Editing Airbag (section)

== 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>