Seeking a truce with critics of its contentious expansion proposal, Castilleja School this week submitted a revised plan to the city of Palo Alto that reduces the size of a proposed garage and retains two homes that had been previously slated for demolition.

The revised application, submitted on Monday, shrinks the footprint of the garage by about 22%, from about 45,000 square feet to about 35,000 square feet. The smaller size means that the underground garage would no longer encroach into the below-grade setback along Embarcadero Road, obviating the need for a variance from the city. It also means that the Old Palo Alto neighborhood school will no longer need to demolish two residences at Emerson Street, including the Lockey house at 1263 Emerson St., which was built in 1912.

With the new plan, the private school at 1310 Bryant St. is trying to address some of the key issues that opponents to the expansion have raised over the past two years, as the project advanced through the city's planning process. While some neighbors have lauded Castilleja's plan to modernize its facilities, others have suggested that the proposed changes — most notably, the new underground garage — would exacerbate traffic congestion around the campus.

Castilleja's smaller garage would have space for 96 vehicles; the prior proposal, submitted last July, had 115 spaces in the garage.

Overall, Castilleja's plan calls for demolishing several existing buildings, including the Fine Art Center and the Campus Center, and constructing a modern, nearly blocklong building along Kellogg Avenue. Altogether, Castilleja would demolish about 84,572 square feet of floor area, and construct 84,124 square feet, according to project plans.

Lorraine Brown, Castilleja's director of communications, said the school has already made numerous compromises with neighbors as it refined its modernization plan. By revising the garage design, she asserted, the school is demonstrating that it is listening to neighbors' concerns and altering the project accordingly.

Brown said she believes this change "can have a most significant impact toward leading us toward a shared solution." It responds to residents concerns about traffic problems and about the need to preserve homes and trees. While the plan shows that the project would still require 22 trees to be removed, that is nine fewer than under the prior plan, according to the school.

And now that the homes at 1235 and 1263 Emerson St. won't be demolished, Castilleja plans to use them to house school employees.

"What we really hope is this plan takes a step in moving Palo Alto toward having a Castilleja that meets the needs of future generations of young women and also meeting the needs of our immediate neighbors," Brown said.

The revisions are unlikely, however, to quash all of the neighborhood concerns, which range from complaints about Castilleja's enrollment figures to the number of events the school holds — and the surge in traffic that comes with them. Some neighbors have called for Castilleja to build a second campus elsewhere, while others have opposed the school's plans to increase its enrollment from the current level of 430 students to about 540, as the school hopes to do.

Some of the mistrust dates back to 2013, when Castilleja was fined $265,000 by the city for vastly exceeding the 415-student limit in its permit. Since then, the school had been required to reduce its enrollment by about five students per year.

At a news briefing Tuesday afternoon, Nanci Kauffman, head of school at Castilleja, said the school has done everything that the city has requested.

"We are in compliance with what the city has been asking us to do," Kauffman said. "When we came forward about over-enrollment, the city put together a plan to come into compliance and we've been following that."

That argument has not swayed some of the school's neighbors. The blocks around Castilleja continue to display competing yard signs, some voicing support for the expansion and others stating their opposition. As the plans have slowly moved ahead, project opponents have spoken against the project at public hearings. At one point last year, the school took out a restraining order against a neighbor who admitted to removing several pro-Castilleja lawn signs.

Because the new plans were just submitted, Castilleja staff have not yet received any feedback from those neighbors who previously voiced opposition to the project. But Brown said the school has delivered letters to the neighbors to notify them about the revisions and to invite them to offer feedback.

But even if the revisions do not address all the criticism, they aim to mitigate some of the most significant, expected impacts of the modernization project. The draft Environmental Impact Report that the city released last summer identified three "significant and unavoidable impacts." Two of these relate to traffic generated by the proposed garage. The third relates to land use. The analysis found that the project would "create land use incompatibility or physically divide an established community."

Kathy Layendecker, Castilleja's associate head of school, said the school's new garage plans aim to minimize the impact on traffic by both reducing the number of cars in it and increasing the number of points at which students would be dropped off and picked up. A prior plan envisioned a single drop-off point inside the underground garage, so all cars would have to drive through it. The new plan creates three additional drop-off points at street level, thus distributing car trips to different sides of the campus.

That said, the garage design in the new proposal is much like the one in the prior one in that it envisions a single entrance on Bryant and a single exit on Emerson, a configuration that some neighbors say could lead to collisions between cars and bicyclists on Bryant, a city-designated "bike boulevard."

Layendecker said the school's traffic engineers have analyzed the new proposal and concluded that it would result in no net new trips. The city's consultants have yet to verify that conclusion.

Even if the revised plans succeed in reducing neighborhood opposition, the project still has a long way to go before it gets a green light. The city's planning staff is currently reviewing the application, after which time it would go to the Architectural Review Board, the Planning and Transportation Commission and the City Council.

"We are an institution that's over 100 years old," Kauffman said. "We want be here for another 100 years, at least. We are looking to have a plan approved that allows the school to be forward-thinking about the future and that actually improves the neighborhood."