Urban Spatial Structure, Employment Sub-Centers, and Passenger and Freight Travel

Project Number


Project Summary

The impact of polycentric metropolitan development patterns on passenger traffic and freight flows is poorly understood.  In major metropolitan areas nationwide, employment sub-centers are transforming from “business only” districts into multi-use locales that often have residential, office, retail, light industrial, and warehousing uses in close proximity competing for space on the same road network.  In this research, we will first identify sub-centers in metropolitan Los Angeles using the National Employment Time Series (NETS), which has the location and industry code of all business establishments in the region. Our initial literature review indicated a much larger gap in understanding freight flows and employment sub-centers – a topic almost absent from the literature – and so we are focusing our research on that question.  Freight vehicle miles traveled will be estimated for sub-centers, possibly based on data from the 2007 Commodity Flow Survey (which reports shipment distances by North American Industry Classification System code) or other methods and disaggregated data on the location of business establishments in the greater Los Angeles region from the NETS.   Initital research indicated that SCAG data on freight flows will be the most useful. This research will allow estimates of both passenger and freight travel associated with different employment centers, providing insights into relationships between land use, industrial structure, and the use of the road and highway system by both passengers and freight. 


Project Status




Topic Area

Integrated Freight and Passenger Systems

P.I. Name & Address

Senior Associate Dean, Academic Affairs; Professor & Director of Graduate Programs in Urban Planning, Sol Price School of Public Policy
University of Southern California
650 Childs Way
Ralph and Goldy Lewis Hall (RGL) 301C
Los Angeles, CA 90089-0626
United States

Funding Source

California Department of Transportation

Total Project Cost


Agency ID or Contract Number


Start and End Dates

8/25/2014 - 5/15/2016


Describe Implementation of Research Outcomes (or why not implemented)

In this study, we 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), we identify employment subcenters in metropolitan Los Angeles.  We characterize freight activities associated with subcenters using data from Southern California Association of Governments (SCAG). We 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 are still preliminary at the time of this report.

Impacts/Benefits of Implementation (actual, not anticipated)

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.  This is a tentative result; the result has not yet been fully completed at the time of this report.