Montgomery County planners say the county will need to spend almost three times more than the $1 billion it has budgeted for roads, rails and new bus lines over the next 20 years to avoid overwhelming traffic congestion.

But several public officials say those estimates are based largely on shopworn ideas that are unlikely to solve the county's most pressing problems.

The planners recommended a set of project priorities yesterday as part of a comprehensive evaluation of Montgomery's transportation demands through 2020. As part of the $2.8 billion plan, county planners called for the construction of a rail line connecting Bethesda and Silver Spring, building the Montrose Parkway and widening a series of intersections that have been on the books for years.

The proposal does not include the construction of a major connector highway to address Montgomery's mounting east-west traffic congestion. Also, according to some public officials, the rail projects proposed in the study do not go far enough toward building a Metro Purple line--a rail route that would follow the contours of the Capital Beltway and link all of Washington's suburbs.

"To say that this is going to be Montgomery's transportation policy over the next 20 years is ludicrous," said County Executive Douglas M. Duncan (D). "After spending $3 billion, we will still have the same problems we have today. That's a waste of money."

The proposals were part of a 108-page study that ranks an array of long-planned transportation projects to help the council best address mounting traffic congestion. The Montgomery Planning Board will debate the proposal this month before forwarding the recommendations to the council and to the county's State House delegation. It will be used to make county funding requests from the state.

"This [$2.8 billion] is what it takes," said William H. Hussmann, the Planning Board chairman. "Even with this level of investment in our infrastructure, the level of congestion rises significantly. This is not even a stand-still proposal."

The plan will likely shape the coming debate over the intercounty connector and Montgomery's broader growth plan, scheduled to be considered this fall. Gov. Parris N. Glendening (D) is expected to announce his plans for the connector soon, while Duncan has endorsed a parkway-style highway to foster economic development statewide. The County Council, however, opposes the project and has the final say over land-use matters.

In the proposal, county planners recommend a new cross-county road network even more modest than the parkway version of the connector. The connector, intended to link Interstates 270 and 95 north of the Capital Beltway, has been held up for five decades, mostly because it would cross environmentally sensitive land.

Instead, county planners are calling for construction of a narrower four-lane road that would join Interstate 370 with Layhill Road, then link with Route 29 along an extension of Norbeck Road. Planners acknowledge the road would carry far less traffic than initially intended for a cross-county highway but say it would have a better chance of being built by avoiding some environmentally sensitive property.

Planners give their highest priority to construction of a rail link between Bethesda and Silver Spring, known as the Georgetown Branch Trolley. The route would join the county's two largest job centers, and perhaps more important, two arms of the Metro Red line. Currently, commuters trying to get from Bethesda to Silver Spring by Metro must travel a long route that goes through Washington before returning to the county.

Duncan campaigned against building the Georgetown branch five years ago and has repeatedly reaffirmed his belief that a more substantial rail line is needed to circle Washington. But a majority of council members have endorsed the project, now in the midst of an environmental review, and may use the planning recommendations to buttress their position.