With the countdown clock in City Hall today showing 792 days until the arrival of a new mayor, the Bloomberg administration is facing the tall task of implementing its ambitious, mostly market-driven development plans at the very time that the local economy appears headed toward a slowdown.

At the center of the city’s efforts is a Michigan-raised former investment banker, Deputy Mayor Daniel Doctoroff, the man who led New York’s failed bid for the Olympics and catalyzed a far-reaching set of economic development initiatives in the process.

As city and state revenues tighten — Governor Spitzer’s budget office yesterday projected a state budget gap of $4.3 billion for the next year, just as the city announced a hiring freeze and impending budget cuts — the bulk of those initiatives face a critical juncture as the Bloomberg administration’s time winds down.

Successful development of the Far West Side, for instance, depends in large part upon the confidence of investors in the unproven business district. The funding of the no. 7 line extension, in turn, depends on tax revenues from the area, a market-related funding mechanism characteristic of the Bloomberg administration.

Thus Mr. Doctoroff, who talks with a confident, measured tone, is pledging to push through his initiatives to a point of inevitability, so that any successor administration would be unwise to do anything but see them to their full completion.

“We are definitely now very focused on ensuring that the plans that we’ve made are irrevocable,” Mr. Doctoroff said in an interview. “It is time to ensure that we execute on what we’ve put in motion.”

While Mr. Doctoroff has directed numerous large-scale rezonings, sustainability initiatives, and other policies, thus far the most defining features of his legacy-to-be have not taken any physical form, a fact most noticeable on the West Side.

The desired expansion to the Jacob K. Javits Convention Center is facing a major retooling by the state amid cost overruns, and a developer for the land over the West Side rail yards will not be selected for months. Further, the plan to remake Pennsylvania Station will require hundreds of millions in public dollars, and the city and the state have yet to settle on who will cover any added costs on the West Side extension of the no. 7 subway line, though the bulk of the funding was approved last week.

For those projects over which he exerts much control, Mr. Doctoroff is pushing for ambitious timelines: He said he wants to see a groundbreaking for the no. 7 extension and a developer selected on the West Side rail yards before the close of the year.

Many of his efforts depend in large part on leveraging the strength of the real estate market to see progress, including the city’s goal of producing 92,000 units of “affordable” housing by 2013 and creating waterfront parkland along the shores of Brooklyn.

Such reliance on private investment adds a level of vulnerability to the city’s goals, real estate and policy experts say, especially in the event of short-term economic slowdown.

“If the economy slows down significantly, they’re going to have a hard time implementing it,” the chairman of the urban affairs and planning department at Hunter College, Stanley Moses, said of the city’s development strategy.

A potential stumbling block could be found in the state government, as significant new funding will likely be needed for the redevelopment of Pennsylvania Station, the development of Governors Island, and possibly for the Javits Center — something of a large task given declining tax revenues and a governor who has pledged parsimony.

“The problem here is that the projects are not worth the amount of money that it’s now clear they’ll need,” Assemblyman Richard Brodsky, the chairman of the committee that oversees the state’s development agency, said.

“There’s a stubborn unwillingness to deal with reality here,” Mr. Brodsky, a frequent critic of the Bloomberg administration, said, condemning the “mediocre” nature of the state and city’s concept for the Javits expansion.

With much of the West Side development targeted for the area just east of the Javits Center, uncertainty with both the venue’s expansion and the local economy could take a toll, many say.

“The investment firms that are looking to a relocation of the West Side, and others, may postpone decisions, which means that there can be a slow up in economic development activity,” the CEO of the Partnership for New York City, Kathryn Wylde, said.

Still, Mr. Doctoroff expressed a strong optimism that the initiatives can weather a turn in the market, and that the city will be able to raise the cash necessary to properly fund the initiative for the Bloomberg administration’s expansive development legacy. Such cyclical shifts are common to the city, he said, and a long-term view is necessary.

“For anything we want to do, we will come up with money,” he said. “That’s no different from the way it was five years ago when we started.”