With councilor Alfred E. Vellucci absent, the Cambridge City Council last night decided to postpone balloting for a new mayor of Cambridge.

Vellucci, whose sister died recently, is viewed as one of the top contenders for the mayoral post, along with councilors Leonard J. Russell and Daniel F. Clinton.

The council also postponed the granting of driveway permits to two of the city's bigger businesses, after liberal members of the council chastised the merchants for ignoring community interests in their plans.

Representatives of Spaulding and Slye, a development firm building a massive office complex at 1000 Mass Ave, agreed to meet with local residents to discuss potential traffic problems. Some councilors said they might vote to deny necessary curb cuts if some agreement could not be reached. "I'm not threatening you; I just want you to sit down and talk," councilor Saundra Graham told a Spaulding and Slye planner.

The council also tabled consideration of a curb cut on Columbia Avenue for Bioran Inc., a medical testing firm that tore down a building on the site in an apparent violation of city law.