Public transit access to healthcare facilities is a growing problem for the elderly population in both urban and rural settings and contributes to delayed health seeking behaviors, missed appointments and poorer outcomes. The entire travel chain presents challenges including the transportation modes and the transfer points that together make up the route linking home to healthcare facilities. While the barriers faced by elders are well known to healthcare providers, they are rarely incorporated into studies of actual travel behavior and needed infrastructure improvements. Research from the transportation community defines a travel chain into an aggregate, easy-to-quantify metric, including transfer wait time and number of transfers; research in the public health literature models access to care and missed appointments as a function of travel, yet characterizes transportation solely on the basis of the supply of transportation modes. Implicitly both fields uphold speed of transport as the ultimate feature of mobility, rather than accessibility. However, for public transit to be a viable option for the elderly, the entire travel chain must be accessible. This project seeks to link transportation systems engineering and public health with the goal of understanding the physical infrastructure constraints and the mobility constraints of elderly travelers as they traverse the transportation network, and how these two components come together to shape the access to healthcare facilities for elders. This research has the potential to enhance our understanding and ability to model how elders make travel decisions based on the accessibility of their entire travel chain, particularly the first and last mile connections. The PI will convene an Elder Mobility Advisory Committee with experts across campus, gathered from the PI’s relationships across campus, that will guide this research and assist the PI in developing a research plan regarding critical needs facing elders when they consider traversing the travel chain to access a healthcare facility and identifying target populations, sampling methods, and approaches for data collection. The objective of the proposed work is to establish a detailed understanding of elder mobility to enable a large-scale study involving modeling healthcare access through the lens of transportation and travel chain barriers for the elderly. The research will fundamentally change our understanding of 1) how elders make travel decisions based on the accessibility of their entire travel chain, particularly the first and last mile connections and 2) how the travel chain should be planned to ensure accessibility for all populations.