AUGUSTA, Maine — Lawmakers on Friday declined to order a probe of the Maine Turnpike Authority’s pending proposal to raise tolls, saying the authority’s executive director has been transparent about the toll increase proposal and made the case for it.

Members of the Legislature’s Government Oversight Committee were considering a request from Sen. Margaret Craven, D-Lewiston, to have the Legislature’s investigative arm look into the turnpike authority’s proposal to increase tolls in order to generate $26 million in additional revenue annually.

Craven said the proposed toll hikes fall disproportionately on the backs of residents of the Lewiston-Auburn area and western Maine, and she said she’s concerned that high toll costs could cause businesses in that region that need to transport goods along the 109-mile highway to be at a disadvantage.

“I don’t want businesses to move out of Lewiston because they can’t afford to operate there,” Craven said Friday.

But Craven’s colleagues on the oversight panel said there was no need for an investigation.

“I understand the equity piece, but under the circumstances, [the Maine Turnpike Authority is] doing as much as they can, and I think the director has said that it’s not done yet,” said Sen. Nancy Sullivan, D-Biddeford.

Maine Turnpike Authority board members meet on July 19 to vote on the toll increase. Changes would likely take effect Nov. 1.

The current proposal favored by turnpike authority staff — one of 10 options the authority considered — would hike tolls by $1 at the toll plaza in York, 75 cents at toll plazas in New Gloucester and West Gardiner, and 50 cents at Wells and Gray. The proposal also would raise the per-mile rate for users of the E-ZPass toll transponder to 8 cents from the current 6.7 cents.

Peter Mills, executive director of the turnpike authority, conceded Friday that residents of the Lewiston-Auburn area have long been subject to toll-related inequity. The Maine Turnpike opened in 1947, before the federal government began constructing the interstate highway system in Maine. Federal law generally prohibits tolls on those interstate highways, Mills noted.

“That’s an unfairness that has always plagued, and will for some years, plague the Lewiston-Auburn community,” he said, suggesting that drivers concerned about inequitable tolling purchase E-ZPass transponders and pay a per-mile rate for using the highway.

In her formal request letter to have the Office of Program Evaluation and Government Accountability, or OPEGA, investigate the toll hikes, Craven wrote that she’s surprised to see any proposal for an increase now, “given the past problems with the Turnpike Authority and the inefficiencies we discovered.”

If lawmakers had ordered an OPEGA review of the toll increases, it would have been the office’s second probe of the Maine Turnpike Authority in recent years. An examination by the agency in 2010 turned up more than $200,000 in unaccounted spending, a finding that ultimately led to a theft conviction and prison sentence for Paul Violette, the authority’s former longtime executive director.

Mills said the Maine Turnpike Authority needs to generate $26 million annually in additional revenue to fund $113 million in bridge repairs on northern sections of the 109-mile highway over the next five years, pay for $82 million in paving and other road improvements and pay off debt from a highway widening project completed in 2004.

Revenue growth for the turnpike has largely leveled off, he said, and the turnpike needs to take in a certain amount of revenue in order to comply with the terms of its debt and avoid a default. The turnpike authority takes in about $103 million annually from tolls and another $3 million each year from operating its service plazas.

“We have been able to bring in our construction contracts at less money than we thought; we reduced costs more rapidly,” Mills said, “but we’ve been victimized by the recession.”

Some of the road improvements on deck include major work on Exit 80 in Lewiston and a high-speed toll in New Gloucester, said Mills. He added that he has begun conversations with turnpike authority board members about raising the speed limit to 70 mph on much of the highway and installing a high-speed toll in West Gardiner.