The San Francisco Planning Commission on Thursday approved a 40-story, 304-unit tower and public plaza on the northwest corner of Market Street and Van Ness Avenue, a development that will transform one of the city’s busiest intersections.

While members of the Hayes Valley Neighborhood Association objected to the amount of parking the developer proposed — .45 of a space per unit rather than the .25 per unit the neighborhood plan calls for — commissioners said that the project’s overall benefits far outweighed the negative environmental impacts of having more cars in the tower.

“I love this project. I love the way it looks,” Commissioner Myrna Malgar said. “I can envision what it will do to that corner, and I want it to be built.”

The Hayes Valley neighborhood group had pushed the developer, Build Inc., to trim the number of parking spaces by 60 spots, from 136 to 76, in keeping with the 1-for-4 parking ratio in the 2007 Market and Octavia Neighborhood Plan. But the developer argued that the higher parking ratio is needed to attract enough financing to make the $400 million project a reality.

“We have lowered (the parking ratio) as much as we can,” said Build Inc. partner Michael Yarne. “This is a hard issue. We have certain financing realities.”

The vote was 6-0 on certifying the environmental report, and 5-1 on the conditional use that allows for the extra parking. Commissioner Joel Koppel voted against allowing the additional parking, saying he was “overwhelmed by the testimony” of neighborhood groups that didn’t want the extra parking spots.

Build Inc. worked on the plan for 30 months and held 88 community meetings. In addition to the 304 condos, Build will fund 94 units of off-site affordable housing, most of which will be built on three parcels on Octavia Boulevard. The maintenance of the 16,000-square-foot plaza, which will have significant arts programming, will be paid for by the condo owners.

Upper Haight resident Catherine Roberts said that even the .25 parking ratio is too high for a public transit hub like Van Ness and Market.

But the developer argued that the .45 parking ratio is extremely low for a high-rise condo. The average high-rise condo project in San Francisco has had a parking ratio of 1.04 spaces per unit, according to Alan Mark of the Mark Co., which markets condominiums.

Several commissioners predicted that someday high-rise condo projects in San Francisco could be built without parking — but that is not the case today.