Advertisement

Smeed’s Law, Seat Belts, and the Emperor’s New Clothes

  • Hugh Laurence Ross

Abstract

Smeed’s Law suggests that as motor vehicle ownership increases, death rates per vehicle decrease. The principal claims of the credit for this decrease are considered: safer vehicles, safer roads and safer road users.

The fact that Smeed’s Law applies both to individual countries over time, and to collections of countries at any given point in time, suggests that safer vehicles cannot be given any credit for the decrease in death rates over time; countries with low levels of vehicle ownership today are achieving death rates per vehicle, with modern imported “safe” vehicles, that are higher than those achieved with primitive vehicles in the early years of this century in Britain and the United States.

The explanation which appears to account best for the available data is Wilde’s risk homeostasis hypothesis: as traffic increases, attitudes toward risk and road user behavior both change in a way that maintains the levels of risk that individuals collectively are prepared to tolerate.

Claims made on behalf of vehicle safety regulations, accident black spot treatment and seat belt legislation are also examined and found wanting.

Seat belts are effective safety devices in accidents. But there is no convincing evidence that legislation compelling their use has reduced the total number of road accident deaths. The Wilde hypothesis suggests an explanation: protecting car occupants from the consequences of bad driving encourages bad driving.

Keywords

Road Safety Seat Belt Road User Road Accident Risk Compensation 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Reference

  1. Abbess, C., Jarrett, D. and Wright, C.C. Accidents at blackspots: estimating the effectiveness of remedial treatment, with special reference to the ‘regression- to-mean’ effect. Traffic Engineering and Control 535–542, 1981.Google Scholar
  2. Adams, J.G.U. The Efficacy of Seat Belt Legislation: a comparative study of road accident fatality statistics from 18 countries, Department of Geography, University College London, January 1981a.Google Scholar
  3. Adams, J.G.U. Transport Planning: Vision and Practice, Routledge and Kegan Paul, 1981b.Google Scholar
  4. Adams, J.G.U. The Efficacy of Seat Belt Legislation. SAE Transactions 2824–2838, 1982.Google Scholar
  5. Adams, J.G.U. Public safety legislation and the risk compensation hypothesis: the example of motorcycle helmet legislation. Environment and Planning C, 193–203, 1983.Google Scholar
  6. American Association for Automotive Medicine, The Human Collision, International Symposium on Occupant Restraint, 1981.Google Scholar
  7. American Seat Belt Council, evidence to the U.S. House of Representatives Committee on Public Works and Transportation on Safety Belt Usage, June 1978a, p. 235.Google Scholar
  8. American Seat Belt Council, Seat belt Use Abroad, 1730 Pennsylvania Avenue N.W., Washington, D.C., 1978.Google Scholar
  9. American Seat Belt Council, International Seat Belt and Child Restraint Use Laws, 1980.Google Scholar
  10. Australian House of Representatives Standing Committee on Road Safety, Report on Passenger Motor Vehicle Safety, May 1976, Parliamentary Paper no. 156/1976.Google Scholar
  11. Conybeare J.A.C. Evaluation of automobile safety regulations: the case of compulsory seat belt legislation in Australia. Policy Sciences, 27–39, 1980.Google Scholar
  12. DTp (Department of Transport Great Britain), Road Accidents and Casualties in Great Britain—Third Quarter 1983. Statistical Bulletin STC4(84)1.Google Scholar
  13. Duff, J.T. The effect of small road improvements on accidents. Traffic Engineering and Control 244–245, 1971.Google Scholar
  14. Evans, L. Accident involvement rate and car size. Accid. Anal, and Prev, 76, No. 5 /6, 387–405, 1984.CrossRefGoogle Scholar
  15. Evans, L. Accident involvement rate and car size. Accid. Anal, and Prev, 76, No. 5 /6, 387–405, 1984.CrossRefGoogle Scholar
  16. Grime G. The protection afforded by seat belts, Transport and Road Research Laboratory, Crowthorne, Berks, SR449, 1979.Google Scholar
  17. Hauer, E. Selection for treatment as a source of bias in before-and-after studies. Traffic Engineering and Control, 419–421, 1980.Google Scholar
  18. Hearne, R. The Initial Impact of the Safety-belt Legislation in Ireland. An For as Forbartha RS255, 1981.Google Scholar
  19. Huddart, K.W. Accident migration—true or false?, Traffic Engineering and Control 267, May 1984.Google Scholar
  20. Hurst, P.M. Compulsory seat belt use: further inferences. Accident Analysis and Prevention, 27–33, 1979.Google Scholar
  21. IIHS (Insurance Institute for Highway Safety) Safety Belt Use: A Fact Sheet, December 8, 1977.Google Scholar
  22. IRF (International Road Federation), World Road Statistics, Table IV, published annually.Google Scholar
  23. Jacobs, G.D. and Sayer, I.A. Road accidents in developing countries. Transport and Road Research Laboratory, England, SR807, 1983.Google Scholar
  24. Jacobs, G.D. and Sayer, I.A. work in progress at Transport and Road Research Laboratory, 1984.Google Scholar
  25. Jonah, B.A. and Lawson, J.J. The Effectiveness of the Canadian Mandatory Seat Belt Use Laws. Accident Analysis and Prevention. In press 1984.Google Scholar
  26. Jadaan, K.S. and Salter, R.J. Traffic accidents in Kuwait, Traffic Engineering and Control, 221–223, 1982.Google Scholar
  27. Lowrance, W.W. The nature of risk. Societal Risk Assessment (R.C. Schwing and W.A. Albers eds.) Plenum Press, 1980.Google Scholar
  28. Lund, H.W. Komentarer til, H.W. Komentarer til “The Efficacy of seat belt legislation,” The Danish Council of Road Safety Research, May 1981.Google Scholar
  29. Lund, H.W. Danish Council of Road Safety Research, personal communication, 1982.Google Scholar
  30. Mackay, M. Letter to The Times, June 11, 1981a.Google Scholar
  31. Mackay, M. quoted in “Belt Report Slammed”, Motor, March 7, 1981b.Google Scholar
  32. Mackay, M. quoted by M. Hamer in New Scientist Feb. 19, 1981c.Google Scholar
  33. Mackay, M. Reducing car crash injuries: folklore, science and promise. Foley Memorial Lecture, published by Pedestrians Association, 1 Wandsworth Road, London SW 8, 1982a.Google Scholar
  34. Mackay, M. Seat belts under a voluntary regime. Proc. IRCOBI, Koln, Germany, published by ONSER, Lyon, France. Sept. 1982(b).Google Scholar
  35. McKenna, F.P. The human factors in driving accidents: An overview of approaches and problems, Ergonomics, vol. 25, 10, 867–877, 1982.PubMedCrossRefGoogle Scholar
  36. McKenna, F.P. Do safety measures work?—Comments on Risk Homeostasis Theory, MCR Applied Psychology Unit, 15 Chaucer Road, Cambridge, 1984.Google Scholar
  37. NTS—National Travel Survey, Department of Transport, HMSO, 1983.Google Scholar
  38. Ontario Ministry of Transportation and Communications, Motor Vehicle Accident Facts, published annually.Google Scholar
  39. Orr, L.D. The effectiveness of automobile safety regulation: evidence from the FARS data, American Journal of Public Health, in press.Google Scholar
  40. Peltzman, S. The effects of automobile safety regulation. Journal of Political Economy, vol. 83, no. 4, 677–725, 1975a.CrossRefGoogle Scholar
  41. Peltzman, S. Regulation of Automobile Safety. Evaluative Studies 26, American Enterprise Institute for Public Policy Research, Washington D.C., 1975b.Google Scholar
  42. RAGB—Road Accidents Great Britain, HMSO, published annually.Google Scholar
  43. Riley, D. Drivers beliefs about alcohol and the law, Research Bulletin, Home Office Research and Planning Unit, HMSO, 1984.Google Scholar
  44. Robertson, L.S. A critical analysis of Peltzman’s “The Effects of Automobile Safety Regulation.” Journal of Economic Issues, vol. XI, no. 3, 587–600, 1977.Google Scholar
  45. Robertson, L.S. Automobile safety regulations and death reductions in the United States. American Journal of Public Health, 818–822, 1981.Google Scholar
  46. Robertson, L.S. Injuries, an Insurance Institute for Highway Safety Book, Lex-ington Books, 1983.Google Scholar
  47. Ross, H.L. The Scandinavian Myth: the effectiveness of drinking-and-driving legislation in Sweden and Norway, Evaluation studies—Review Annual, vol. 1, Sage, 1976.Google Scholar
  48. Rumar, K., Berggrund, U., Jernberg, P. and Ytterbom, U. Driver reaction to a technical safety measure—studded tires. Human Factors, 443–454, 1976.Google Scholar
  49. Sayer, I.A. work in progress for the Transport and Road Research laboratory, Crowthorne, Berkshire, England, 1984, personal communication.Google Scholar
  50. Sayer, I.A. and Hitchcock, R. An analysis of police and medical road accident data: Sri Lanka 1977–81, Transport and Road Research Laboratory, England, in press.Google Scholar
  51. Smeed, R.J. Some statistical aspects of road safety research. Journal of the Royal Statistical Society, Series A, Part I, 1–34, 1949.Google Scholar
  52. Smeed, R.J. Variations in the pattern of accident rates in different countries and their causes. Traffic Engineering and Control, 364–371, 1968.Google Scholar
  53. Smeed, R.J. and Jeffcoate, G.O. Effects of changes in motorisation in various countries on the number of road fatalities. Traffic Engineering and Control, 150–151, 1970.Google Scholar
  54. Smeed, R.J. The usefulness of formulae in traffic engineering and road safety. Accident Analysis and Prevention, 303–312, 1972.Google Scholar
  55. Smith, J.Q. Search effort and the detection of faults, British Journal of Mathematical and Statistical Psychology, 181–193, 1981.Google Scholar
  56. Society of Automotive Engineers, Advances in Belt Restraint Systems: design, performance and usage, P–141, 1984.Google Scholar
  57. Statistics Sweden, Road Traffic Accidents with Personal Injury, published an–nually.Google Scholar
  58. The National Institute for Physical Planning and Construction. Research, Road Accident Facts 1982: Ireland. Dublin, 1983.Google Scholar
  59. Tingvall, C., Is Adams right?—Some aspects of a theory concerning effects of seat belt legislation, Journal of Traffic Medicine, 41–47, 1982.Google Scholar
  60. TSGB—Transport Statistics Great Britain, HMSO, published annually.Google Scholar
  61. Trinca, G.W. Thirteen years of seat belt usage—how great the benefits, Advances in Belt Restraint Systems: design, performance and usage, SAE P–141, 15–28, 1984.Google Scholar
  62. U.S. Department of Transportation, Federal Motor Vehicle Safety Standards— Occupant Crash Protection, NHTSA, 49CFR 571 (Docket no. 74–14; Notice 30) 1983.Google Scholar
  63. Wilde, G.J.S. The risk compensation theory of accident causation and its practical consequences for accident prevention, paper presented at the annual meeting of the Osterreichische gesellschaft fur Unfallchirurgie, Salzburg, 1976.Google Scholar
  64. Wilde, G.J.S. The theory of risk homeostasis: implications for safety and health, Risk Analysis, 209–225(a) and 249–258 (b), 1982.Google Scholar
  65. Wilde, G.J.S. and Kunkel, E. Die begriffliche und empirische problematik der riskocompensation!,Zeitschrift fur Verkehrssicherheit, 30, 2, 1984.Google Scholar
  66. Wright, C.C. and Boyle, A.J. Accident ‘migration’ after remedial treatment at accident blackspots, Traffic Engineering and Control, 260–266, May 1984.Google Scholar
  67. Yankauer, A. Deregulation and the right to life (editorial). American Journal of Public Health, 797–798, 1981.Google Scholar
  68. Foldvary, L.A. and Lane, J. C., The effectiveness of compulsory wearing of seat belts in casualty reduction. Accident Analysis and Prevention, vol. 6, no. 1, September 1974, pp. 59–81.CrossRefGoogle Scholar
  69. Hudson, Sir William. Compulsory wearing of seat belts. Health in N.S.W., 11, 3, 12–15, 1970.Google Scholar

Copyright information

© Plenum Press, New York 1985

Authors and Affiliations

  • Hugh Laurence Ross
    • 1
  1. 1.University of New MexicoAlbuquerqueUSA

Personalised recommendations