The controversial Montgomery County bus rapid transit system will be scaled back, after county planners and an outside firm found the original design unnecessary and too expensive.

Larry Cole, a county transportation planner, detailed a more modest system than the original 160-mile design. He said county staff re-examined the BRT routes and found while a larger system would draw riders from throughout the county and reduce driving, economic constraints mean a smaller system is more feasible to construct.

A recent study on the proposed system from the Institute for Transportation and Development Policy, a New York firm commissioned by the county, showed similar findings: The ridership on the rapid buses would not be enough to justify such an expansive system.

Cole announced a 79-mile network with eight routes to be implemented in two phases. There is no estimate of how much the smaller system would cost, but it is half the size of the original proposal, which Cole estimated to cost between $8 billion and $10 billion.

County Executive Ike Leggett said the county is in its initial planning process, and county staff are trying to determine the feasibility. If new studies find the system isn't feasible, it won't be built.

"Just because you don't have the money for it [currently] doesn't mean you don't plan," he said. "If you don't have [the money] and it's not worth doing, and the plans are too expensive, you don't go forward. It doesn't mean you don't plan for it."

Councilman Roger Berliner, D-Bethesda, said anyone who denounces the project before the county is able to determine its feasibility is jumping the gun.

"We haven't figured out the phasing or the financing," he said. "We'll have a debate as to the pace, we'll have a debate as to where, and we'll have a debate as to how, but those debates aren't ripe yet."