During the bitter, decade-long fight over I-66, opponents of the highway extracted a handful of concessions from federal and Virginia officials, including the promise of a public park over a tunneled section of the highway in Rosslyn.

The final segment of the highway, from the Roosevelt Bridge to the Capital Beltway, opened more than two years ago. But work on an $11 million blockwide park in Arlington has been delayed, the victim of a year-long congressional stalemate over a controversial highway bill.

Congress adjourned last year without approving a highway funding measure, and as a result about $7.5 million in taxes earmarked for interstate highway construction projects remains locked in the federal treasury. It is the first time this has happened since the creation of the interstate highway system in 1956.

Until Congress approves the measure, the money -- including $284.2 million for Maryland and $204.2 million for Virginia -- cannot be released. And few officials connected to the issue are willing to predict when that might happen.

"It's a major problem," said Virginia Highway Commissioner Harold C. King, who said several Virginia projects, such as the I-66 park, have been delayed because of the lack of federal funds. "We've gone ahead as far as we can without federal money."

In Maryland, Baltimore had to use $28 million of its own money to prevent delays on work on the Boston Street reconstruction, Jones Falls Boulevard and the Howard Street transit mall.

"If we don't get a quick solution, Baltimore City will incur some real problems, cash flow problems," said Maryland Secretary of Transportation William K. Hellmann. "They have advance-funded those projects assuming that Congress would act. The longer it takes Congress to act, the longer the City of Baltimore has to carry those funds."

Highway projects valued at $55.6 million in the District are affected by the congressional inaction. The center leg of a freeway that would connect I-395 with New York Avenue is being delayed by the lack of federal money, along with several other projects, including what city officials say is a much-needed Anacostia bridge connecting the Southeast Freeway with the Kenilworth Expressway.

Maryland and Virginia transportation officials say that congressional inaction means higher construction costs because of inflation, and delays in road projects.

To release the federal money, Congress must approve something called the Interstate Cost Estimate, which lists the cost of various projects and shows how the money will be apportioned among states.

But last year efforts by House members to attach more than 20 projects, including a proposed $2.2 billion freeway-tunnel in Boston, encountered strong opposition in the Senate. Senators objected to the cost of the bill, which also became entangled in unrelated constroversies in the Senate.

The Senate Environment and Public Works Committee is scheduled to reconsider the issue Jan. 29, in a bill that does not contain the special projects, an approach supported by the Federal Highway Administration. A House bill will be introduced in a few weeks and will be along the lines of the measure passed by the House last year, according to a spokesman for the House Public Works and Transportation Committee.

Virginia, like Baltimore, used its own money to keep important highway projects on schedule. But transportation officials in both states say they are running low on funds and can no longer advance money to pay for the interstate projects.

"We have advanced projects in Virginia to the tune of over $66 million. We've gone ahead with these without federal money," said King. "We did that last March and April thinking that Congress was about to approve something. We're still waiting, and it's almost March again."

"We just can't afford to" advance more money, said King. "We shouldn't have had to advance the $66 million worth."

Maryland officials are concerned that failure to resolve the controversy quickly could delay the $100 million reconstruction of the Jones Falls Expressway, which is scheduled to start in the fall.

The expressway, a major highway into Baltimore, will require $77.3 million in federal funds, according to Maryland officials. "That could be a real problem," said Hellmann.