The plan to build a roundabout at the intersection of Barnes and Edgartown-Vineyard Haven Roads will now be reviewed by the Martha’s Vineyard Commission as a development of regional impact (DRI).

The roundabout has been the subject of a decade of planning and a bid is set to go out this fall. But commission members said on Thursday night the project plainly has regional impact, citing potential impacts on the intersections at either end of the Edgartown-Vineyard Haven Road.

The issue drew lively debate Thursday.

“This project is very far along and the TIP [state transportation improvement program] money has been planned for the next two years,” commissioner Holly Stephenson said, referring to the $1.1 million from the state program earmarked for the project. “Why wasn’t this referred some years ago?”

Oak Bluffs selectmen began studying the blinker intersection in 2001 by hiring an independent firm which recommended a roundabout. After a number of accidents selectmen made the intersection a four-way stop in 2003 and approved in principle the construction of a roundabout. In 2004 the selectmen asked the MVC to study the intersection and in 2006 the commission released a report recommending a roundabout. In the same year the town held three public hearings about the proposal; the state Department of Transportation held another public hearing this spring.

In June the roundabout was referred to the MVC for review by the West Tisbury selectmen, who feel more public discussion is in order. On Thursday night West Tisbury selectman Richard Knabel, appearing with his fellow selectman Cynthia Mitchell, acknowledged that the referral came late but argued that the intersection was of obvious regional impact.

“If this intersection is not an integral part of the regional transportation system for the Island, then I don’t know what is,” Mr. Knabel said. “If this is not a DRI, I really think I need someone to explain to me why it isn’t.”

Some commissioners rejected the claim that there had not been enough publicity about the project. “If people don’t go to the public hearings I don’t have a lot of sympathy for them,” said commissioner Chris Murphy.

“At this point it seems clear to me you have essentially a done deal and whether you like the deal or not . . . the time has passed for another body to completely review this,” he said.

Commissioner Leonard Jason questioned John Diaz of the construction firm Greenman Pederson Inc. about whether the roundabout, by easing traffic in the heart of the Island would contribute to longer waits in Edgartown and Vineyard Haven.

“It could,” said Mr. Diaz. “Whatever you do is going to impact someone.”

“That’s the issue,” said Mr. Jason. “It appears to impact other communities.”

There were other reactions to the proposed traffic improvement.

“Please leave well enough alone, the Vineyard is almost gone as it is,” said Roberta Bradford Mendlovitz. “We do not need a fancy roundabout to cause unnecessary confusion and destruction in a crucial area of our disappearing homeland.”

Tom Currier from the department of transportation said a commission review could delay the project but was unlikely to put it in jeopardy.

Four of the five Oak Bluffs selectmen appeared at Thursday’s meeting to defend the project.

“From my standpoint this is about safety, it’s always been about safety and only about safety,” said selectman Greg Coogan, who noted that the drawbridge between Oak Bluffs and Vineyard Haven was not referred to the commission. “We’ve involved the commission since day one and we’ve made this quite a public process,” he said.

Selectmen Walter Vail agreed.

“This is not just a solution to today’s problem but this is a 20-year solution for a growing traffic problem on the Vineyard,” he said. “What happens on either end is up to Edgartown and Vineyard Haven to deal with . . . [The commission’s report] has been available for five years and for the public to say that they didn’t know what the benefits of the intersection are is just crazy in my view.”

Commissioner James Joyce agreed.

“This thing has been discussed over and over again. I don’t think we need to discuss it anymore. People are just afraid of change.”

But commissioner Doug Sederholm said despite the eleventh hour the commission is chartered to review exactly this type of project.

“I think it’s obviously regional and that’s our job,” he said.

A motion not to review the project as a DRI failed 5 to 8. A subsequent vote to review the project passed 10 to 3.