Editing Seat belt (section)

==Legislation==
{{Main |Seat belt legislation}}

In observational studies of [[car crash]] morbidity and mortality,<ref name=nakahara>{{cite journal |vauthors=Nakahara S, Ichikawa M, Wakai S |title=Seatbelt legislation in Japan: high risk driver mortality and seatbelt use |journal=Inj. Prev. |volume=9 |issue=1 |pages=29–32 |year=2003 |pmid=12642555 |doi = 10.1136/ip.9.1.29 |pmc=1730910}}</ref><ref>{{Cite journal |vauthors=Allen S, Zhu S, Sauter C, Layde P, Hargarten S |title=A comprehensive statewide analysis of seatbelt non-use with injury and hospital admissions: new data, old problem |journal=Academic Emergency Medicine |volume=13 |issue=4 |pages=427–34 |year=2006 |pmid=16531597 |doi=10.1197/j.aem.2005.11.003 |doi-access=free }}</ref><ref>{{Cite journal |vauthors=Bourbeau R, Desjardins D, Maag U, Laberge-Nadeau C |title=Neck injuries among belted and unbelted occupants of the front seat of cars |journal=The Journal of Trauma |volume=35 |issue=5 |pages=794–799 |year=1993 |pmid=8230348 |doi=10.1097/00005373-199311000-00024}}</ref> [[experiment]]s using both [[crash test dummy|crash test dummies]] and human [[cadaver]]s indicate that wearing seat belts greatly reduces the risk of [[death]] and injury in the majority of car crashes.

This has led many countries to adopt mandatory seat belt wearing laws. It is generally accepted that, in comparing like-for-like accidents, a vehicle occupant not wearing a properly fitted seat belt has a significantly and substantially higher chance of death and serious injury. One large observation studying using U.S. data showed that the [[odds ratio]] of crash death is 0.46 with a three-point belt when compared with no belt.<ref>{{Cite journal |vauthors=Bédard M, Guyatt GH, Stones MJ, Hirdes JP |title=The independent contribution of driver, crash, and vehicle characteristics to driver fatalities |journal=[[Accident Analysis & Prevention]] |volume=34 |issue=6 |pages=717–27 |year=2002 |pmid=12371777 |doi = 10.1016/S0001-4575(01)00072-0}}</ref> In another study that examined injuries presenting to the [[emergency room|ER]] pre- and post-seat belt law introduction, it was found that 40% more escaped injury and 35% more escaped mild and moderate injuries.<ref>{{Cite journal |vauthors=Thomas J |title=Road traffic accidents before and after seatbelt legislation--study in a district general hospital |journal=Journal of the Royal Society of Medicine |volume=83 |issue=2 |pages=79–81 |year=1990 |pmid=2319551 |pmc=1292501|doi=10.1177/014107689008300207 }}</ref>

The effects of seat belt laws are disputed by those who observe that their passage did not reduce road fatalities. There has also been concern that instead of legislating for a general protection standard for vehicle occupants, laws that required a particular technical approach would rapidly become dated as motor manufacturers would tool up for a particular standard that could not easily be changed. For example, in 1969 there were competing designs for lap and three-point seat belts, rapidly tilting seats, and airbags being developed. As countries started to mandate seat belt restraints the global auto industry invested in the tooling and standardized exclusively on seat belts, and ignored other restraint designs such as airbags for several decades<ref>{{cite news |newspaper = The Times |date = 1969-01-24 |title = Safety Design |first = John |last = Fenton }}</ref>

As of 2016, seat belt laws can be divided into two categories: primary and secondary. A primary seat belt law allows an officer to issue a citation for lack of seat belt use without any other citation, whereas a secondary seat belt law allows an officer to issue a seat belt citation only in the presence of a different violation. In the United States, fifteen states enforce secondary laws, while 34 states, as well as the District of Columbia, American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the Virgin Islands enforce primary seat belt laws. New Hampshire lacks either a primary or secondary seat belt law.<ref>{{cite web |title=State Seat Belt Laws |url=http://www.ghsa.org/html/stateinfo/laws/seatbelt_laws.html |website=ghsa.org |access-date=2016-02-15 |archive-date=2018-12-25  |archive-url=https://web.archive.org/web/20181225135730/https://www.ghsa.org/html/stateinfo/laws/seatbelt_laws.html%20 |url-status=dead }}</ref>

===Risk compensation===
Some have proposed that the number of deaths was influenced by the development of [[risk compensation]], which says that drivers adjust their behavior in response to the increased sense of personal safety wearing a seat belt provides.

In one trial subjects were asked to drive [[go-kart]]s around a track under various conditions. It was found that subjects who started driving unbelted drove consistently faster when subsequently belted.<ref>{{Cite journal |vauthors=Streff FM, Geller ES |title=An experimental test of risk compensation: between-subject versus within-subject analyses |journal=Accident Analysis & Prevention |volume=20 |issue=4 |pages=277–87 |year=1988 |pmid=3415759 |doi=10.1016/0001-4575(88)90055-3 |url= https://deepblue.lib.umich.edu/bitstream/2027.42/27199/1/0000202.pdf |hdl=2027.42/27199 |hdl-access=free }}</ref> Similarly, a study of habitual non-seat belt wearers driving in freeway conditions found evidence that they had adapted to  use by adopting higher driving speeds and closer following distances.<ref>{{cite journal |vauthors=Janssen W |title=Seat-belt wearing and driving behavior: an instrumented-vehicle study |journal=Accident Analysis & Prevention |volume=26 |issue=2 |pages=249–61 |year=1994 |pmid=8198694 |doi = 10.1016/0001-4575(94)90095-7}}</ref>

A 2001 analysis of U.S. crash data aimed to establish the effects of  legislation on driving fatalities<ref name=CohenLeinav/> and found that previous estimates of seat belt effectiveness had been significantly overstated.

According to the analysis, seat belts decreased fatalities by 1.35% for each 10% increase in seat belt use. The study controlled for endogenous motivations of seat belt use, because that creates an artificial correlation between seat belt use and fatalities, leading to the conclusion that seat belts cause fatalities. For example, drivers in high-risk areas are more likely to use seat belts and are more likely to be in accidents, creating a non-causal correlation between seat belt use and mortality. After accounting for the endogeneity of seat belt usage, Cohen and Einav found no evidence that the risk compensation effect makes seat belt-wearing drivers more dangerous, a finding at variance with other research.

===Increased traffic===
Other statistical analyses have included adjustments for factors such as increased traffic and age, and based on these adjustments, which results in a reduction of morbidity and mortality due to seat belt use.<ref name=nakahara/> However,{{Relevance inline|date=June 2019}} [[Smeed's law]] predicts a fall in accident rate with increasing car ownership and has been demonstrated independently of seat belt legislation.{{citation needed|date=June 2019}}