Spillover Effects of Urban Public Transport Vehicles in Tehran Megacity: Global Vector Autoregressive (GVAR) Approach

Urban public transport demand response to various internal and external shocks is one of the most important issues in urban public transport policymaking. The purpose of this study was to investigate the spillover effects of demand for urban public transportation in Tehran megacity using Global Vector Autoregressive (GVAR) Approach during period from 2008 to 2019. The results of the impulse response function analysis indicated that the occurrence of a positive shock in metro demand increases the demand for BRT and decreases the demand for bus. Moreover, a positive shock in bus demand declines the demand for metro as well as BRT simultaneously. The occurrence of a positive shock in BRT demand leads to the increase of metro demand and reduction of demand for common bus. Besides, a positive shock in metro fares decreases the demand for both BRT and common bus while a positive shock in bus fares increases the demand for metro and BRT. When a positive shock occurs in BRT fares the demand for metro increases while the demand for bus and BRT increases gradually. Also, a positive shock in gasoline price leads to the increase of demand for all three types of public transport modes. Moreover, with a positive shock in income per capita, metro demand will remain stable, bus demand will increase while BRT demand will decrease. Finally, the occurrence of a positive shock in the unemployment rate would lead to the increase of demand for metro and BRT and the reduction in demand for bus.