First-Best Downtown Transportation Systems in the Medium Run

This paper investigates first-best downtown transportation systems in the medium run for a broad range of demand densities. A downtown transportation system is assumed to include a subway system that operates on its own network and a congestible street system that accommodates both buses and cars. A “subway†is any mass transit mode that operates on an exclusive right of way; a “bus†is any mass transit mode for which there congestion interaction with cars1. The analysis is “medium run†in the sense that the subway and road networks are fixed, as are their link capacities, and “first-best†in the sense that the planner faces only technological constraints. The analysis is “downtown†only in the sense that it focuses on high levels of demand density that for most metropolitan areas occur only downtown. The analysis is static (stationary state), ignoring the intra-day dynamics of travel and congestion.