"For most of the 20th century transportation planning goals were almost entirely mobility-based; transportation systems were primarily seen as a means to efficiently, safely, and quickly connect people and freight to desired destinations. However, as the century progressed, cultural, societal and ecological movements had major impacts on how planners perceive transportation networks and public transit more specifically. Several overlapping concerns have altered the role that planners and policy-makers see for transportation and land use planning. Environmental degradation, air pollution, traffic congestion, an unsure energy future, and global climate change, for example, have drastically redefined priorities for planners and policy-makers. These concerns have led to an increasing interest in public transit and active transportation -- walking and cycling -- as potential solutions to many environmental problems. Concurrent to these shifts, concerns of social equity and environmental justice have also entered the transportation planning framework. However, while transportation planning goals have shifted in recent decades to encompass social justice and environmental goals, many of these aims do not have clear indicators or accepted ways of measuring progress. In addition, while these diverse values and ideals do often underlie policy, they can have contradictory influence on transportation planning decisions. Transportation benefits include, what might be termed "tangible" or easily measured outcomes, however, many goals that address issues of social equity have "intangible" outcomes. Not only are the former easier to measure and to present to the public, but they often have more political capital than more socially progressive goals. While a rich body of research has explored these issues, most current planning documents do not make explicit that these conflicts of value exist. The concern from an equity planning standpoint is that very real and important environmental concerns will lead away from the other important roles that transportation systems can play in providing equitable outcomes. In light of these concerns, this dissertation sets out to address four research questions: How do municipalities and transit agencies balance economic, social, and environmental goals and objectives in transportation plans? How do these decisions affect outcomes, particularly with regards to social equity? How can current methods of measuring and understanding active transportation and neighbourhood walkability be improved to better capture these wide ranging objectives? How can these findings be used to improve decision-making in the future? This dissertation highlights the importance of adopting a multi-dimensional and mixed methods approach to examining complex urban issues and processes, and contributes to knowledge in three ways: Identifies a set of indicators that capture elements of social equity in transportation planning and decision-making; Develops methodologies to measure outcomes of transportation infrastructure using accessibility measures that focus on the desired destinations of residents; and Deepens the understanding of how people and households of different socio-economic status "respond" to measures of local and regional accessibility. While most -- if not all -- studies do "control for" socio-economic factors, my work makes these factors the primary focus.In doing so, this research brings awareness of important transportation-related social equity goals and increases the role that these goals may play in decision-making processes." --