出行弹性概念及其应用研究

Conception of Travel Elasticity and Its Applications

摘要:

基于出行链决策中各选择肢的被选概率及其离散程度，给出了出行弹性度的基本概念及数学定义，并提出了三种出行弹性度：出行方式选择弹性度、出发时刻选择弹性度、出行链综合弹性度，给出了以各选择肢被选概率标准差的相关量来确定以上三种出行弹性度的方法。利用广东省中山市的居民出行数据，建立了出行方式选择和出发时刻选择的多项logit模型，标定了上述三种出行弹性度，并进行了弹性度分级。比较了考虑弹性度与不考虑弹性度时交通需求管理措施对交通方式转移量的预测，结果显示不考虑弹性度的转移量预测模型一定程度夸大了交通需求管理措施的实施效果，验证了出行弹性度研究的必要性及其应用价值。

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.