Conception of Travel Elasticity and Its Applications

Abstract:

This paper defines the elasticity of trip chains as the distribution of the probabilities of different alternatives. Three kinds of travel elasticity are proposed, which are elasticity of mode choice, elasticity of departure time choice, and comprehensive elasticity of mode and departure time. Then methods on how to determine elasticity of trip chains are provided. Based on a dataset of with-in day travel survey in Zhongshan, Guangdong province, two multinomial logit models on mode choice and departure time choice are established to calculate the elasticity of the above three elasticities. Finally comparisons of mode shift prediction considering mode choice elasticity or not under certain travel demand management measures are analyzed. It concludes that mode shift prediction model without considering travel flexibility would exaggerate the effect of TDM, showing that it is necessary to study travel elasticity in transportation management.

Key words:travel elasticity ; travel mode choice;departure time choice; discrete degree of probabilities;multinomial logit model