The federal Government Accountability Office is investigating toll increases on area Delaware River bridges as part of a broader look at toll increases and tolling authorities.

The GAO, the investigative arm of Congress, wants to know how toll increases are determined and why.

The agency has asked the Delaware River Port Authority and other toll agencies for information about recent hikes.

Tolls last went up on DRPA's four bridges on July 1, 2011, to $5 for cars, from $4. Tolls had been raised to $4 in September 2008, from $3.

Motorists have criticized toll hikes at the DRPA, complaining that much of the revenue went to pay for the agency's debt and economic-development projects unrelated to the bridges.

The Delaware River Joint Toll Bridge Commission, the bistate agency in New Hope that operates seven toll bridges, including the I-80 span between Pennsylvania and New Jersey, received a similar request from the GAO, spokesman Joe Donnelly said.

The toll inquiry was triggered by U.S. Sen. Frank Lautenberg (D., N.J.), who has criticized recent toll increases on bridges and tunnels operated by the Port Authority of New York and New Jersey.

Lautenberg wrote the GAO in March, asking it to examine toll hikes, use of toll revenue, and "the transparency and accountability of the funding and management decisions" at interstate tolling authorities.

GAO spokesman Ned Griffith said recent toll increases "have raised questions about whether transportation authorities are remaining accountable to their congressionally approved compacts."

GAO is looking at three areas, Griffith wrote in an e-mail:

"(1) To what extent do interstate compacts and related legislation establish priorities and oversight processes for transportation authorities?

"(2) How have transportation authorities set tolls, spent toll revenue, and made these decisions transparent?

"(3) To what extent have the actions of transportation authorities been consistent with interstate compact priorities and leading practices for toll-setting decisions?"

Griffith said GAO investigators had just begun their work and could not predict when they would report their findings.

DRPA board members, including Gov. Corbett, debated Wednesday how to respond to the GAO's request for toll information.

Rob Teplitz, representing Pennsylvania Auditor General Jack Wagner on the board, urged that the DRPA's new inspector general be the main liaison with federal investigators.

Corbett, who chairs the DRPA board, said chief executive John Matheussen and DRPA lawyer Danielle McNichol should meet with GAO investigators. At Teplitz's urging, he agreed Inspector General Thomas Raftery should be included.

"I think we have a very good story to tell . . . about how we increase tolls," Matheussen said. "We didn't just do this on a whim."

The DRPA is $1.2 billion in debt, and more than 40 percent of toll revenue goes to debt payment and debt-related costs.

Much of that debt accumulated during the last 15 years, as DRPA spent about $500 million on economic-development projects, such as sports stadiums, museums, and concert halls, after the 1992 approval by Congress and President George H.W. Bush of economic-development powers for the agency.

All of the money borrowed for economic development has been spent, and the DRPA board has promised to end the practice of spending on non-transportation-related economic development.

On Wednesday, DRPA officials reiterated that financial and governance reforms approved two years ago would be made by the end of 2012.

In 2010, the DRPA board responded to demands of Pennsylvania and New Jersey governors with a well-publicized flurry of new rules designed to make the agency more accountable, transparent, and fair.

But "most of the reforms have not been incorporated into the authority's bylaws and standard operating procedures," Raftery wrote in a report in May.

DRPA spokesman Tim Ireland said Wednesday that working groups were meeting four times a month to implement the reforms, which will require changes in DRPA bylaws and resolutions.

A motorists' organization said Wednesday "the changes can't come soon enough."

"We've already been waiting two years for the change to happen," said Jenny M. Robinson, spokeswoman for AAA Mid-Atlantic. And she said the GAO investigation of toll increases also "serves to underline our longstanding concerns. We hope the feds can shine a light on last year's toll hikes."

Contact Paul Nussbaum at 215-854-4587 or