Leesburg Pike in Tysons Corner is a mishmash of fast-food restaurants, car dealerships and chain stores. Access roads bump up against the main highway, traffic lights are jammed together, and this time of year, cars slow to a crawl.

Now picture an eight-lane, pedestrian-friendly urban boulevard with a Metrorail line overhead.

Managers of the massive project that would extend Metro through Tysons Corner are envisioning just that and will offer specific plans tonight at a public hearing.

But the unveiling of the changes to Leesburg Pike is muted by the fact that they are part of measures taken to reduce the cost of the proposed 11-mile Metrorail extension from $2.4 billion to $1.8 billion. The price still exceeds by $300 million the $1.5 billion in the project's financing plan.

The proposed improvements to Leesburg Pike (also called Route 7) -- which have long been on the drawing board, but have never been specific until now -- are a byproduct of the cost reductions. The cuts were announced in August, but details will not be made public until the hearing tonight.

Planners cut $200 million by reducing by half the length of a planned tunnel near the intersection of Routes 7 and 123 and increasing the amount of aerial track. The second most significant savings would come by using a more common, less architecturally stylized design for columns supporting the elevated portions of the line.

Some Tysons merchants and office-goers already had expressed concern that the columns and elevated tracks would be ugly.

"I want [the line] to look as aesthetically pleasing as possible, and some of that may have to be addressed later on, but right now the important thing is getting rail to service this corridor as soon as we possibly can," said Fairfax County Board of Supervisors Chairman Gerald E. Connolly (D).

When complete, the proposed Silver Line would extend 23 miles from East Falls Church to Dulles International Airport.

Phase one of construction, which could get underway as soon as next December and be completed by 2011, would stretch from the East Falls Church station through Tysons Corner to Wiehle Avenue in Reston.

Officials said yesterday that the proposal now includes a plan to shift the rail line from the south side of Route 7 to the road's median, where it would run on elevated tracks from just west of Route 123 to the Dulles Toll Road.

In doing so, officials said, they would eliminate the access service lanes that now stretch along Leesburg Pike, as well as many left-turn lanes, completely transforming the busy roadway.

"We're trying to create a boulevard effect instead of this strip-mall-oriented, used-car-dealer piece of highway," Connolly said. "I think that over time it's going to be a profound change for the Tysons area and a welcome one."

Officials said the changes would be dramatic for those familiar with the road network.

"You'll have to learn to drive all over again in Tysons," said Marcia McAllister, a spokeswoman for the Virginia Department of Rail and Public Transportation.

Under the current plan, Metrorail would make four stops in Tysons Corner, starting with Tysons East, at the intersection of Route 123 and Scotts Crossing Road. The station would be on the edge of Tysons Corner, where officials said the line would rise 55 feet above the ground. The next stop would be Tysons Central 123, on the north side of Route 123 between Tysons Galleria and Tysons Corner Center.

The proposed route then dips into a 2,100-foot tunnel. Because the tunnel has been shortened, officials said, tracks would now go over the Gosnell Road intersection rather than under it.

From there the route continues on to Tysons Central 7, on Route 7 midway between Gosnell Road and Route 123, and then to a Tysons West stop at the intersection of Route 7 and Springhill Road.

Officials said that the average height of the elevated track -- from the ground to the base of the rail line -- would be 35.7 feet, with the highest point reaching 64 feet where the Beltway crosses 123.

Exactly who would pay the increased cost is unclear. The financing plan for the first phase assumes that the federal government would pay half, with the state and Fairfax County each paying 25 percent. A special tax on Tysons Corner landowners is expected to generate a maximum of $400 million, leaving Fairfax to raise an additional $50 million. The state plans to use money collected on the Dulles Toll Road to pay its share. The project still needs approval and a financial commitment from the federal government.