A land-use plan that officials hope will begin to transform long-neglected eastern Montgomery County has been sent back to the drawing board because of concerns that it does not accurately forecast the volume of traffic that would be generated by new construction.

Next week, the County Council was scheduled to begin discussions of the White Oak Science Gateway master plan, which proposes to turn 300 acres near the headquarters of the Food and Drug Administration on New Hampshire Avenue into a hub for medical research firms with office space, retail and housing. The blueprint also calls for redeveloping the White Oak Shopping Center and the Hillandale neighborhood, with the entire area served by a new system of bus-only lanes designed to lure people out of their cars and onto mass transit.

Gateway is a joint venture of the county, which owns some of the land, and Percontee, a private developer based in Silver Spring.

The Montgomery Planning Board approved the proposal in September. But when council staff members reviewed it in preparation for next week’s work session, they grew concerned that the board’s traffic analysis may have been conducted with outmoded or incorrect data.

The master plan approved by the planning board, for example, assumed that a “gold standard” rapid-transit bus system would be available along Route 29, the major road that bisects the project area.

In November, however, the council approved a separate long-range transit plan that did not provide for new bus lanes on the segment of Route 29 in Four Corners, near University Boulevard and Colesville Road in Silver Spring. The lanes were omitted in response to protests from residents who did not want Route 29 widened to accommodate the buses.

The disparity means that estimates of new traffic generated by the White Oak project could be incorrect. The land-use plan was returned to the planning board for further analysis.

Officials said that because the council is scheduled to begin work on the county’s annual operating budget next month, it might not be able to consider the White Oak land-use plan until June.

This is the second time that the council has bounced the plan back to the planning board. Last fall, council members returned it because of concerns that proposed road and transportation improvements were inadequate to handle projected traffic.

“It’s very annoying, because we anticipated having all this work done in the fall,” said council member Nancy Floreen (D-At Large), head of the council’s planning committee.