We Walk Faster, Linger Less, and Miss Each Other More

City streets have become less like town squares and more like conveyor belts. A new study using computer vision and artificial intelligence shows that pedestrians in New York, Boston, and Philadelphia now walk 15 percent faster and linger in public spaces 14 percent less than they did in 1980.

Published this week in the Proceedings of the National Academy of Sciences, the research raises questions about how cities are evolving and what that means for social life, community, and public design.

Four Decades, Four City Spaces, One Big Shift

The research team—led by scholars from MIT, Yale, Michigan State University, Harvard, and the University of Hong Kong—compared archival videos from urbanist William Whyte’s late-1970s fieldwork with matching footage filmed in 2010. The study focused on four iconic spots: Boston’s Downtown Crossing, New York City’s Bryant Park and the steps of the Metropolitan Museum of Art, and Chestnut Street in Philadelphia.

Using AI-powered computer vision models, the team measured patterns in walking speed, social interaction, and how long people stayed in each location. While some behaviors remained steady—like the proportion of people walking alone (67% in 1980 vs. 68% in 2010)—others changed dramatically.

• Walking speed increased by 15%
• Lingering behavior dropped by 50%
• Group encounters became rarer: only 2% of visitors joined a group in 2010, down from 5.5% in 1980

From Public Square to Passageway

“Something has changed over the past 40 years,” said co-author Carlo Ratti, professor of the practice at MIT and director of the Senseable City Lab. “How fast we walk, how people meet in public space—what we’re seeing here is that public spaces are working in somewhat different ways, more as a thoroughfare and less a space of encounter.”

It’s not just the pace. It’s also the purpose. Urban dwellers now tend to organize their meetups by phone and arrive with a destination in mind. Hanging around, watching strangers, or bumping into friends—once hallmarks of city life—are rarer. As Ratti observed, “When you look at the footage from William Whyte, the people in public spaces were looking at each other more.”

Texting, Starbucks, and the Privatization of Public Life

The study floats a few theories for the social retreat from public space. The widespread use of mobile phones means people can coordinate meetups or entertainment in advance, eliminating the spontaneity that once characterized public squares. People may also be avoiding outdoor loitering in favor of air-conditioned comfort.

“Outdoor socializing may have shifted indoors,” the paper notes, citing the proliferation of coffee shops as possible substitutes for sidewalks. Starbucks didn’t exist in 1980. Today, a café on every block offers Wi-Fi, outlets, and climate control—an appealing alternative to a hard bench in the summer heat or winter wind.

New Tools for Urban Design

While the study describes past behavior, its implications are forward-looking. “Public space is such an important element of civic life,” said co-author Arianna Salazar-Miranda, now at Yale. “The more we can keep improving public space, the more we can make our cities suited for convening.”

The AI-powered approach also offers a new tool for understanding how cities evolve. Ratti and his colleagues are now analyzing footage from 40 plazas across Europe to extend their findings.

“The question is: How can we learn at a larger scale?” said MIT’s Fabio Duarte. “This is in part what we’re doing.”

Public Life in the Fast Lane

As sidewalks grow swifter and plazas grow quieter, city planners may need to rethink how to invite people to slow down and connect. Are we designing streets that bring people together—or just get them from point A to point B?

The city may still be alive, but its heartbeat has quickened.

Journal: Proceedings of the National Academy of Sciences
DOI: 10.1073/pnas.2424662122

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