Title: THE AIR QUALITY IMPACTS OF URBAN HIGHWAY CAPACITY EXPANSION: TRAFFIC GENERATION AND LAND USE CHANGE
Abstract: Since the mid-1970s, traffic congestion on California's urban highways has increased markedly. The roughly 3% annual growth in the ratio of vehicle-miles to lane-miles that occurred during the 1960s accelerated to 4% from 1974 to 1985 and 5% after 1985. Moreover, there was comparatively little upgrading of existing lane-miles over this period. As traffic density increased, so did congestion. By 1988, some estimates put the economic cost of congestion to California at $16 billion in time lost and $1 billion in fuel. Despite a California Division of Highways Plan, developed in 1958, calling for 12 thousand miles of limited access roadways, by 1990 less than 6 thousand had been completed. The curtailment in urban road construction can be attributed to economic, political, and environmental forces. Since road congestion results in increased fuel consumption and vehicle emissions per vehicle-mile, it is possible that the curtailment in highway investment has impaired progress toward improved air quality and energy efficiency. The purpose of this research is to assess the traffic inducing impacts of highway capacity increases in order to better understand the potential benefit of capacity enhancement as a strategy for reducing traffic congestion and improving air quality. The scope of the research is limited to traffic inducement -- the authors did not attempt an overall appraisal of capacity enhancement as a transportation improvement strategy. The research focusses on pure capacity expansions as opposed to the construction of new facilities or significant upgrades (e.g. from a regular road to a controlled access facility) of existing ones.
Publication Year: 1993
Publication Date: 1993-04-01
Language: en
Type: article
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