When Is the Concept of Generalized Transport Costs Useless? The Effects of the Change in the Value of Time

This paper on transport costs and the value of time is from the proceedings of 14th international Conference on Urban Transport and the Environment in the 21st Century, which was held in Malta in 2008. The authors stress that the value of time cannot be constant; it is affected by travel time, travel fees and other exogenous factors. They use a series of numerical simulations, assuming a nested Constant Elasticity of Substitution (CES) form of the utility function, to show that the change in value of time tends to be sensitive to travel time and slightly sensitive to travel fees. They conclude that the influences of changes in travel time and travel fees on the number of visits can differ greatly even if those changes are equivalent in terms of generalized transportation costs.