Using Spatio-Temporal Constraints to Quantify Transit Accessibility: Case Study of a Potential Transit Oriented Development Location in West Valley, Utah

ABSTRACT Accessibility emerges as the transportation performance measure that emphasizes the benefits of the transportation system users, capturing more than the speed of travel. Transit accessibility shows how easy it is for an individual to travel to a desired destination using public transit. However, in order for transit to be considered as an option in mode choice at all, there has to be a feasible transit route leading from given origin to desirable destination within the available time frame. This paper uses spatial and temporal constraints, and a set of transit features that impact access to transit, to develop a conceptual framework for transit accessibility measurements in the potential Transit Oriented Development (TOD) location in West Valley City, Utah. As this network develops more transit friendly features, both temporal and spatial accessibility indicators will provide useful information on the opportunities the users can reach using transit. The proposed methodology builds upon the traffic and transit data from the case study network, and uses an open source tool to perform transit accessibility measurements by calculating the number of accessible transit stops from each origin. The methodology considers network features, acceptable walking time, available time budget, transit schedule variability and spatial constraints as impact factors in accessibility measurements. The goal of the paper is to establish a feasible set of transit accessibility indicators that would be used for both the case study street network and transit service modifications into a transit friendly and eventually a TOD environment.