A geographic perspective on urban commuting

This dissertation examines the spatial organization of urban land use by focusing on the concept of excess commuting. Excess commuting is a metric that gauges how much a city's observed journey to work commuting differs from a theoretical situation where commuting is minimized.; First, excess commuting methodologies are reviewed. A GIS-based simulation conducted on zonal data reveals that excess commuting measurement is influenced by zone size and configuration. Specifically, as fewer areal units are utilized to represent an area, estimates of excess commuting vary significantly, and indeed estimates become more sensitive to the underlying configuration of zones as aggregation increases.; Next, a new measure of excess commuting adapted from the idea of carrying capacity is developed. The new commuting metric incorporates a theoretical maximum commute in order to construct a range of commuting potential. There are several substantive and technical findings produced from analyses of 26 US urban regions: (1) Estimates based on the new method of excess commuting differ from those found using the traditional approach. (2) Observed levels of commuting are related to regional jobs-housing balance as captured by minimum commutes. (3) Maximum commutes indicate the degree of regional jobs/housing polycentricity. (4) Spatial constraints may be placed on the solution procedure in order to limit interaction opportunities, thereby producing more conservative estimates of excess commuting. (5) Both measures of excess commuting may be calculated controlling for commuters' gender/occupation type.; Following this, accessibility as it relates to commuting is explored. Accessibility to goods and services is contingent on urban spatial structure. Spatial interaction model-derived indices of accessibility are developed to point out these differences. Maps generated for 10 urban regions illustrate the decentralized nature of employment accessibility, contrasted with more centralized patterns of residential accessibility.; Finally, a strategic land use model of regional development is proposed. The model is an extension to the excess commuting framework, and is solved using commercial optimization software. Results from Atlanta, GA show that managing employment center growth will be less effective in reducing commuting than addressing residential growth. Analysis suggests that directing growth away from suburbs is most likely to reduce commuting.