要旨：This paper builds on the canonical model of city systems with micro-foundations in terms of input sharing. This model is amended so that the production of local intermediates goes along with emissions in addition to labor. This modification affects the balance between agglomeration economies and crowding costs in favor of the latter. Emissions may have a negative impact on the welfare of consumers locally and globally for the entire city system. National and local governments are assumed to be benevolent and set environmental policies which take the negative effect of emissions on consumers into account. The paper characterizes and compares the social optimum with the allocations under local governments and land developers, allowing for environmental policies to be set either nationally or in decentralized fashion.

要旨：We examine the fine microstructure of commuting in a game-theoretic setting with a continuum of commuters. Commuters' home and work locations can be heterogeneous. A commuter transport network is exogenous. Traffic speed is determined by link capacity and by local congestion at a time and place along a link, where local congestion at a time and place is endogenous. The model can be reinterpreted to apply to congestion on the internet. We find sufficient conditions for existence of equilibrium, that multiple equilibria are ubiquitous, and that the welfare properties of morning and evening commute equilibria differ.

AY2016
program