In a country where the car is still king, New York had stirred hope that an ambitious policy prioritizing mass transit was possible.

But that optimism unraveled this month, when Gov. Kathy Hochul abruptly halted a congestion pricing tolling program that promised to take thousands of cars a day off the streets of Midtown and Lower Manhattan while generating billions for critical repairs and improvements to the subways, buses and two commuter railroads.

The governor’s decision came amid a fierce outcry from opponents, including many drivers from the boroughs and suburbs outside Manhattan. In doing so, she punched a $15 billion hole in the capital budget of the Metropolitan Transportation Authority, leaving long-planned work on the subway in limbo.

The last-minute decision to call off congestion pricing, which was decades in the making, has turned what was supposed to be a major win for mass transit into a cautionary tale. It has also renewed conversations among city and transportation leaders and experts about the future of transit systems around the country and how to pay for them.

“I’m trying to hold out a little bit of faith,” said Jarred Johnson, the executive director for TransitMatters, an advocacy group in Boston, where the Massachusetts Bay Transportation Authority’s budget deficit is expected to surpass $800 million over the next five years. “Certainly, New York City will be a huge setback.”