Urban Spatial Structure, Employment Subcenters, and Freight Travel.

摘要

Metropolitan areas in the U.S. have become increasingly polycentric. Large employment subcenters have emerged outside of central cities, competing against the traditional city center for labor and businesses. The existing literature on land use and transportation focuses on passenger travel, providing little insight into the impact of polycentric metropolitan development patterns on freight activity. Despite a growing literature that suggests the importance of urban spatial structure for passenger travel, the relationship between employment subcenters and freight travel remains largely unexplored. In this study, the authors use the Los Angeles region as a case study to examine the relationship between urban spatial development patterns and freight travel. Using the National Employment Time Series (NETS), they identify employment subcenters in metropolitan Los Angeles. They characterize freight activities associated with subcenters using data from Southern California Association of Governments (SCAG). They develop a regression model that estimates freight activity as a function of geographic characteristics, including whether a location is in an employment subcenter, measures of nearby employment, access to the highway network, and proximity to intermodal freight facilities. The results indicate that employment is an important driver of freight activity; however, employment subcenters have an independent effect on freight activity. The results of this study suggest that further research on urban form and freight activity should assess the effects of employment subcenters and how their particular employment composition and characteristics are associated with freight activities at the metropolitan level. Such an approach would lead to more precise policy recommendations for urban goods movement.