The idea for Yuquan “Wendy” Zhou’s award-winning dissertation came from a personal grocery problem.
Zhou, a Ph.D. student at the USC Price School of Public Policy, lives in a San Gabriel neighborhood that, on paper, has a grocery store nearby – but one she cannot access. That’s because the store, while geographically close to home, is only open while she’s at work.
The grocery shopping situation, while only an inconvenience for Zhou, got her thinking about the outdated ways urban planners determine where to locate public transit and other services. Most measures of accessibility are built on assumptions that people start their trips from home, they are free all day, businesses are always open, and public transportation is always running, she noted.
Zhou, who will soon earn a Ph.D. in Urban Planning & Development, calls these “static maps.”
“Usually, planners use maps based on Census tracts, such as how many grocery stores are within a 1-mile radius of home. But this kind of map can be misleading if it is not considering where these people actually are during the day,” Zhou said. “That’s the motivation for my research, to consider things like store hours and where people are during the day, to see whether people actually have access when a store is open.”
Finding a Realistic Measurement of Accessibility
Zhou’s dissertation introduced a novel, “people-based” approach that measures when and where essential services are reachable in daily life. Using Los Angeles County as a case study, her dissertation proposes a more realistic measure of accessibility by combining millions of anonymized smartphone GPS records, time-varying travel networks, and service locations with operating hours.
Her research found that static maps systematically overestimate real-world access, especially for time-limited services such as food, healthcare, and groceries. The findings, Zhou said, highlight the importance of time-sensitive accessibility measures in planning practice.
“Wendy’s dissertation is the kind of work the field needs”
Geoff Boeing
For example, planners using her measurements may find that a neighborhood that is not a food desert may, in fact, need a grocery store with longer operating hours to accommodate commuters arriving home later.
Zhou’s research recently won the Jack Dyckman Award for best dissertation in planning and development at USC Price School, as well as the Western Regional Science Association’s Charles M. Tiebout Prize for best student-authored paper.
“It’s very validating,” Zhou said of the awards. “Doing a Ph.D. is a hard and challenging process. When you are in the middle of the work for so long, you only see the problems, so it’s really good when your work is appreciated by someone – when people see your work as important and interesting.”
Collaborating with Price Professors
Zhou traces her interest in urban planning to her upbringing in China, where she grew up watching the completion of major infrastructure projects, such as high-speed rail lines, and decided to pursue a bachelor’s degree in urban planning at Sun Yat-sen University in Guangzhou. She even does virtual urban planning for fun, designing homes and villages in the video game Animal Crossing when she isn’t studying real cities.
“I’m excited about planning because it’s literally a plan for the future,” Zhou said. “You plan something 10 years ago and 10 years later it becomes reality.”
After earning a master’s degree in city planning at University of California, Berkeley, she enrolled in the USC Price School to study under Associate Professor Geoff Boeing and learn more about his research using big data to inform planning decisions. The two recently teamed up on a study showing how researchers and planners can predict more realistic driving travel times without access to the expensive proprietary data that many can’t afford.
“The strongest skill I learned here is how to identify a problem and argue with a clear point. Especially in the age of AI, that’s what makes research matter,” Zhou said. “The second thing I’ve really enjoyed is the flexibility and liberty for the Ph.D.s here to collaborate with the professors they want to work with.”
Boeing, who chaired Zhou’s dissertation committee, said her dissertation “tackles a problem hiding in plain sight.” The committee also included Price Professor Marlon Boarnet and Siqin Wang from the USC Spatial Sciences Institute.
“Wendy’s dissertation is the kind of work the field needs: it identifies a longstanding problem, builds a novel solution that handles theory and empirics innovatively, and guides the real world toward better practice,” Boeing said.
