Demand forecast of public transportation considering positive and negative mass effects

Document Type

Journal Article

Publication Date


Subject Area

place - asia, place - urban, ridership - behaviour, ridership - commuting, ridership - demand, ridership - forecasting, planning - travel demand management


Public transportation, Social interaction, Mass effects, Equilibrium


Demand forecast of new public transportation (PT) is essential for appropriate policymaking. In the forecasting process, the effects of social interactions on individual choices are attracting considerable attention. Traditionally, these interactions have been evaluated in the relationship between the individual’s behavior and the group’s behavior. Conformity has thus become a central issue in this interaction for its mass effect. In the case of PT usage, an individual will have a higher propensity for PT usage when more people in his/her preference group use it. This study shows the need to add an issue, in-vehicle congestion, to the interaction analysis. When more people use PT, occupancy increases and the vehicles become congested, making PT a less attractive option. Both the positive mass effect of conformity and the negative mass effect of in-vehicle congestion on individual choices of PT usage were addressed using an equilibrium calculation based on the estimated utility function of PT usage. For the new PT system to be constructed in Ho Chi Minh City, usage proportions for student, company employee, and government employee groups were estimated of 19.6%, 10.4%, and 10.2%, respectively. A congestion ratio of 61% was found to be the social equilibrium of PT usage and of travel demand for commuting trips by PT. These findings provide an improved, practical picture of the future usage of the new PT system, which is beneficial to effective policymaking and planning.


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


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