The Martha’s Vineyard Commission conducted a proper review and acted within its authority when it approved the roundabout traffic project earlier this year, the commission said in a formal response to a lawsuit seeking to block the decision.

The response, dated Dec. 23, was filed in Dukes County superior court, where the towns of West Tisbury and Edgartown sued the MVC earlier this month.

The towns hope to invalidate the commission’s decision and force a more thorough review of the traffic project, which targets congestion at the blinker intersection of Edgartown-Vineyard Haven and Barnes Roads.

But in a six-page response, the commission’s lawyers denied the lawsuit’s assertions that the MVC disregarded its own regulations, rushed the project through without proper public review or relied on incomplete designs and data.

It said the commission “had all the necessary information before it on which to base a decision.” The commission had three traffic studies and a complete set of design plans available to it, and made public findings that complied with state law, according to the response, filed by attorneys Brian M. Hurley and Gareth I. Orsmond, of the Boston firm Rackemann, Sawyer & Brewster.

Those findings “were amply supported by the evidence presented at the public hearing,” the response said. “MVC acted within its statutory authority in approving a proposal submitted by Oak Bluffs and designed by the Massachusetts Department of Transportation.”

It also denied the project will have any “direct and substantial impacts” on traffic management in either West Tisbury or Edgartown.

In particular, Edgartown “had every opportunity” to participate in the public hearing process “but did not do so,” said the filing. In conclusion, the commission’s lawyers questioned the two towns’ legal standing to sue, saying neither is a “person aggrieved within the meaning” of the law.