UC Santa Cruz

This dissertation explores urban form metrics and their environmental outcomes, the impact of motorways on urban sprawl, and transportation accessibility across three interrelated chapters. Chapter 1 begins by examining the relationship between urban form metrics in 462 cities worldwide. By employing the K-Means clustering algorithm and statistical analysis, we uncover distinct typologies of urban form, highlighting the complex relationship between measures such as weighted density, street connectivity, compactness and two environmental outcomes—air pollution and green space access. Findings demonstrate that the emphasis on higher density comes with trade-offs in green space and PM2.5 exposure, while street connectivity is crucial for reducing PM2.5 emissions. Context-specific correlations caution against generalizations, providing a foundation for understanding urban processes and identifying effective policy responses. Chapter 2 examines the impact of motorways on urban sprawl by investigating the correlation between motorway construction period and two key urban form metrics—street connectivity and density—across diverse understudied global contexts. By temporally separating the effects and utilizing a panel fixed effects model, we mitigated concerns related to endogeneity, allowing for a better understanding of the causal impact of motorways. Results highlight the context-dependent nature of the impact of motorway construction and proximity on urban sprawl across various areas. In Chapter 3, we introduce the Individual Experienced Utility-Based Synthesis (INEXUS) accessibility metric, designed to improve upon existing accessibility metrics by accounting for individual preferences and constraints within an agent-based regional transportation model. By differentiating between Potential INEXUS and Realized INEXUS, this metric offers a comprehensive view of transportation accessibility, considering the diverse needs of various subpopulations. We apply this approach to a case study involving alternative ridehail pricing scenarios, demonstrating its effectiveness in evaluating differences in accessibility within and between population groups. These three chapters collectively contribute to a more comprehensive understanding of the complex dynamics at play in urban areas, offering insights for policymakers, urban planners, and researchers. The dissertation underscores the importance of context-specific urban planning and transportation policies, emphasizing the need for sustainability, equity, and adaptability in the face of urban challenges, providing insights for shaping more resilient and inclusive cities.