Advancing accessibility : public transport and urban space

Abstract

After decades of academic research, urban accessibility metrics are beginning to see adoption in transportation and metropolitan planning practice. Such metrics capture the potential for reaching destinations enabled by transport (e.g. number of jobs available within a given commute time), not just the mobility benefits accruing from the use of transport (e.g. time and emissions reductions for a given commute), and have well-established advantages. From a transportation equity perspective, for example, measuring the potential for reaching destinations instead of actual travel avoids bias against groups who travel infrequently due to current or historical barriers to access. This dissertation elaborates on how accessibility concepts complement theories of urban planning and social space before considering two related extensions of accessibility metrics for public transport planning. First, drawing on collaborative planning literature, and using mixed-methods including pre-test/post-test survey designs, various versions of interactive mapping tools were tested in public workshop settings. The outcomes of these workshops suggest that accessibility concepts can improve public involvement in transit planning. Suitability for broad public participation applications, however, requires accessibility to be easily customizable and tailored to constraints that users find salient. Constrained accessibility metrics are the second focus of this dissertation. Adjusting accessibility metrics to account for unreliability in actual transit operations, matching and competition in destination opportunities (e.g. jobs), and capacity in transit networks, may help align these metrics more closely with users' personal experience. Spatial analysis techniques are used to implement some of these adjustments and show that they strengthen correlations with broader urban outcomes of interest, such as employment and use of healthcare resources. The concluding part of the dissertation discusses how these findings can inform substantive and procedural dimensions of public transport planning and urban policy.