AUSTIN - The chairman of the Texas Senate transportation committee said he’s certain lawmakers would oppose any effort by the Texas Department of Transportation to toll existing interstate highways.

The department is lobbying Congress to pass a federal law that would allow the state to “buy back” parts of existing interstates and turn them into toll roads.

“I think it’s a dreadful recommendation on the part of the transportation commissioners here in Texas,” said Sen. John Carona, R-Dallas.

“I feel confident that legislators in Austin would overwhelmingly be opposed to such an idea,” he said. “The simple fact is that taxpayers have already paid for those roadways. To ask taxpayers to pay for them twice is untenable.”

The department’s plan, which is outlined in a report called “Forward Momentum,” also suggests tax breaks for private company investment in projects to convert interstates to tollways.

The report seeks changes in federal law to allow the use of equity capital as a source of transportation funding. It also calls for altering the tax code to “exempt partnership distributions or corporate dividends related to ownership of (a) toll road from income taxation.”

U.S. Sen. Kay Bailey Hutchison said in a statement Friday that she opposes the transportation department’s plan.

“Texans should never have to pay twice for a highway,” her statement said.

Transportation Department spokesman Chris Lippincott noted that Texas law would require approval by county commissioners and taxpayers in a referendum if the state wanted to convert interstate highways into toll roads.

Robert Black, a spokesman for Gov. Rick Perry, said the report doesn’t contradict Perry’s repeated commitment that free highways will not be converted to tollways. That wouldn’t change without the approval of local voters, he said.

Lippincott said he wouldn’t expect the report, which was released in February, to come as a surprise to lawmakers. It was discussed at four public meetings and the department sent a link to the draft report last December to all state lawmakers, he said.