An ad hoc group known as the "Planning for People Committee" has submitted plans to Cambridge City Manager John H. Corcoran for changing the area between Harvard and Brattle Squares into a pedestrian mall.

The Committee includes local businessmen, members of the Cambridge City government, representatives from the Graduate School of Design, the University Planning Office, the Joint Center for Urban Studies, and a number of independent citizens.

Its plans include closing Brattle Street between Boylston and Mt. Auburn and all of Church and Palmer Streets to vehicular traffic. Enlarged sidewalks, sitting areas with benches, and trees would supplant cars in the area. In addition, new off-the-street parking facilities would be encouraged on the perimeter of the Square, and more truck-loading areas would be provided.

'Crazy Conflict'

The group was formed one year ago to alleviate "the crazy conflict between vehicles and pedestrians that goes on every day in the Square," Cornelia B. Wheeler, chairwoman of the group and former Cambridge City Councillor, said yesterday.

"None of the recommendations represent extensive changes or unreasonable expense, but they would make Harvard Square a place where people will want to come at all times," she said.

Corcoran and the City Department of Planning and Development are in the process of reviewing the proposals. In 90 days they will submit an application for Federal funds based on their evaluation of the plan.