Congestion Pricing Reduced Traffic. Now It’s Hitting Revenue Goals.

Ms. Hochul abruptly paused the program in June, just weeks before its scheduled start, over concerns that the toll would impede the city’s recovery. She brought it back shortly after the November elections, with a 40 percent reduction in the tolls, down to $9 from $15 for passenger vehicles. Fees vary for other types of vehicles, including trucks and buses, and steep discounts are offered overnight, when there is less traffic.

If Mr. Trump is successful in ending the toll, projects worth billions of dollars could be mothballed, and the delays would compound the cost to fix the problems in the future, transit experts said. The M.T.A. is seeking $68 billion for its next five-year capital plan, the authority’s largest ever, and funding has been identified for only about half.

Even if the toll continues, a protracted legal fight with the federal government could scare away investors, said Ana Champeny, the vice president for research at the Citizens Budget Commission, a civic watchdog group.

“The market may have a different take on how risky they consider congestion pricing now,” she said, noting that it is highly unusual for the federal government to try to renege on such an agreement.

Kurt Forsgren, the managing director of U.S. public finance at S&P Global Ratings, a major credit ratings agency, said it was too early to tell how the legal dispute would play out. However, further confusion could make it more expensive for the M.T.A. to borrow money for necessary projects, and those costs could be passed onto taxpayers, he added.

“Everyone’s watching to see what will happen,” he said.

Susan C. Beachy contributed research.