Persistence in urban form: The long-run durability of employment centers in metropolitan areas

This paper documents a marked persistence in the spatial distribution of employment in the Los Angeles Metropolitan Area. Over a medium-term of twenty years -- a period of pronounced growth and change in the region's employment and population -- lagged employment density dominates access variables in explaining levels and ranks of current employment density. Similarly, the probability that a tract is located within a current employment center is largely a function of past membership rather than proximity to highways or the central business district. Moreover, longer-term persistence is also readily apparent: concentrations of employment a century ago explain the current distribution of employment as well as access to the modern highway system. This stability in the location of employment and employment concentrations over medium- and longer-terms suggests important roles for agglomeration, adjustment costs, and the durability of fixed investment in modeling the evolution of metropolitan areas.