Author(s)

J. Wang, H. Nguyen & Q. Feng

Abstract

This paper discusses the application of variable demand modelling using SATURN. A practical example, i.e. Merseyside Highway model, is presented to illustrate the effects with and without using elastic assignment. The Merseyside Highway Model has been constructed to support the development and assessment of a wide range of potential public transport, road improvement and land use development proposals in the Merseyside area, UK. The development of the future year highway model includes traffic growth to produce the future year matrices, and also the changes to the road networks to reflect the schemes tested. In order to test the robustness of the Merseyside highway scheme, fixed demand and variable demand assignments via travel cost elasticity have been tested with the results compared and discussed in this paper. The Power function is adopted as it has neutral effect on the trip lengths whilst the Exponential function might result in remarkable trips increase/reduction for shorter trips. It is found that by ignoring the behaviour changes to the journey cost, the highway benefits tend to be over-estimated. It is suggested that using pivot-point estimates of elastic demand, it can bring the robustness to the scheme evaluation. Keywords: elasticity, fixed demand assignment, variable demand assignment. 1 Introduction The Merseyside Highway Model has been constructed to support the development and assessment of a wide range of potential public transport, road improvement and land use development proposals in the Merseyside area. The development of the future year highway model includes traffic growth to

Keywords

elasticity, fixed demand assignment, variable demand assignment