What led to the establishment of a rail-oriented city? Determinants of urban rail supply in Tokyo, Japan, 1950-2010

- Determinants of urban rail supply in postwar Tokyo were analyzed.
- The model adopted a lag structure in line with the planning horizon.
- Bayesian model averaging method was used with multivariate time series data.
- Urban rail investment was primarily driven by the increase in urban rail demand.
- This induced supply was critical in establishing Tokyo's transportation system.

This study analyzed the determinants of urban rail supply in Tokyo using time series data for the postwar period. It modeled urban rail supply, measured by vehicle-kilometers of the urban rail service, incorporating demand for urban rail travel, urban rail travel speed, conditions of alternative transportation modes, land use patterns, and socioeconomic conditions as explanatory variables. The model adopted a lag structure for urban rail supply in line with the planning horizon. It was then estimated using the Bayesian model averaging approach, which provided robust estimation results based on our multivariate time series data. The results showed that investments in the urban rail network in Tokyo were primarily driven by the increase in demand for urban rail travel. In effect, demand growth in the Tokyo rail network has clearly translated to supply growth through the planning process; this induced supply has worked as one of the critical components in the establishment of a rail-oriented transportation system in Tokyo. Additionally, the negative effects of bus/tram travel speed on urban rail supply were estimated.