Urban development with financially sustainable rail service

The positive correlation between urban population density and transit service patronage is well recognized, as was ascertained via statistical approaches in previous studies. In this study, we seek to derive some prescriptive results of the relationship between urban population density and the financial sustainability of rail transit service via analytical approaches. We consider an idealized metropolitan region with a central business district at its center, whose population is distributed according to a certain density saturation gradient pattern. Trips generated from the region to the central business district are served either by the rail service supplemented with feeder buses or by autos. Travelers choose one of the two modes to minimize the travel cost. The traffic congestion effects on highway system for auto users will be considered by assuming flow-dependent travel time delay. The crowding costs of transit services will also be taken into account. The spatial equilibrium travel pattern with modal choices will be modeled by applying a differential equation approach. Then, we study the sensitivity of urban development density on the financial sustainability of the rail service by examining the supply and demand patterns. Through the analysis, the result sheds light on the threshold urban density required, below which the service cannot be sustained financially. The results also provide guidelines for planning urban development with financially sustainable rail services. Copyright (c) 2016 John Wiley & Sons, Ltd.