Intermetropolitan Comparison of Transportation Accessibility: Sorting Out Mobility and Proximity in San Francisco and Washington, D.C

Abstract

Both mobility and proximity influence transportation accessibility, but they exist in tension with each other. To understand the region-level trade-off between mobility and proximity requires intermetropolitan comparisons of accessibility. With a focus on the two metropolitan cases of San Francisco and Washington, D.C., we first describe a method for comparing regional accessibility and then explain a method that separates out the effects of mobility and proximity on regional accessibility. We find that the San Francisco region enjoys an accessibility advantage over Washington largely because of faster highway speeds but that central Washington offers an advantage in proximity.