West Tisbury will join Edgartown in a legal challenge of the Martha’s Vineyard Commission’s decision to approve the roundabout.

At the West Tisbury selectmen’s meeting Wednesday, selectman Richard Knabel said the project had generated a “staggering amount of opposition on the Island.”

“I and many other people are now disappointed in both the process and the outcome,” Mr. Knabel said. “The design concept that the MVC has just approved is just that. It’s a design concept; it’s not a final plan. We have no idea what the final plan is going to look like or what the final cost will be.”

Selectman Cynthia Mitchell agreed.

“I thought the process was flawed, flawed and flawed and I think an appeal maybe stands the possibility of succeeding because of that,” she said. “Who was not served in this was the public.”

Selectman Jeffrey Skipper Manter reluctantly agreed to back the challenge, but noted that the cost of the appeal would be borne by the taxpayer.

“Getting involved in a lawsuit that pits one municipal agency against another is a little uncomfortable to me,” he said.