Accessibility and Urban Form

This chapter assesses the relationship between urban form and accessibility by comparing accessibility across metropolitan regions in the United States. A prevalent view among urban planning researchers is that low-density, auto-oriented metropolitan regions are also low-accessibility areas. This view, if supported, would have important implications for policy reform. For metropolitan areas in the U.S. overall, there is a positive relationship between density and auto accessibility. This suggests that land-use policy can be highly relevant to accessibility outcomes. In particular, allowing metropolitan compactness by easing land-use regulations mandating low development densities can improve the effectiveness of the roadway transportation system as defined in accessibility terms. Yet the success of the strategy remains a matter for empirical accessibility evaluation. The relationship between metropolitan density and work accessibility via automobile, while positive, is hardly ironclad, and some low-density regions do offer high auto accessibility. And transportation success overall should not just consider the automobile but should consider accessibility via all travel modes, including walking, cycling, public transport, and cars.