What is induced traffic?

We’re sorry, something doesn't seem to be working properly.

Please try refreshing the page. If that doesn't work, please contact support so we can address the problem.

Abstract

Investment in new or up-graded roads both raises the level and alters the pattern of accessibility over the whole area served by the road system. Vehicle-users will perceive the opportunities that this increased accessibility offers and respond in various ways, most of which can lead to more rather than less travel on the system. To the extent that travel increases overall, it can be said to have been induced by the road-improvement. Conversely, congestion as it spreads on the network will deter some travel and can be said to have a “traffic suppression” effect.

The purpose of this first paper is to spell out, as clearly as possible, what is meant by “induced” traffic and to relate its various components to the full range of behavioural responses by travellers. In doing so, it draws upon the recently published (December 1994) report by the Standing Advisory Committee on Trunk Road Assessment (SACTRA) and response by the UK Government. The paper concludes with some of the implications of induced/suppressed traffic for current methods of forecasting and evaluation of road investment, which are covered in more detail by subsequent authors.

This is a preview of subscription content, access via your institution.

References

  1. Department of the Environment/Department of Transport (1994)Planning Policy Guidance. Transport, PPG 13 (March) HMSO.

  2. Department of Transport (1989a) Roads for Prosperity. Cm 693, HMSO.

  3. Department of Transport (1989b) National Road Traffic Forecasts. HMSO, Great Britain

    Google Scholar 

  4. Department of Transport (1990) Trunk Roads, England into the 1990s. HMSO.

  5. Department of Transport (1993) COBA 9 Manual (Revisions up to 15 November), Highways Economics and Traffic Appraisal (HETA) Division.

  6. Department of Transport (1994) Trunk Roads in England, HMSO.

  7. National Audit Office (1988) Department of Transport, Scottish Development Department and Welsh Office, Road Planning. CM688, HMSO.

  8. Royal Commission on Environmental Pollution (1994) HMSO.

  9. SACTRA (1994) Trunk Roads and the Generation of Traffic. HMSO.

  10. Williams HCWL & Moore LAR (1990) The Appraisal of Highway Investments under fixed and variable demand. Journal of Transport Economics and Policy 24: 61–81.

    Google Scholar 

Download references

Author information

Affiliations

Authors

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Hills, P.J. What is induced traffic?. Transportation 23, 5–16 (1996). https://doi.org/10.1007/BF00166216

Download citation

Key words

  • induced traffic
  • suppression