Though the report acknowledged that the authority has managed to rescue the subway from past crises, it contends that the authority is no longer up to the job. “The M.T.A., as currently funded and structured, cannot keep up,” the report said. “Unless we can find new ways to deliver improvements and modernization, the subway system will continue to slip further behind.”

In response to the report, Joseph J. Lhota, the transportation authority’s chairman, said in a statement: “While we don’t need to create a new bureaucratic structure, we agree that securing a dedicated revenue source — preferably one that also battles congestion — is essential.”

Mr. Rechler said a more efficient and focused organization was vital to lead the subway overhaul. While details would be worked out later, he said that the new subway corporation could operate with more flexibility than traditional government agencies, which are often bound by outdated rules and regulations.

“We’re asking the public for a multibillion-dollar commitment to get this done,” Mr. Rechler said. “I think it’s critical that it goes into an organization that is designed to solely execute on this mission.”

The report did not provide any cost estimates for creating a subway corporation, but noted that there would be “upfront legal and administrative costs” in addition to capital expenses for the subways. It said that dedicated revenue sources would be necessary to support the subway corporation, such as taxes, fees or congestion pricing. Gov. Andrew M. Cuomo is expected to announce a congestion pricing plan early next year for the city.

The report’s to-do list for the subways includes building new subway lines to underserved areas and reducing crowding at stations by creating larger entrances, enlarging corridors and mezzanines, and moving nonessential structures such as newsstands from platforms. It also advocates increasing access for riders with disabilities and making subway stations more bearable through better ventilation and more natural light. Though the authority has already started to make some improvements, such as updating signals, the report said the pace is so slow it could take decades to finish.

The report calls for closing the 24-hour subway system in the early morning hours during the week for routine maintenance and increasing bus service as an alternative. An average of 85,000 riders are on the subways between 12:30 a.m. and 5 a.m., or just 1.5 percent of the total daily ridership, according to the report.