Ever since pandemic lockdowns ground life in American cities to an almost complete standstill more than two years ago, big questions have swirled about the future of urban centers: Will the workers who once populated cities return to offices, bringing vitality back with them? Who wants to live downtown? And can they afford it?

Many of these questions are entwined with the fate of public transit systems, which have long been buffeted by the same broad trends affecting the cities they serve. As my colleagues and I reported this week, that means cities are trying to figure out how to make people feel safe riding subways, commuter trains and buses amid rising crime and violence.

Across the country, transit officials and experts highlighted a fundamental dilemma: Riders feel more vulnerable when fewer people are around. So after ridership plunged because of the pandemic, worries about crime have made it difficult to coax passengers back. Stations and bus stops are emptier, which creates a kind of self-perpetuating cycle.