AUGUSTA, Maine — The legislative agency whose investigation into the Maine Turnpike Authority turned up hundreds of thousands of dollars in spending on pricey hotel rooms, upscale meals, alcoholic beverages and limousines is receiving national accolades for its work.

The Office of Program Evaluation and Government Accountability will receive a Certificate of Impact award from the National Legislative Program Evaluation Society at the group’s annual conference in October. OPEGA, as Maine’s office is known, is one of 25 such agencies from across the nation that are receiving the Certificate of Impact honor.

OPEGA’s report, which was presented to the Legislature’s Government Oversight Committee in January 2011, revealed that the Maine Turnpike Authority couldn’t fully document nearly $200,000 spent on restaurant and hotel gift cards.

The Maine Turnpike Authority initially said the gift cards were donated to affiliated organizations for charitable causes, but a followup investigation by OPEGA found that the authority’s former executive director, Paul Violette, used about $155,000 worth of the gift cards himself, including some at high-end hotels and resorts in Canada, France, Italy, Bermuda and Puerto Rico.

The OPEGA investigation also raised questions about the size of the Maine Turnpike Authority’s travel and lobbying budgets.

Violette resigned from his post, which he had held since 1988, in March 2011. He’s now serving a 3½-year jail sentence and has reached an agreement to pay the Maine Turnpike Authority $155,000 in restitution.

To receive the Certificate of Impact honor from the National Legislative Program Evaluation Society, an agency has to demonstrate that its work has made an impact in the form of legislation and changes to government operations.

Following OPEGA’s Maine Turnpike Authority report, Maine lawmakers passed a bill that tightens oversight of so-called quasi-state agencies like the turnpike authority and the Maine State Housing Authority that are overseen by boards of directors, rather than directly by the Legislature.

Lawmakers also passed a law that would allow courts to revoke pensions for state employees who commit felonies. The legislation came too late to apply to Violette, who will receive his $5,000-a-month pension, although he’s forfeiting much of it through his restitution payments to the turnpike authority.

“Each and every one of us, when we joined this organization, did so because we wanted to make a difference,” said OPEGA director Beth Ashcroft. “To get this award, you have to really demonstrate that you have made a difference in one way or another. We’re all very excited about that.”

OPEGA, which has a staff of seven and began operating in 2005, also received a Certificate of Impact honor last year for its report examining emergency communications in Kennebec County.

Sen. Roger Katz, R-Augusta, congratulated Ashcroft and OPEGA staff at a Government Oversight Committee meeting Thursday.

“We are all proud of you and your staff that did that study, and particularly proud that the national society recognized that,” he said.