D.C. officials, still smarting from what some saw as short notice from the federal government over the closing of Pennsylvania Avenue in front of the White House, said yesterday that they are worried that no one is certain how the move will affect traffic, area businesses or city finances.

Warily looking ahead to a commute this morning that could clog streets throughout downtown with motorists seeking new ways to get to work, officials said they understood President Clinton's decision to close the avenue between 15th and 17th streets NW to increase security.

But many city officials said yesterday that they learned of the decision only hours before the avenue was closed early Saturday and that they wished they had had more time to discuss with federal officials the consequences of closing one of the District's main thoroughfares for east-west traffic.

D.C. Council members said that it could cost millions of dollars to change traffic lights and street markings and remove revenue-producing parking meters and that they weren't clear whether the federal government would pick up the cost, despite indications that it would. They said businesses east and west of the White House could be harmed, at least initially, by traffic gridlock.

"Clearly, the Secret Service is concerned about the safety of the president and his family," said council member Charlene Drew Jarvis (D-Ward 4). "If they are concerned, I'm concerned. But I am also concerned that the traffic congestion and the rerouting and the removal of parking meters is going to have a negative impact on the businesses in that area."

Del. Eleanor Holmes Norton (D-D.C.), noting the recent bombing of a federal building in Oklahoma City, said, "The fanaticism set loose in the country probably forced the decision to close Pennsylvania Avenue," but "equivalent homework has not been done on keeping downtown open."

D.C. Council Chairman David A. Clarke (D) said the federal government should foot the bill for any costs related to the avenue's closing. "They should pay up," Clarke said. "They should work with the city to design street changes, ground structures, traffic lights. And adverse property rights that affect businesses should be compensated."

Johnny Allem, a spokesman for Mayor Marion Barry, agreed.

"There's a tremendous inconvenience to tourists, commuters and residents, and a considerable price tag involved here to the D.C. government," said Allem, who noted that the costs will include new traffic signs, traffic lights, long-term wear and tear on streets that will carry rerouted traffic and additional police personnel to provide traffic assistance in the next few days.

"It's too early to put a number on all that," he said. "We do expect the federal government to pay. . . . But the inconvenience and the costs are a critical problem for us in the coming few weeks and something we will need to have relief on."

Larry King, director of the D.C. Public Works Department, said federal officials have indicated they would reimburse the city for all expenses associated with the cost of closing the avenue. "That is our understanding and that is what we will be pursuing," King said. "The repercussions of closing Pennsylvania Avenue {are} not in my budget."

Ronald K. Noble, undersecretary for enforcement at the Treasury Department, agreed yesterday that the federal government is committed to paying most or all of such costs, but he said he did not know how much that would be.

The National Capital Planning Commission, the federal government's planning agency for the area, is doing a 90-day study on the closure and will release cost estimates later. The 12-member commission will discuss the plan at its next meeting, on June 1.

"The federal government is committed to making certain the implications of closing Pennsylvania Avenue will be borne by the federal government to a large extent or maybe to a complete extent," Noble said.

Clarke, Jarvis and other council members said they first learned the avenue would be closed through media reports late Friday. Some city officials were insulted by the late warning, which federal authorities said was necessary for security reasons.

Clarke said he first heard about the closing on the Friday evening news, then received a call about 10:15 p.m. from U.S. Treasury Secretary Robert E. Rubin.

King said Secret Service officials called him May 12 and told him the avenue likely would be closed "for safety concerns in the wake of not only the Oklahoma bombing but other things they would not elaborate on."

King and federal officials began developing a plan to close the avenue, King said, that was contingent on Clinton's final decision.

King said he informed City Administrator Michael C. Rogers but, for security reasons, told no one else. He did not know whether Rogers informed the mayor, but Allem said yesterday that "you can say the mayor knew about it the same day Michael Rogers did."

"The whole thing was not to tell a lot of people because {federal officials} did not want anything to happen in the interim before they implemented it," King said.

King said his department's plan for the closing included posting no-parking signs on 15th and 17th streets between Constitution Avenue and K Street and on H and I streets between Pennsylvania and New York avenues. He also came up with a contingency plan for switching the direction of traffic on I Street, which now runs one-way eastbound. D.C. officials also are considering making 15th Street one-way northbound up to K Street.

King said the next time he heard from Secret Service officials was 5 p.m Friday, when they told him the avenue would be closed the next morning.

Clinton directed Rubin to close the avenue after being briefed on an eight-month review of security at the White House conducted by a team of specialists. Closing the street to traffic was one of 11 recommendations from the panel he accepted.

Noble, of the Treasury, said city officials were notified late Friday because Clinton did not decide to close the avenue until that evening. But he said officials at Metro, the Public Works Department and the police department had been put on notice that a decision might be made soon.

"They knew we were thinking about doing something, and they knew a study was going on," Noble said. "At the earliest opportunity, we notified members of Congress, the appropriate council member and the mayor."

Concerns about security at the White House have heightened since the Oklahoma bombing last month. There also have been several recent security breaches at the White House, including a plane that crashed on the South Lawn and a man who fired an assault rifle from the sidewalk north of the mansion.

Suggestions to close Pennsylvania Avenue to traffic in front of the White House have been made several times in the past, motivated by aesthetic or security concerns. During the Kennedy administration, architects working with the president and first lady to preserve buildings along Lafayette Square offered the option of turning the avenue into a pedestrian plaza, complete with fountains and plantings, according to Henry L. Adams, a D.C. and Baltimore architect who worked on the plans with John Carl Warnecke, a District architect.

After the March 1981 assassination attempt on President Ronald Reagan, the idea was revived, Adams said. Warnecke came up with a plan to create a plaza and put a tunnel under it for vehicle traffic, Adams said, adding that he does not know what became of the proposal.

Adams predicts that a traffic tunnel will be "one alternative" the government will discuss again.

About 10 days ago, Adams was called in to speak to Treasury Department officials about their new plan to close the historic avenue. He said Warnecke recently had provided sketches to officials for a plaza based on his old ideas.

"I accept the {security} need" for the closure, said Adams, who added that he thinks a pedestrian plaza "can enhance the environment of the White House." People who want to see the White House will have a better opportunity to see it by walking rather than driving by, he said.

According to Adams and others, the National Park Service has been working for two years on a comprehensive plan for the White House and its surroundings. Recently, it unveiled a plan that included closing the avenue, and the agency has sought comment from architects and urban planners.

Robert A. Peck, former president of the D.C. Preservation League, said he had heard Park Service officials discussing the idea as long as two years ago. "This plan didn't exactly hatch in the last month or two," said Peck, a former member of the Fine Arts Commission, which advises the federal government on design and planning issues.

The closure will have "little if any impact" on the work of the Pennsylvania Avenue Development Corp., whose jurisdiction runs from the Capitol to 15th Street, said Anne Hartzell, the group's director of corporate affairs. The commission was established in 1972 by Congress to change the dilapidated avenue into a premier promenade.