A proposal to allow affordable housing projects on private roads in Tisbury with a special permit has split the town’s planning board, which held a public hearing Wednesday night to discuss potential changes to zoning bylaws.

“Currently the bylaw says that any multi-family housing has to be built on a public way, and in this change you can bring forward a project that is not on a public way but a private way for consideration for a special permit,” planning board chair Ben Robinson said.

Nearly three-fourths of the roads in Tisbury are private ways, Mr. Robinson said, so the bylaw change would open up more affordable housing opportunities in the town.

To qualify for a special permit application, 25 per cent of the units would need to be deed-restricted for affordable housing and another 25 per cent deed-restricted for community housing, according to the draft bylaw change posted on the planning board website.

“It is a special permit, so it’s not by right,” said Mr. Robinson.

The planning board would review applications for their impacts on neighboring homes, the environment and public services, among other considerations. Neighbors will also have their say in the special permit hearings, Mr. Robinson told a McLellan Way resident concerned about development on the private road off Carroll Way.

Board member Connie Alexander opposed the change, saying it would put an undue burden on property owners on private roads.

“These types of high intensity, dense projects need to be placed on public roads,” Ms. Alexander said.

If she is outvoted by other board members and the currently-proposed change is placed on the town meeting warrant, Ms. Alexander said she would publicly oppose it.

“I will write a letter to the editor against it,” she said. “I will be speaking on town meeting floor.”

Board member Casey Hayward also opposed the draft bylaw change as it stands, but both she and Ms. Alexander said they were willing to work on crafting a version they would support.

“We can do better,” Ms. Hayward said.

The planning board will tackle the bylaw again on March 1, along with a proposed change to the bylaw covering accessory apartments on undersized housing lots.

The board agreed to place four other proposed changes, including a ban on time shares and fractional ownerships in residential districts, on the April town meeting warrant.

Zoning bylaw changes require a two-thirds voter majority to pass.