Interpretations of Downs–Thomson paradox with median bus lane operations

Document Type

Journal Article

Publication Date


Subject Area

place - asia, place - urban, mode - bus, mode - bus rapid transit, mode - car, infrastructure - bus/tram lane, infrastructure - bus/tram priority, operations - capacity, planning - travel demand management, land use - impacts


Downs–Thomson paradox, Bus rapid transit, Median bus lane, Deterministic user equilibrium, Smartcard data


The Seoul Metropolitan Government has implemented a public transportation priority policy with the introduction of a 121.1 km long of the Median Bus Lane (MBL). Therefore, to analyze the impacts of the introduction of Jongro-gu MBL in January 2018, an effect analysis using the speed and volume of passenger cars and buses in Seoul is conducted in this study. The interpretation of the Downs-Thomson (D-T) paradox demonstrates that the reduction in passenger car mode capacity can increase total social benefits. This study shows that the speeds of passenger cars and buses have reached the deterministic user equilibrium after the MBL introduction, resulting in an increase in total social benefits. Moreover, it demonstrates that the bus priority policies, which gives the right to keep the capacity of buses guaranteed in urban areas, will be effective. The interpretation of the D-T paradox will contribute to the formulation of transport demand management policies.


Permission to publish the abstract has been given by Elsevier, copyright remains with them.


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