Alleviating metropolitan roadway congestion: The efficacy of alternate urban performance measures at the land use and transportation interface in analysis and policy development.

摘要

With economic and population growth and technological advances, travel congestion has emerged as a universal urban problem. Air pollution and rising per capita energy consumption are among the first consequences, and these in turn compromise our health, economic productivity, and quality of life. Researchers have tried to use many urban measurements such as population density and vehicle miles of travels (VMT) to monitor roadway congestion, and some believe that encouraging compactness would enhance transit usage, and result in VMT reduction, which in turn alleviates traffic congestion. However, the reduction of VMT or trip length cannot directly ease roadway congestion, if the roadways are insufficient and the internal developed area is too dense. Today, they are still unable to completely understand the interaction between land use and transportation, and unable to employ the appropriate approach to link indicator applications with urban development policies. Therefore, the main purpose of this dissertation is to unveil the underlying relationships among land use, transportation, and urban form, and to extract from this means for alleviating work related traffic congestion.; Statistical examination of the congestion variation in 46 metropolitan areas during the AM-peak hours yields these conclusions: population densification coupled with insufficient roadway capacity tends to worsen traffic congestion; higher transit usage probably does not help to relieve congestion effectively, if the transit system could not capture enough commuters; and increasing jobs-housing balance does not necessarily mean less congestion. Indeed, such balance may result from higher roadway congestion, which leads commuters to choose alternative modes for avoiding traffic.; To ease work related traffic congestion, two supply-side strategies—expanding the existing infrastructure and adopting transportation system management—are recommended. Other demand-side strategies include distributing population more uniformly (to urban villages) to encourage non-single-occupant vehicle usage, promoting transit options and jobs-housing balance/imbalance based on the economic characters of an MSA, educating commuters to shift their modal choices, and encouraging the usage of telecommunications for work. Finally, an approach of ensuring enough transit users based on an MSA's employment density is proposed to further facilitate congestion relief.