Public transportation doesn’t always match where and when people actually need it. This mismatch, called a “transit desert,” can lead to unfair access, wasted resources, and even environmental harm. Many tools that cities use to find these deserts rely on broad statistics like population or bus stop locations, but they often miss what really happens on the ground.

In this study, we use a detailed, fine‑grained dataset of real‑world trips from the Salt Lake region to better understand how people actually travel. We show that even downtown areas with lots of buses and riders can be misclassified as underserved when we don’t account for timing, walkability, or land use. Our method helps reveal where the transit system truly fails, and for whom.

These findings can support smarter, more equitable transportation policies. They also point to new ways of using mobility data to guide decisions about land use, emissions, and public investment. This approach can also support assessments of climate resilience or disaster‑response strategies. As cities face climate challenges, changing populations, and growing equity concerns, this kind of behavioral evidence can help better align services with real needs.