Evaluation of Urban Traffic Congestion Externalities Induced by Chiang Mai Public Transit Systems

Abstract

Traffic congestion in urban areas is one of the most pressing problems for urban transport policymakers in the nation.  The urban traffic congestion not only inconveniences the users on roadways, but also affects the entire urban areas. The significances of congestion that have been considered are the increase of travel time, fuel consumption, traffic accidents, and environmental pollution. Public transport has been an alternative transport solution that helps manage the travel demand and reduce traffic congestion in urban areas. This study aims to propose the analytical framework to evaluate congestion externalities induced by road transport under different public transit scenarios being planned in 2017 Chiang Mai Public Transit Master Plan (CMP-MAP). Three public transit systems were compared: conventional transit vehicles (Song-taew), diesel buses, and electric buses. The study applied microscopic traffic simulation and emission models to evaluate the mobility performance, operating speed, air pollution, and energy consumption. The results showed that congestion externalities are affected by public transit modes. The proposed public buses either diesel-based or electric-based would reduce congestion externalities within a certain extent due to the reduction in private vehicles along the corridor. However, its cost-effectiveness and potentials should be further analyzed in detail.