Seat belt legislation

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Seat belt legislation is a law or laws put in place to enforce or require the wearing of seat belts while person is driving, or there are passengers in the front or back seats. Most western countries have compulsory seat belt laws.

Contents

[edit] Predicted effects

The move towards seat belt legislation started in Australia in the late 1960s, although it was echoed elsewhere. It was influenced primarily by doctors working in emergency medicine, who noted that seat belt wearers were less likely to be seriously injured in collisions[citation needed].

Hospital based case-control studies of crash victims supported the empirical observation that those wearing seat belts were less likely to be killed or seriously injured than those not wearing them. Based on this type of study, predictions such as 45% reductions in fatal injury and 50% reductions in moderate-to-critical injury were made[citation needed]. Experiments using both crash test dummies and actual human cadavers also indicated that wearing seat belts should lead to reduced risk of death and injury in certain types of car crash.

As a result of such predictions the use of seat belts by vehicle occupants was made compulsory in Victoria, Australia in 1970, followed by the rest of Australia and other countries during the 1970s and 1980s. Predicted savings of lives in the thousands or (in the case of the USA) tens of thousands have been the standard currency of seat belt legislation proponents.

Successive U.K. Governments proposed, but failed to deliver, seat belt wearing legislation throughout the 1970s[1]. In one such attempt in 1978 similar claims for potential lives and injuries saved were advanced. William Rodgers, then Secretary of State for Transport in the Callaghan Labour Government (1976–1979), stated that: [citation needed]

On the best available evidence of accidents in this country - evidence which has not been seriously contested - compulsion could save up to 1000 lives and 10,000 injuries a year.

Professor John Adams of University College London was sceptical of such claims and set out to analyse the effect of seat belt laws as then in force and assess how well they matched predictions. His findings were published in 1982 and can be found in the Society of Automotive Engineers transactions of that year[2]. His conclusion was that in the eighteen countries surveyed, accounting for approximately 80% of the world's motoring, those countries with seat belt laws had fared no better, and in some cases (e.g. Sweden, Ireland and New Zealand) significantly worse than those without. In order to explain this disparity, Adams advanced the hypothesis that Protecting car occupants from the consequences of bad driving encourages bad driving.

It is suggested that a number of mechanisms are in play:

  • Better protected drivers take less care (risk compensation or risk homeostasis).
  • Case-control studies based on voluntary use of safety aids can attribute to the aid benefits that actually come from the risk-averse nature of those likely to use them voluntarily (confounding), particularly early adopters.
  • Fatality rates are subject to considerable stochastic noise and comparison of single years or short periods can be misleading.

There is evidence to support the risk compensation theory. In one experiment[citation needed], two groups of drivers (habitual wearers and habitual non-wearers) were asked to drive a test track under the guise of testing different seat belt materials for comfort. It was observed that the habitually unbelted drivers consistently drove faster and cornered faster when wearing seat belts. Similar effects have been observed in respect of other interventions such as anti-lock brakes. In another, taxi drivers who were habitual non-wearers were timed over a route with passengers who did, and others who did not, insist on the driver wearing a belt. They were observed to complete the route faster when belted.[3]

In response the UK's Department of Transport commissioned a study on the effects of seat belt laws in Sweden, West Germany, Denmark, Spain, Belgium, Finland, the Netherlands and Norway. This study, known as "the Isles report" after its author, used the United Kingdom and Italy as controls for no-law countries compared casualty trends for both those inside and outside cars between law and no-law states. The report predicted that, based on the experiences of the eight countries studied, a UK seat belt law would be followed by a 2.3% increase in fatalities among car occupants[4].

[edit] Measured effects

Initial reports from Australia indicated that the laws had indeed been effective: a rising trend in fatalities pre-1970 had been arrested and reversed, and this was attributed to the effect of seat belt legislation. This attribution did not meet with universal acceptance: introduction of early seat belt laws coincided with the world oil crisis, and other national road safety initiatives. The United Kingdom experienced a reduction in casualties at the same time[5] (British seat belt legislation was not introduced until a decade later), which also coincided with the acclaimed Clunk Click Every Trip campaign to encourage voluntary wearing of seat belts. Claims of the number of lives saved, based on the extrapolation of trends pre-law, could not therefore be reliably associated solely with seat belt compulsion, because so many other factors were also involved[6].

[edit] Non-vehicle occupants

From the very beginning in Australia[7], and subsequently New Zealand[8], there had been indications that seat belt laws might produce increases in deaths and injury among those outside cars such as motorcyclists, cyclists and pedestrians[9] . The author of the Isles report was alarmed to find that in Europe the predominant effect of seat belt legislation was of increased numbers of injuries to non-car users. The author predicted that in the UK, deaths to other road users would rise by approximately 150 per year in the event of compulsory seat belt wearing legislation. In terms of injuries to other road users the prediction was for an 11% increase in pedestrian injuries with injuries to other road users climbing by 12 to 13% (numerically 7,000 and 36,000 respectively).

[edit] The British Law

The Isles report was never published (according to some authorities[4] it was suppressed as it did not back the pre-existing position of Government and the Department), and is known mainly because it was leaked to The Spectator magazine some time after the law was passed. A law was passed which at the same time introduced evidential breath testing.

The law mandating the compulsory wearing of seat belts for front seat occupiers came into force on January 31, 1983 in the UK[10].

There was a reduction in driver fatalities and an increase in fatalities of rear passengers (not covered by the law)[11]. A subsequent study of 19,000 cyclist and 72,000 pedestrian casualties seen at the time suggests that seat belt wearing drivers were 11-13% more likely to injure pedestrians and 7-8% more likely to injure cyclists [12]. In January 1986 an editorial in The Lancet noted the shortfall in predicted life-saving and "the unexplained and worrying increase in deaths of other road users"[13]. Shortly after this, legal compulsion was extended indefinitely.

Rodgers claimed in 1978, prior to his unsuccessful attempt to introduce seat belt compulsion, that "the best evidence" indicated a likely saving of a thousand lives and ten thousand injuries per year. On January 30, 2003, 20 years after the introduction of compulsory front seat belt wearing, the Parliamentary Advisory Council for Transport Safety (PACTS) published their Seat Belts Factsheet[14] which states:

Seat belts are a proven way of reducing the severity of injuries. The government has estimated that since seat belt wearing was made compulsory in 1983 it has reduced casualties by at least 370 deaths and 7000 serious injuries per year for front seat belts and 70 deaths and 1000 serious injuries for rear seat belts (DETR 1997).

Adams concludes that there is no evidence of the seat belt law having reduced overall fatality numbers, and that there is evidence of fatalities having migrated from drivers to vulnerable road users. Although the Government argued at the time that the law had saved lives, it has subsequently attributed almost all the benefit for the small reduction in overall driver fatalities to the introduction of evidential breath testing.[6]

According to the Durbin-Harvey report, commissioned by the Department of Transport following passage of the law, an analysis of fatality figures before and after the law shows:

  • a clear increase in pedestrian, cyclist and rear-passenger fatalities in collisions involving passenger cars
  • no such increase in casualties in collisions involving buses and goods vehicles, which were exempt from the law
  • a reduction in the number of drivers found to be drunk at the scene of collisions
  • a reduction in overall fatalities between the hours of 10pm and 4am (peak hours for drink-driving offences)
  • no reduction in overall fatality rates outside these hours.[15]

Seat belt use is a binary: the belt is either worn or not. Belt laws, which tend to lead to substantial changes in wearing rates over very short periods, would, if the predictions of up to 50% reductions in fatalities are correct, be expected to demonstrate large scale step changes in fatality figures. No such changes have been observed. Whether seat belts reduce fatalities, it is inescapably true that any reductions fall well below the predicted levels, a fact widely interpreted as supporting risk compensation theory.

[edit] Support for seat belt legislation

Lives saved by safety belts and air bags, according to NHTSA, DOT
Enlarge
Lives saved by safety belts and air bags, according to NHTSA, DOT

Other authorities claim that seat belt legislation has reduced the number of casualties in road accidents. For example, this statistical analysis by the NHTSA claimed that seat belts save over 10,000 lives every year in the US. The FARS further writes: [1]

"Research on the effectiveness of child safety seats has found them to reduce fatal injury by 71 percent for infants (less than 1 year old) and by 54 percent for toddlers (1-4 years old) in passenger cars. [...] Among passenger vehicle occupants over 4 years old, safety belts saved an estimated 11,889 lives in 2000."

However, these figures for lives saved are obtained by extrapolating experimentally derived estimates for seat belt effectiveness to the entire population based on recorded seat belt use and recorded crash rates; this is problematic for the reasons noted above and it is argued that this is an example of begging the question: such evidence cannot of itself provide evidence of actual reductions in deaths that might be reasonably attributed to seat belts.

In Victoria, Australia use of seat belts became compulsory in 1970. By 1974 decreases of 37% in deaths and 41% in injuries, including a decrease of 27% in spinal injuries, were observed, compared with extrapolations based on pre-law trends. The Victorian legislation coincided with the oil-crises of the early 1970s, a time when traffic injuries and deaths fell in most industrialised countries. Adams' analysis shows Victoria's injury trends as being above the average for all industrialised countries.

[edit] Current position

[edit] United States

Recently there has been a push for seat belt laws in the United States. As elsewhere, this has resulted in controversy. In addition to the above observations in respect of the measured effect of seat belt laws, the debate in the US has highlighted some other comments which received less attention in other countries.

In USA, seatbelt legislation is left up to state governments. Depending on which state you are in, not wearing a seatbelt is either a primary offense or a secondary offense. Primary offense meaning a police officer can pull you over for the seatbelt law violation alone, and secondary offense meaning you can only be punished for the seatbelt law violation if you're already pulled over for another reason. As of July 2004, 21 states have primary seatbelt laws and 28 have secondary seatbelt laws. The exception being New Hampshire, which does not have a seatbelt law for persons aged 18 and over. [citation needed]

One facet of the US case is speculative consideration of effects on car occupants (e.g., the possibility that seat belt use can cause internal, neck and spinal injuries as it leaves the head free to move inertially while the rest of the body is restrained), and may trap an occupant in a vehicle. However, proponents of seat belts claim that the benefits in injuries saved far outweigh these risks, and do not credit the idea that they prevent occupants from escaping the car (and also claim that in any case being thrown from the vehicle is much more likely to result in death than being restrained within it).

It is valid to consider the issue of rotational injury to the brain, causing diffuse axonal injury, a leading cause of persistent vegetative state, but there is little credible evidence to support the idea that this is positively associated with seat belt use and considerable evidence to support the idea that head injuries are much more likely to happen, and to be severe, in unrestrained drivers.

Many US opponents also object on the grounds that seat belt laws infringe on their civil liberties. This is accorded much higher priority in the US than in some other countries.

In 2004 after being ticketed for not wearing his seatbelt Allan Cronshaw of the state of New York has challenged the state's seatbelt law on the grounds that the law does not allow for a religious exemption. Allan has laid claim to being a reincarnated Ebionite and "James the brother of Jesus" from the Bible. To date the court system will not set a date to hear the case.

[edit] Developing countries

It might be argued that the risk posed to vulnerable road users is of less importance where walking and cycling are relatively insignificant, as they are in the US. In many developing countries, however, pedestrians, cyclists, rickshaw operators and moped users represent the majority of road users. These countries rarely have the resources to physically separate such road users from car traffic (an idea which is itself arguably inequitable, given that those forced into second-class facilities are not the ones posing the danger). In many such countries non-car occupants also represent the majority of road fatalities. Some believe such countries face a serious moral dilemma about importing "Western", "car-centered", models of "road safety" such as compulsory seat belt legislation.

[edit] Dilution of risk compensation effect

There is very little literature considering how risk compensation effects, subjective as they must be, change over time. Although there is good evidence that habitually unbelted drivers will take more risks when belted, and that habitually belted drivers will be more cautious when unbelted, by the nature of laws, new drivers will be habituated from the outset. An interesting footnote to the debate is analysis by Adams of the relationship between accident records and car ownership, a relationship known as Smeed's law ([2]). It appears that this empirical rule relating car casualties to the level of car ownership has continued to hold across several decades of safety interventions, including seat belt laws. It may be that modern drivers, habituated from the outset to seat belt use, are also habituated from the outside to greater expectations of car performance: faster cornering, faster acceleration, later braking. Alternatively it may be that improvements are due to the increasing profile of safety interventions as car ownership increases, whatever the country, as road safety professionals prefer.

[edit] Seat belt legislation around the world

This section gives an overview of the years in which seat belt legislation was first introduced in various countries around the world, this includes both regional and national legislation.

Country Compulsory wearing Compulsory fitting Source
Cars Bus passengers Cars Buses
Driver Front passengers Rear passengers
Australia 1970           [3]
EU 1993       [4]
France 1973 (outside cities), 1975 (cities at night), 1979 (all) 1990 2003 1979   [5]

[6]
Germany 1976 1976 1984 1999 1970, 1979 (back seat) 1999 [7]
Hungary 1976   1993       [8]
India              
Ireland 1979   1992        
Japan         1969   [9]
New Zealand         1979   [10]
Spain              
Sweden 1975 1975 1986   1969 (front) 1970 (rear)   [11]
Switzerland              
United Kingdom 1983 1989 (children), 1991 (all) 2006 (if fitted) 1967 (front), 1987 (rear) 1996 (organised child trips), 2001 (all) RoSPA
United States 1994     2004 [12]

[edit] See also

[edit] External links

Links to sites/studies that endorse seat belts

Links to sites/studies skeptical/critical of seat belt legislation

[edit] References and Further Reading

  • John Adams (1995). Risk. Routledge. ISBN 1-85728-068-7. Authoritative reference on risk compensation theory.
  • Wilde G.S. Target Risk PDE Publications, 1994
  • The Isles report "Seat belt savings: Implications of European Statistics", UK DoT, 1981, Sourced from Death on the Streets, Cars and the Mythology of Road Safety by Robert Davis, Leading Edge Press, North Yorkshire UK, 1992 and "Report questions whether seat belts save lives" by M. Hamer, New Scientist, 7 February 1985 p7
  • Evaluation of Automobile Safety Regulations: The case of Compulsory Seat Belt Legislation in Australia. by J.A.C. Coneybeare, Policy Sciences 12:27-39, 1980
  • Compulsory Seat Belt Use: Further Inferences, by P. Hurst Accident Analysis and Prevention., Vol 11: 27-33, 1979
  • Wilde G.S. Risk Homeostasis and Traffic Accidents Propositions, Deductions and Discussion of Dissension in Recent Reactions, Ergonomics 1988 Vol, 31, 4:439
  • Methodological Issues in Testing the Hypothesis of Risk Compensation by Brian Dulisse, Accident Analysis and Prevention Vol. 25 (5): 285-292, 1997
  • RS 255 The initial impact of seat belt legislation in Ireland by R. Hearne, An Foras Forbatha, Dublin, 1981
  • The efficacy of seat belt legislation: A comparative study of road accident fatality statistics from 18 countries, by J. Adams. Department of Geography University College, London 1981
  • Casualty Reductions, Whose Problem? By F. West-Oram, Traffic Engineering and Control, September 1990
  • The Puzzle of Seat Belts Explained, Press Release of the Annual Conference of the British Psychological Society, April 1999
  • Reconsidering the effects of seat belt Laws and Their Enforcement Status by T.S. Dee Accident Analysis and Prevention., Vol 30(1): 1-10, 1998

[edit] Notes

  1. ^ RoSPA History - How Belting Up Became Law. RoSPA.
  2. ^ John Adams (1982). "The Efficacy of Seat Belt Legislation". The Society of Automotive Engineers.
  3. ^ Wilde, Target Risk
  4. ^ a b Davis, R (1993). Death on the Streets: Cars and the Mythology of Road Safety. Leading Edge Books. ISBN 0-948135-46-8.
  5. ^ Department for Transport, Transport Statistics.
  6. ^ a b John Adams (1995). Risk. Routledge. ISBN 1-85728-068-7.
  7. ^ Evaluation of Automobile Safety Regulations: The case of Compulsory Seat Belt Legislation in Australia. by J.A.C. Coneybeare, Policy Sciences 12:27-39, 1980
  8. ^ Compulsory Seat Belt Use: Further Inferences, by P. Hurst Accident Analysis and Prevention., Vol 11: 27-33, 1979
  9. ^ Source: Department for Transport, Road Accidents Great Britain
  10. ^ 20 facts for the 20th anniversary of front seat belt wearing. Think!. UK Department for Transport.
  11. ^ Durbin J, Harvey A: The effects of seat belt legislation on road casualties in Great Britain, DtP, October 1985
  12. ^ Source:Methodological Issues in Testing the Hypothesis of Risk Compensation by Brian Dulisse, Accident Analysis and Prevention Vol. 25 (5): 285-292, 1997
  13. ^ Lancet, 11 January 1986, p75
  14. ^ SEAT BELTS FACTSHEET - 20th ANNIVERSARY OF COMPULSORY FRONT SEAT BELT WEARING. UK Parliamentary Advisory Council for Transport Safety (2003-01-30).
  15. ^ Durbin-Harvey report, reported in Davis, Death on the Streets: Cars and the mythology of road safety
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