After neighbors of Vineyard Montessori School objected earlier this month to the size and scale of a proposed new preschool building on the Vineyard Haven campus, head of school Deborah Jernegan and attorney Ross Seavey presented a modified design to the Martha’s Vineyard Commission.

The updated plan presented on Thursday lowers the building’s ridge height by more than two feet, with corresponding adjustments in roof pitches and window heights.

Responding to neighbors’ complaints about traffic congestion caused by parents bringing their children to and from the campus, the applicants offered to add a carpooling sign-up program to the school website, post “No Idling” signs on the property and, if necessary, adjust pick-up and drop-off times to avoid traffic back-ups.

Vineyard Montessori School also will join neighbors in petitioning the Tisbury select board to ban parking on one or both sides of Tashmoo avenue, and/or to designate the area a school zone with reduced speed limits, according to an offer letter presented at Thursday’s commission meeting.

A preliminary landscaping plan submitted this week includes plantings intended to screen views and noise, Mr. Seavey told the commission. A drainage plan for the expansion is still in the works, but has been delayed by the company contracted to do the job, he said.

“They’re all so busy [and] weren’t able to turn around the drainage plan despite us nagging them pretty consistently over the past couple weeks,” Mr. Seavey said.

While Ms. Jernegan expects to hire three more teachers once the expansion is complete, MVC housing planner Laura Silber said the school is not required to provide housing mitigation under commission rules.

“Vineyard Montessori qualifies as a nonprofit organization... that can establish to the commission’s satisfaction that the principal population to whom they provide social services is the same as those who qualify for affordable or community housing,” Ms. Silber said.

“The information we received today is that 53 per cent of the families with children in care of Vineyard Montessori School receive public subsidies, [including the] SNAP supplemental nutrition plan, the WIC supplemental nutrition program for women, infants and children, low-income home energy assistance programs, MassHealth, Medicaid or [the state] children’s health insurance program,” she said.

Founded in 1975, the school currently has 60 preschoolers, 18 toddlers and 15 elementary school students in its two campus buildings, while another 15 elementary and middle school students attend classes in rented space on Church street.

The expansion would consolidate all of the student body on campus, adding up to 29 more children for a total of 27 toddlers, 80 preschoolers and 30 students in elementary and middle school grades.

Commission chair Fred Hancock closed the public hearing Thursday but kept the written record open until 5 p.m. Feb. 22.

Two other items initially placed on Thursday’s agenda were continued without testimony.

An application to move the historic Caleb Prouty house from downtown Vineyard Haven to a property on Lagoon Pond Road has had its hearing shifted to March 7 and a development proposal on Uncas avenue in Oak Bluffs will return to the commission April 4.

Also Thursday, the commission approved a land use policy with updated maps and discussed plans for the 50th anniversary of the MVC. An exhibition at Featherstone Center for the Arts next month will celebrate the commission’s history, Mr. Hancock said.

Past and present commissioners will gather for a special event at Featherstone March 14 to commemorate the date when state lawmakers signed legislation creating the Martha’s Vineyard Commission in 1974.