A Reassessment of the Characterisation of Congestion on an Urban Road Network — Some Theoretical Suggestions and Illustrative Experiments

  • Truong P. Truong
  • David A. Hensher
Part of the Contributions to Economics book series (CE)

1.6 Conclusions

In this paper we have developed an alternative approach for analysing the phenomenon of congestion within an urban road network. The framework differs from the traditional approach in that it separates out the speed and the density components in the flow variable and uses these to define the ‘price’ and ‘quantitity’ levels of travel demand and supply on a particular link. Having separated out the price and quantity components in demand and supply, we set out a theoretical model to represent the individual demand behaviour for travel activity across a link, based on the concept of a household production function, using a (congested) public infrastructure good (road capacity).

The theoretical approach differs from previous contributions where congestion is usually analysed as an externality rather than in terms of household production using a congested public good. Even though the concept of externality and public goods are closely related, the analysis based on the former concept allows us to see more clearly the role of public infrastructure pricing and investment decisions than mere externality analysis.

The proposed approach lays down the basic foundations for extending the analysis into a more complex road network structure, drawing on economic equilibrium analysis (analogous to the concept of general equilibrium in conventional economic analysis). We have illustrated the applicability and feasibility of the approach for a simple network of two parallel links.


Travel Time Traffic Flow Traffic Density Public Capital Congestion Level 
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  1. Else PK (1981) A reformulation of the theory of optimal congestion taxes. Journal of Transport Economics and Policy 15: 217–232.Google Scholar
  2. Evans AW (1992) Road congestion: The diagrammatic analysis. Journal of Political Economy 100(1): 211–217.CrossRefADSGoogle Scholar
  3. Hensher DA, Greene WH (2003) Mixed logit models: state of practice. Transportation 30(2): 133–176.CrossRefGoogle Scholar
  4. Hills P (1993) Road Congestion Pricing: When is it a good policy? A comment. Journal of Transport Economics and Policy: 91–99.Google Scholar
  5. Hills P (2001) Supply curves for urban road networks: A Comment. Journal of Transport Economics and Policy 35(2): 343–348.Google Scholar
  6. Hills P, Gray P (2000) Characterisation of Congestion on an Urban Road Network Subject to Road-Use Pricing — A Fundamental Review. Paper presented at the IATBR 2000, the 9th International Association For Travel Behaviour Conference at Gold Coast, Queensland, Australia, 2 — 6 July.Google Scholar
  7. Oakland WH (1987) Theory of Public Goods. In: A. J. Auerbach and M. Feldstein (eds) Handbook of Public Economics, Volume 2. North Holland, Amsterdam.Google Scholar
  8. Verhoef ET (1999) Time, speeds, flows and densities in static models of road traffic congestion and congestion pricing. Regional Science and Urban Economics 29: 341–369.CrossRefGoogle Scholar
  9. Verhoef ET, Small KA (2004), Product Differentiation on Roads: Constrained Congestion Pricing with Heterogeneous Users. Journal of Transport Economics and Policy 38(1): 127–156.Google Scholar
  10. Walters AA (1961) The Theory and Measurement of Private and Social Cost of Highway Congestion. Econometrica 29(4) October: 676–99.CrossRefGoogle Scholar

Copyright information

© Physica-Verlag Heidelberg 2007

Authors and Affiliations

  • Truong P. Truong
    • 1
  • David A. Hensher
    • 2
  1. 1.School of EconomicsUniversity of New South WalesAustralia
  2. 2.Institute of Transport and Logistics StudiesUniversity of SydneyAustralia

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