CAR COMMUTERS' MODE CHANGE IN RESPONSE TO TDM MEASURES: EXPERIMENTAL DESIGN APPROACH CONSIDERING TWO-WAY INTERACTIONS

Many studies have shown that individuals’ responses to urban traffic congestion, as
usually assumed by policymakers, are significantly different from their respected actual behavior.
This paper adopts a behavioral approach to examine this difference, using the design of experiment
principles and binary logit models. In this approach, five transportation demand management
(TDM) measures including three push and two pull measures were investigated. Then, effects and
contributions of the measures in diverting car commuters to seven existing non-car modes were
taken into account. This study uses the stated preferences of 288 individuals who regularly use
their private cars to access their job locations in the central Tehran area, to calibrate seven non-car
mode models. The results show that when considering each mode separately, pull measures are
necessary to regulate the market share of each non-car mode. Analysis of the effects of the
measures in considering non-car modes shows that although their contributions are about 14% for
transit accessed by walking and 7% for taxi, they have never contributed more than 5% to other
modes.