side underride guard.<ref name=Underride>{{cite web|title=Getting Started |url= http://www.underridenetwork.org |website=underridenetwork.org |access-date=7 June 2014 |url-status=deviated |archive-url= https://web.archive.org/web/20140714205447/http://www.underridenetwork.org/ |archive-date=14 July 2014 }}</ref> The platform bed of a typical trailer is roughly at the head height of a seated adult occupant of a typical passenger car. This means not much of a barrier exists between a head and the edge of the trailer platform, except a glass [[windshield]].<ref>[http://www.everything2.com/index.pl?node_id=1679241 Underride Guard on Everything2] {{webarchive|url=https://web.archive.org/web/20080315092016/http://www.everything2.com/index.pl?node_id=1679241 |date=15 March 2008 }}; Retrieved: 29 November 2007</ref> In an underride collision, the car's [[crush zone]]s designed to absorb collision energy are completely bypassed, and the airbags may not deploy in time because the car does not decelerate appreciably until the windshield and roof pillars have already impacted the trailer bed.<ref name="Hyundai" /> Even delayed inflation of airbags may be useless because of major intrusion into the passenger space, leaving occupants at high risk of major [[head trauma]] or [[decapitation]] in even low-speed collisions. Western European standards for underride guards have been stricter than North American standards, which typically have allowed [[grandfathering]] of older equipment that may still be on the road for decades.<ref name="Underride" /><ref>{{cite book |last=United States Congressional Committee on Commerce |title=Reauthorization of the National Highway Traffic Safety Administration |year=1997 |page=39}}</ref>

Typical airbag systems are completely disabled by turning off the [[ignition key]]. Unexpected turnoffs usually also disable the engine, [[power steering]], and [[power brakes]], and can be the direct cause of a collision. If a violent collision occurs, the disabled airbags will not deploy to protect vehicle occupants. In 2014, [[2014 General Motors recall|General Motors admitted to concealing information]] about fatal collisions caused by defective ignition switches that would abruptly shut down a car (including its airbags). Between 13 and 74 deaths have been directly attributed to this defect, depending on how the fatalities are classified.<ref>{{cite magazine|url= https://time.com/2819690/gm-recall-deaths-ignition-switch/ |title=GM Disputes Report Tying Ignition Switch Problem to 74 Deaths |magazine=Time |date=3 June 2014 |access-date=4 June 2014 |last=Feeney |first=Nolan |url-status=live |archive-url= https://web.archive.org/web/20140603232322/http://time.com/2819690/gm-recall-deaths-ignition-switch/ |archive-date=3 June 2014}}</ref>

== Injuries and fatalities ==
[[File:Lives Saved by Safety Belts and Air Bags, NHTSA, DOT.svg|thumb|Lives saved by [[seat belt]]s and airbags in the United States of America over 10 years]]

Under some rare conditions, airbags can injure and in some very rare instances kill vehicle occupants. To provide crash protection for occupants not wearing seat belts, United States airbag designs trigger much more forcefully than airbags designed to the international ECE standards used in most other countries. Recent "smart" airbag controllers can recognize if a seat belt is used, and alter the airbag cushion deployment parameters accordingly.<ref>{{cite web |url= http://www.nhtsa.gov/cars/rules/rulings/AAirBagSNPRM/#snprm7 |title=NHTSA 49 CFR Parts 552, 571, 585, and 595, Docket Notice |work=NHTSA |date=1 December 2000 |access-date=16 March 2014 |url-status=live |archive-url= https://web.archive.org/web/20140316225152/http://www.nhtsa.gov/cars/rules/rulings/AAirBagSNPRM/ |archive-date=16 March 2014}}</ref>

In 1990, the first automotive fatality attributed to an airbag was reported.<ref name="NHTSAAirBag">{{cite web|url= http://www.nsc.org/partners/status3.htm |archive-url= https://web.archive.org/web/20080226234316/http://www.nsc.org/partners/status3.htm |archive-date=26 February 2008 |title=Statistical Breakdown of Air Bag Fatalities |publisher=National Highway Traffic Safety Administration |access-date=16 March 2014}}</ref> [[TRW Inc.|TRW]] produced the first gas-inflated airbag in 1994, with sensors and low inflation-force bags becoming common soon afterward. Dual-depth (also known as dual-stage) airbags appeared on passenger cars in 1998. By 2005, deaths related to airbags had declined, with no adult deaths and two child deaths attributed to airbags that year. However, injuries remain fairly common in collisions with airbag deployment.

Serious injuries are less common, but severe or fatal injuries can occur to vehicle occupants very near an airbag or in direct contact when it deploys. Such injuries may be sustained by unconscious drivers slumped over the steering wheel, unrestrained or improperly restrained occupants who slide forward in the seat during precrash braking, and properly belted drivers sitting very close to the steering wheel. A good reason for the driver not to cross hands over the steering wheel, a rule taught to most learner drivers, but quickly forgotten by most, is that an airbag deployment while negotiating a turn may result in the driver's hand(s) being driven forcefully into their face, exacerbating any injuries from the airbag alone.

A US study showed that the risk for a serious [[head injury]] occurring is 5.495% while travelling {{cvt|25-30|mph|0|order=flip}}. The risk is reduced for passengers to 4.435%. This risk is lowered by 80.5% to 1.073% when using an airbag. The risk for passengers is lowered by 82% to 0.797%. The tests with the airbags were done at {{cvt|35|mph|0|order=flip}}, {{cvt|5-10|mph|0|order=flip}} faster than the tests without air bags. There is a 15.45% risk of serious injury to unprotected occupants at {{cvt|30-35|mph|0|order=flip}}, this drops to 4.68% with protected occupants. This is a 69.7% decrease in change of serious injury, with the airbags deploying 96.1% of the time.<ref>{{Cite journal |last=Viano |first=David C. |date=2024-04-02 |title=History of airbag safety benefits and risks |url=https://www.tandfonline.com/doi/full/10.1080/15389588.2024.2315889 |journal=Traffic Injury Prevention |volume=25 |issue=3 |pages=268–287 |doi=10.1080/15389588.2024.2315889 |issn=1538-9588 |pmid=38408114|url-access=subscription }}</ref>

Improvements in sensing and gas-generator technology have allowed the development of third-generation airbag systems that can adjust their deployment parameters to the size, weight, position, and restraint status of the occupant. These improvements have demonstrated a reduced injury risk factor for small adults and children, who had an increased risk of injury with first-generation airbag systems.<ref>{{Cite journal |journal=American Journal of Epidemiology |title=Association of First- and Second-Generation Airbags with Front Occupant Death in Car Crashes: A Matched Cohort Study |first1=Carin M. |last1=Olson |first2=Peter |last2=Cummings |first3=Frederick P. |last3=Rivara |volume=164 |issue=2|pages=161–9|doi=10.1093/aje/kwj167 |pmid=16775043 |year=2006 }}</ref>

One model of airbags made by the [[Takata Corporation]] used [[ammonium nitrate]]–based gas-generating compositions in airbag inflators instead of the more stable, but more expensive compound [[tetrazole]]. The ammonium nitrate-based inflators have a flaw where old inflators with long-term exposure to hot and humid climate conditions could rupture during deployment, projecting metal shards through the airbag and into the driver.<ref>{{cite web|url= http://icsw.nhtsa.gov/safercar/rs/takata/takata-presscon110315.html |title=NHTSA Recalls Spotlight – Takata Air Bag Recalls – November 3, 2015 Press Conference |work=nhtsa.gov |url-status=dead |archive-url= https://web.archive.org/web/20160102080537/http://icsw.nhtsa.gov/safercar/rs/takata/takata-presscon110315.html |archive-date=2 January 2016}}</ref> As of December 2022, the defect has caused 33 deaths worldwide, with up to 24 in the U.S. and the remaining in Australia and Malaysia.<ref>{{cite news|url=https://apnews.com/article/business-takata-corp-government-and-politics-53787c88a25cac65fe678c3b06db8c5c|title=US reports another Takata air bag death, bringing toll to 33|first=Tom|last=Krishner|date=December 9, 2022|work=[[Associated Press]]}}</ref> The [[National Highway Traffic Safety Administration]] (NHTSA) recalled over 33 million vehicles in May 2015,<ref>{{cite news|url=https://www.theguardian.com/business/2015/may/19/takata-air-bag-defect-largest-auto-recall-us-history |title=Air bag defect to trigger largest auto recall in US history |access-date=10 December 2016 |url-status=live |archive-url= https://web.archive.org/web/20160808091220/https://www.theguardian.com/business/2015/may/19/takata-air-bag-defect-largest-auto-recall-us-history |archive-date=8 August 2016 |newspaper=The Guardian |date=19 May 2015 |last1=Rushe |first1=Dominic}}</ref> and fined Takata $70 million in November 2015.<ref>{{cite news|title=Takata fined $70 million for defective airbags as recalls nearly double |url= https://www.latimes.com/business/la-fi-takata-airbags-20151103-story.html |newspaper=LA Times |access-date=3 November 2015 |url-status=live |archive-url= https://web.archive.org/web/20151103215651/http://www.latimes.com/business/la-fi-takata-airbags-20151103-story.html |archive-date=3 November 2015}}</ref> Toyota, Mazda, and Honda have said that they will not use ammonium-nitrate inflators.<ref>{{cite web|url= http://fortune.com/2015/11/06/takatas-woes-are-complete-now-toyota-has-dropped-it/ |title=Takata's Woes Are Complete: Now Toyota Has Dropped It |work=Fortune |url-status=live |archive-url= https://web.archive.org/web/20151109005934/http://fortune.com/2015/11/06/takatas-woes-are-complete-now-toyota-has-dropped-it/ |archive-date=9 November 2015}}</ref><ref>{{cite web|url= http://bigstory.ap.org/article/a59ec1a2350b40a5bbddfde18399d7e1/japan-air-bag-maker-takata-reports-46-million-loss |title=Japan air bag maker Takata reports $46 million loss |work=The Big Story |url-status=live |archive-url= https://web.archive.org/web/20160102080537/http://bigstory.ap.org/article/a59ec1a2350b40a5bbddfde18399d7e1/japan-air-bag-maker-takata-reports-46-million-loss |archive-date=2 January 2016}}</ref> In June 2017, Takata filed for bankruptcy.<ref>{{cite web|url=https://money.cnn.com/2017/06/25/news/companies/takata-bankruptcy/index.html|title=Takata, brought down by airbag crisis, files for bankruptcy|date=25 June 2017|publisher=CNN}}</ref>

=== Airbag fatality statistics ===
From 1990 to 2000, the United States NHTSA identified 175 fatalities caused by airbags. Most of these (104) have been children. About 3.3 million airbag deployments have occurred during that interval, and the agency estimates more than 6,377 lives were saved and countless injuries were prevented.<ref name="NHTSAAirBag" /><ref name=BohrAAA2>The statement "they've saved some 26,000 lives, according to estimates from the ... (NHTSA)" has been published. {{Citation| last = Bohr | first = Peter |date=July–August 2010 |title=Air Time |periodical=AAA World |volume=12 |issue=4 |page=24}}</ref>

A rear-facing infant restraint put in the front seat of a vehicle places an infant's head close to the airbag, which can cause severe [[head injury|head injuries]] or death if the airbag deploys. Some modern cars include a switch to disable the front-passenger airbag, in case a child-supporting seat is used there (although not in Australia, where rear-facing child seats are prohibited in the front where an airbag is fitted).

In vehicles with side airbags, it is dangerous for occupants to lean against the windows, doors, and pillars, or to place objects between themselves and the side of the vehicle. Articles hung from a vehicle's clothes hanger hooks can be hazardous if the vehicle's side-curtain airbags are deployed.<ref>Toyota Aurion: User Manual 2006 model – Australia</ref> A seat-mounted airbag may also cause internal injury if the occupant leans against the door.<ref>{{cite journal |pmid=20184829 |volume=53 |title=Splenic trauma as an adverse effect of torso-protecting side airbags: biomechanical and case evidence |date=Oct 2009 | journal=Ann Adv Automot Med |pages=13–24 |pmc=3256804 |last1=Hallman |first1=J.J. |last2=Brasel |first2=K.J. |last3=Yoganandan |first3=N. |last4=Pintar |first4=F.A.}}</ref><ref>{{cite journal |pmid=21512911 |volume=54 |title=Biomechanical and injury response to posterolateral loading from torso side airbags |date=November 2010 |journal=Stapp Car Crash J |pages=227–57 |pmc=3820120 |last1=Hallman |first1=J.J. |last2=Yoganandan |first2=N. |last3=Pintar |first3=F.A. |series=SAE Technical Paper Series |article-number=2010-22-0012 |doi=10.4271/2010-22-0012 }}</ref>

== Aerospace and military applications ==
The [[aerospace]] industry and the [[Federal government of the United States|United States government]] have applied airbag technologies for many years. [[NASA]] and [[United States Department of Defense]] have incorporated airbag systems in various aircraft and spacecraft applications as early as the 1960s.

=== Spacecraft airbag landing systems ===
[[File:Pathfinder Air Bags - GPN-2000-000484.jpg|thumb|NASA engineers test the [[Mars Pathfinder]] airbag [[landing]] system on simulated Martian terrain]]
The first use of airbags for [[landing]] were [[Luna 9]] and [[Luna 13]]. As with later missions, these would use the airbags to bounce along the surface, absorbing landing energy. The [[Mars Pathfinder]] lander employed an innovative airbag landing system, supplemented with [[aerobraking]], [[parachute]], and [[solid rocket]] landing thrusters. This prototype successfully tested the concept, and the two [[Mars Exploration Rover Mission]] landers employed similar landing systems. The [[Beagle 2]] Mars lander also tried to use airbags for landing; the landing was successful, and the lander touched down safely, but several of the spacecraft's solar panels failed to deploy, thereby disabling the spacecraft.

The [[Boeing Starliner]] uses six airbags to cushion the ground landing of the crewed capsule.<ref>{{Cite web |title=NASA's Boeing Crew Flight Test Mission Overview |url=https://www.nasa.gov/nasas-boeing-crew-flight-test-mission-overview/ |access-date=2024-06-01 |website=NASA |language=en-US}}</ref>

=== Aircraft airbag landing systems ===
Airbags have also been used on military fixed-wing aircraft, such as the [[Escape crew capsule#Design and development|escape crew capsule]] of the [[F-111 Aardvark]].

=== Occupant protection ===
[[File:OH-58D Cockpit Air Bag System (CABS).jpg|thumb|OH-58D CABS test]]

The [[United States Army]] has incorporated airbags in its [[UH-60 Black Hawk|UH-60A/L]]<ref>{{cite web|url= http://www.defense.gov/contracts/contract.aspx?contractid=1462 |title=Defenselink article |website=defense.gov |date=18 February 1999 |url-status=dead |archive-url= https://web.archive.org/web/20140316224540/http://www.defense.gov/contracts/contract.aspx?contractid=1462 |archive-date=16 March 2014}}</ref><ref>{{cite news|url= https://www.helis.com/database/news/air-bag-hawk/ |title=Cockpit Air Bag System (CABS) for UH-60A/L |work=helis.com |date=18 November 1999 |access-date=15 January 2020}}</ref> Black Hawk and [[OH-58 Kiowa|OH-58D]] Kiowa Warrior<ref>{{cite web|url= http://www.fas.org/man/dod-101/sys/ac/oh-58.htm |title=OH-58D Kiowa Warrior |website=fas.org |date=29 May 2000 |access-date=16 March 2014 |url-status=live |archive-url= https://web.archive.org/web/20061014035814/http://www.fas.org/man/dod-101/sys/ac/oh-58.htm |archive-date=14 October 2006 }}</ref> helicopter fleets. The Cockpit Air Bag System (CABS)<ref>{{cite web|url= http://www.tslaerospace.com/product/simula/PDF/CABS%20Sunset%20Brochure.pdf |title=Microsoft Word - Sunset Brochure.doc |access-date=17 October 2010 |url-status=dead |archive-url= https://web.archive.org/web/20050913064647/http://www.tslaerospace.com/product/simula/PDF/CABS%20Sunset%20Brochure.pdf |archive-date=13 September 2005 }}</ref> consists of forward and lateral airbags, and an inflatable tubular structure (on the OH-58D only) with an Electronic Crash Sensor Unit (ECSU). The CABS system was developed by the United States Army [[Aviation Applied Technology Directorate]], through a contract with Simula Safety Systems (now [[BAE Systems]]).<ref>{{cite web|url= http://csat.au.af.mil/2025/concepts/900312.HTM |title=Air Defense concept papers |website=csat.au.af.mil |access-date=17 October 2010 |url-status=dead |archive-url= https://web.archive.org/web/20100812011816/http://csat.au.af.mil/2025/concepts/900312.HTM |archive-date=12 August 2010 }}</ref> It is the first conventional airbag system for occupant injury prevention (worldwide) designed and developed and placed in service for an aircraft, and the first specifically for helicopter applications.<ref>{{cite web |url=http://findarticles.com/p/articles/mi_m0EIN/is_2002_June_13/ai_87142543 |archive-url=https://web.archive.org/web/20101203134025/http://findarticles.com/p/articles/mi_m0EIN/is_2002_June_13/ai_87142543/ |url-status=dead |archive-date=3 December 2010 |title=BNET News Release on AHS Annual Forum award |website=findarticles.com |date=13 June 2002 |access-date=17 October 2010 }}</ref><ref>{{cite web|url= http://www.allbusiness.com/government/government-bodies-offices-government/5706607-1.html |title=Simula Receives Orders for its Cockpit Air Bag Systems - CABS |archive-url= https://web.archive.org/web/20100522002505/http://www.allbusiness.com/government/government-bodies-offices-government/5706607-1.html |publisher=allbusiness.com |archive-date=22 May 2010 |access-date=15 January 2020}}</ref>

== Other uses ==
In the mid-1970s, the UK [[Transport Research Laboratory]] tested several types of [[motorcycle airbag]]s. In 2006 [[Honda]] introduced the first production [[motorcycle]] airbag safety system on its [[Gold Wing]] motorcycle. Honda claims that sensors in the front forks can detect a severe frontal collision and decide when to deploy the airbag, absorbing some of the forward energy of the rider and reducing the velocity at which the rider may be thrown from the motorcycle.<ref>{{cite web |url= http://www.motorcyclenews.com/MCN/News/newsresults/archive/86493/86922/86926/86935/?&R=EPI-86935 |work=Motorcycle News |location=UK |archive-url= https://web.archive.org/web/20090212163755/http://www.motorcyclenews.com/MCN/News/newsresults/archive/86493/86922/86926/86935/?&R=EPI-86935 |archive-date=12 February 2009 |title='06 Wing gets airbag |date=2 September 2005}}</ref>

More commonly, [[air bag vest]]s – either integrated into the motorcyclist's jacket or worn over it – have started to become used by regular riders on the street.<ref>{{Cite web|url=https://www.motorcyclenews.com/news/new-tech/motorbike-airbag-vests/|title = Exploding the myths: Everything you need to know about motorbike airbag vests |first=Emma |last=Franklin |work=Motorcycle News |location=UK |date=2021-10-08 |access-date=2023-07-24}}</ref> [[MotoGP]] has made it compulsory since 2018 for riders to wear suits with integrated airbags.<ref>{{Cite web |url=https://www.motogp.com/en/news/2017/12/21/airbags-compulsory-from-2018/247973 |title=Airbags: Compulsory from 2018 |work=MotoGP |date=2017-12-21 |access-date=2023-07-24}}</ref>

Similarly, companies such as Helite and Hit-Air have commercialized equestrian airbags, which attach to the saddle and are worn by the rider. Other sports, particularly skiing and snowboarding, have started introducing airbag safety mechanisms.<ref>{{Cite web |last=Whitling |first=Cy |date=2023-10-27 |title=An Introduction to Airbag Packs |url=https://www.powder.com/gear/an-introduction-to-airbag-packs |access-date=2024-12-10 |website=www.powder.com |language=en}}</ref>

<gallery widths="200px" heights="155px">
File:Airbag backpack, IAA 2021, Munich (IAA10362).webm|Airbag for cycling
File:Motorradairbag.JPG|Airbag on a motorcycle
</gallery>

== See also ==
{{Div col|colwidth=23em}}
* [[Airbag dermatitis]]
* [[Airplane airbags]]
* [[Air suspension]]
* [[List of auto parts]]
* [[Precrash system]]
* [[Safety standards]]
{{div col end}}

== References ==
{{Reflist|refs=
<ref name="TRB-report">{{cite report |first1=Hampton C. |last1=Gabler |first2=Douglas J. |last2=Gabauer |first3=Heidi L. |last3=Newell |first4=Michael E. |last4=O’Neill |date=Dec 2004 |title=Use of Event Data Recorder (EDR) Technology for Highway Crash Data Analysis |url= https://www.nhtsa.gov/sites/nhtsa.dot.gov/files/edr_technology.pdf |publisher=Transportation Research Board of the National Academies |access-date=2020-02-22}}</ref>
<ref name="MCFRS">{{cite report |author=((Montgomery County Fire & Rescue)) |title=MCFRS Driver Certification Program: Vehicle Safety |url= https://www.montgomerycountymd.gov/mcfrs-psta/Resources/Files/Driver/20150325/UnitKBRescueSquads/RescueSquad_Manual/Resource_Guide/Module_12_Vehicle_Safety.pdf |publisher=Montgomery Maryland County Government |access-date=2020-02-22}}</ref>
}}

== External links ==
{{Commons category|Air bags|Airbags}}
* [https://web.archive.org/web/20051102080256/http://www.chemistry.wustl.edu/~edudev/LabTutorials/Airbags/airbags.html Chemistry behind airbags]
* [https://web.archive.org/web/20090421143843/http://www.cardomain.com/ride/770691/3 Pictures and details about the 1970s GM Air Cushion Restraint System]
* {{cite web|last=Magratten |first=Drew |title=The Promise of the Air Bag |url= https://www.retroreport.org/video/the-promise-of-the-air-bag |publisher=Retro Report |date=14 September 2014 |access-date=4 April 2018}} History of airbags and how the technology gave rise to today's "smart cars".

{{Car-interior}}
{{Authority control}}

[[Category:Airbags| ]]
[[Category:1973 introductions]]
[[Category:20th-century inventions]]
[[Category:Aircraft emergency systems]]
[[Category:American inventions]]
[[Category:Bags]]
[[Category:Vehicle parts]]
[[Category:Vehicle safety technologies]]