Urban transportation analysis of causes leading to the rebirth of light rail in America.

摘要

This dissertation is a review and statistical examination of potential reasons for the fourfold increase in light rail transit usage in the past quarter century. The primary hypothesis of the dissertation is that metropolitan mobility factors are predictors of this increase. The mobility factors studied are urban sprawl, roadway congestion, environmental and equity issues, and metropolitan population. Data from sixty major American metropolitan regions are analyzed to test this hypothesis. In pursuing this objective, the benefits and costs (both direct and indirect) of the dominant modes of urban transportation, namely the automobile and bus and rail transit, are discussed and compared. In addition, the intertwined relationships between transportation modes and the shape of the urban landscape are evaluated with a view toward understanding the potential larger implications of the rebirth in light rail.; Analysis results demonstrate that metropolitan mobility factors---roadway congestion, metro population, and urban sprawl---are statistically significant predictors of rail usage in America's urban areas. The spatial conflict between the compact city and the automobile has indeed sparked a beginning of change in transportation modes and the shape of the urban landscape. Roadway congestion, itself indicative of this spatial conflict, can be predicted based on metro population and population growth rates as well as various measures of urban sprawl. Three measures of sprawl are demonstrated to be critical to congestion and rail usage---centrality, outward migration from the center cities, and urbanized area growth rates. Multivariate regression analyses show that more than 50% of the variance in both roadway congestion and rail usage in metropolitan regions can be explained by the aforementioned mobility factors.; Although spatial conflict has led to an increase in transit usage, metropolitan mobility remains almost exclusively the province of the automobile, and sprawl continues as the dominant form of urban development. It is likely that the home in the country and our own private automobile parked in the driveway will continue to be the American dream. But concerns over roadway congestion, urban sprawl, global warming, and the cost of energy appear to be leading to affordable alternatives that include (1) a multi-modal transportation system making greater use of energy efficient mass transit and (2) mixed use diverse communities where walking or biking to work, school, the corner store, and the nearby transit station are encouraged and made possible by their spatial design.