Downtown parking supply, work-trip mode choice and urban spatial structure

- Effects of changes in CBD parking capacity on a closed monocentric city with two transport modes, residential parking and CBD parking congestion.
- Changes in downtown parking capacity can change decisions as where to live and invest and the market supply of residential parking outside the CBD.
- The spatial effects of changes in CBD parking capacity provide insights on the sources of feedback-effects affecting motor-vehicle travel.
- By decomposing pathways by which feedback effects work, this framework is a first step that facilitates more complete parking policy evaluations.

This paper examines the effects of changes in downtown parking supply on urban welfare, modal choice decisions and urban spatial structure using a spatial general equilibrium model of a closed monocentric city with two transport modes, endogenous residential parking and a form of bottleneck congestion at the CBD. Our analysis shows that parking reforms at the CBD that increase delay congestion costs in the short-run such as parking supply limits can be welfare improving if other commuting externalities such as air pollution can be reduced. In addition, because parking limits can also change location decisions such as where to live and invest they may complement anti-sprawl policies efforts by leading to a more compact urban spatial structure in the long run. We also show that changes in downtown parking supply can have different spatial impacts on the market supply of residential parking by affecting urban residents' location decisions. Finally, we investigate whether the self-financing theorem of transportation economics holds within the context of our spatial urban model.