When Castilleja School received the green light last year to expand its Bryant Street campus after six years of revisions, negotiations and spirited community debate, it made a firm commitment to its skeptical neighbors: Student-population growth will not lead to traffic growth.

The school's transportation plan, which the City Council is scheduled to review on Aug. 7, includes some unusual measures that aim to achieve this goal. Juniors will be explicitly banned from driving to school, though Castilleja will be allowed to make up to five exceptions at any given time.

Forty percent of the student body will now have to live within five miles of the school. School personnel will be required to monitor surrounding streets at least once per day to ensure that staff and student do not park their cars near private homes.

In addition, every transportation report that the school submits will be reviewed by a committee of three, all of whom live in the neighborhood. The City Council chose on June 19 to appoint three residents who have been deeply critical of the Castilleja plan: Rob Levitsky, Bruce McLeod and Hank Sousa.

All three were supported by a petition from 42 neighborhood residents who live within two blocks of the school. The roster includes members Protect Neighborhood Quality of Life Now, a group that has opposed the Castilleja project, and residents who up until now have not been involved in the review process (these include Sara Cody, who as Santa Clara County's public health officer, helped orchestrate the region's response to COVID-19).

Under the conditions of approval, this Neighborhood Committee will be charged with reviewing traffic impacts and noise complaints relating to Castilleja and forwarding recommendations to the city's planning director on whether the school is compliant with the conditions of approval. The committee will also review the impacts of the school's special events and weigh in on whether the number of such events should be increased in the future.

The council will have only a limited ability to modify the new traffic plan, which consolidates and reorganizes the dozens of policies that it already approved last June, when it voted to advance the project. The council's vote followed six years of debate and more than 20 public hearings on the expansion project, which involves rebuilding most of the school's academic buildings and constructing an underground garage.

For Castilleja, the victory involved numerous compromises. These include reducing the number of "special events" at the school – those with more than 50 or more attendees – from the historical level of about 90 per year to a maximum of 50. And while Castilleja was hoping to gradually raise its student enrollment to 540 students, the approved conditional-use permit only allows it to go up to 450.

It also, however, creates a path for increasing the student population beyond 450 if Castilleja proves that it can do so without raising the number of cars making trips to and from campus. The result is a transportation-demand-management plan that members of the city's Planning and Transportation Commission have described as the most ambitious in the city's history, one that aims to keep Castilleja below its 2022 thresholds of 383 trips during the peak morning hours and 1,198 daily trips.

To ensure compliance, the plan requires Castilleja to install vehicle-counter devices at the entrances and exits of all of its drop-off-locations and parking lots, as well as its new underground garage. It will also install temporary counters on public streets around the campus, including Emerson and Bryant streets and Kellogg Avenue.

The school will keep track of both total trips and average daily trips and submit reports to the Department of Planning and Development Services three times a year until it reaches maximum student enrollment or demonstrates its ability to consistently meet its targets for daily trips and peak-hour trips. Once that happens, the frequency for Castilleja is issue reports would be reduced to twice per year.

The plan also requires Castilleja to submit every year a letter from an independent auditor attesting to the number of students enrolled in the school for that academic year. And before the school moves beyond the threshold of 450 students, it will have to hire a traffic consultant who will provide verification that at least 40% of the students live within 5 miles of the Old Palo Alto campus.

To meet its trip targets, Castilleja will bank on a fleet of free school buses and vans that will cover the cities Burlingame, San Mateo, Woodside, Portola Valley, the Los Altos region, East Palo Alto, and Menlo Park and that would be available to both students and staff. It will also have three or four vans that would shuttle students and employees to and from the Caltrain station in downtown Palo Alto.

The school will also encourage carpooling by hosting "matching parties" in neighborhoods at the beginning of the school year and by having a parent representative contact households near active carpools to offer them opportunities to join. Employees looking to find carpool partners will be able to do so by filling out a spreadsheet on the school's portal.

Castilleja will continue to offer cash incentives to employees who walk or bike to school. Its fix-it station will have staff to assist students and employees who need help maintaining their bicycles.

To reduce parking impacts to the immediate neighborhood, the school has leased parking spaces at two remote locations: First Presbyterian Church and University AME Zion Church. According to the school's new plan, it leases 25 spaces at First Presbyterian for employees, allowing them to park and walk to campus. The University AME Zion Church spaces are for both students and employees and the school has a shuttle that runs between the church and the school in the morning and at multiple times during the afternoon.

To boost its various efforts, Castilleja will send information to families about its various transportation-demand-management programs at the start of every school year and in the second semester, according to its plan. The school will also provide all students, parents and guardians with a handbook detailing its traffic rules and consequences for non-compliance. Everyone will be required to sign a form attesting that they have received and read the handbook.

"All students and parents are encouraged to carpool, ride Caltrain, and use the school's buses and shuttles," the school's TDM plan states. "Students who live near campus are encouraged to walk or ride a bike to school."

Those who drive, meanwhile, will be required to register their cars at the start of every school year and to receive ID tags. Registered cars will be identified by stickers affixed to the windshield.

School employees will be required to commit to one of three actions at least four times per week: commuting by means other than a car, carpooling with two or more non-family members or parking in a remote parking lot. Those that cannot do so will be required to sign up to help with traffic duty on days when they need to park on campus, according to the plan.

The unusually ambitious nature of the transportation plan reflects the tense history between the school and the surrounding neighborhood. Castilleja's critics have frequently invoked the school's history of failing to abide by its enrollment cap, which prompted the city to issue a $265,000 fine and demand gradual reduction.

Many had argued that the school's proposed garage is incompatible with the residential nature of the surrounding neighborhood and suggested that Castilleja explore satellite locations for its expanding student population.

Supporters of the project have countered that Castilleja has a proven record of reducing its traffic impacts and argued that the project would create a more environmentally sustainable campus while providing more educational opportunities for girls in grades six through 12.

Jim Poppy, a Melville Street resident who has opposed Castilleja's project, argued in a letter to the council last week that the new transportation plan doesn't go far enough in ensuring that students will not park in the neighborhoods. He asked the city to require all students who register their cars to submit photo IDs and license plate numbers, which will be available to the Neighborhood Committee. The idea, he wrote, is to make sure that people won't simply refrain from applying their stickers to their vehicles.

"Are we to trust all students and parents will apply their stickers to their vehicles? To assume this will happen is sheer folly," Poppy wrote.