The San Francisco Bay Area has taken on a distinct polycentric metropolitan form, with three tiers of hierarchical employment centers encircling downtown San Francisco, the region's primary center. In this paper it is found that polycentric development is associated with differentials in suburban and urban commute trip times: commute trips made by employees of suburban centers are shorter in duration than commute trips made by their counterparts in larger and denser urban centers. Differentials were even greater, however, with respect to commuting modal splits. Lower density, outlying employment centers averaged far higher rates of drive-alone automobile commuting and insignificant levels of transit commuting. Smaller, outlying centers were also the least self-contained, with a large number averaging twenty or more times as many external as internal commutes. The effects of housing availability and prices on the residential locational choices of those working both in urban and in suburban employment centers are also investigated in this paper. Locational choices are stratified by occupational class and type of center. High housing prices in and around employment centers were found to displace workers to residences in other subregions, except in the case of professional workers in fast-growing, outlying centers. These workers were attracted to higher-priced nearby housing. In the empirical analysis, significant segmentation in housing choices among workers in fast-growing suburban centers was found. This could be partly due to selective land-use policies implemented by local governments in these areas.
