The head of the Metropolitan District Commission has estimated that it will be a year before construction can begin on the Memorial Drive underpasses.

A reliable source said yesterday that MDC Commissioner Robert F. Murphy told Cambridge and university officials that the three underpasses could probably not be built until February, 1965.

Murphy spoke to President Pusey, James R. Killian, Jr., chairman of the M.I.T. corporation, and Edward A. Crane '35, mayor of Cambridge, in a meeting Feb. 6 in Gov. Peabody's office.

According to the source, the commissioner explained that it would take a year to prepare plans, advertise bids, and select a contractor. At the MDC's public hearing and in a telephone interview yesterday, he gave nine to ten months as a rough estimate.

Murphy observed yesterday, however, that it was "hard to say" when the MDC would reach the building stage, and added that it may take longer than ten months.

The figure of a year is regarded as significant because one of the main arguments of Cambridge anti-underpass groups is based on the extension of the Massachusetts Turnpike, which could be finished as early as December. The groups believe--and may now be able to prove--that the turnpike extension will make the underpasses unnecessary by draining traffic from Mem Drive.

Those opposed to the underpasses also hope to mobilize strong public pressure during the year before construction begins. Edward L. Bernays, leader of the Citiens' Emergency Committee to Save Memorial Drive, said yesterday that many people throughout Massachusetts had expressed concern about the underpasses and had volunteered their help in fighting them.

Urged Coordinated Program

Additional details on the meeting in the Governor's office have become available from several sources. President Pusey said yesterday that he and Killian had strongly urged the adoption of a coordinated highway program covering the entire Boston metropolitan area. A delay--"hopefully" of a year--would allow traffic planners to gauge the probable effects of the underpasses, he said.