Spatial Heterogeneity And Equilibrium Selection in Urban Mobility

Abstract This paper studies how spatial accessibility shapes long-run equilibrium selection in urban mobility systems. The central mechanism is dynamic: accessibility affects not only individual travel incentives and equilibrium conditions, but also the geometry of the evolutionary state space by shifting basin boundaries and changing which long-run mobility outcomes are attainable from different initial conditions. We develop an evolutionary model in which heterogeneous accessibility is generated by generalized commuting distance and value of time, while congestion is distinguished from aggregate private-car usage. We identify structural accessibility thresholds at which the basin configuration changes qualitatively. Poorer accessibility can generate a basin of attraction of positive measure for persistent commuter car use even under maximum public intervention. Pricing can eliminate the fully inefficient equilibrium, but need not induce convergence to the socially optimal outcome because other dynamically attainable configurations may remain. The analysis therefore identifies a channel that static equilibrium comparisons cannot capture: spatial structure affects urban mobility through basin-based equilibrium selection and path dependence, not only through equilibrium travel costs.