Rockville city planners have recommended strict new limits that would reduce by a third the current maximum density allowed in commercial development along heavily congested Rockville Pike, according to a report released yesterday.

The report calls for reducing the size of new buildings by reducing the maximum allowable floor space by one third in commercial developments along the 1.5-mile stretch between Twinbrook Parkway and Viers Mill Road. About 75 percent of that area is zoned for commercial development.

James M. Davis, the city's planning department director, said the proposed change will be presented to the City Council at its meeting on Monday.

The recommendation comes one month after the council decided to extend a seven-month-old building moratorium along Rockville Pike until April 2 to allow meetings with an advisory group made up of business representatives and civic groups.

The moratorium was imposed in June, after city planners predicted that up to 2.6 million square feet of commercial development would be built along the Pike within the next decade. The planners said that such growth would worsen traffic conditions along the six-lane corridor and strain the area's sewer system.

Historically, developers have built one-and-two-story retail shopping centers along the Pike. But in the past two years -- pushed in part by rising land costs sparked by the Metro subway -- mid-rise and high-rise office buildings have sprung up where small outlets once stood.

Council member John Tyner II said in an interview yesterday that he thought that reducing new development by one-third "may not be enough," pointing out that traffic along the Pike has steadily worsened with the increase in retail outlets, which are normally less dense developments than office buildings.

The planning department report also recommends several traffic improvements at key intersections, including the addition of a right-turn lane at the intersection of Rockville Pike and Edmonston Drive, and adding a third northbound lane and a third southbound lane at its intersection with Viers Mill Road.