ATLANTA - Georgia Democrats took the wraps off a proposal Thursday to overhaul state transportation funding and slammed Gov. Sonny Perdue, saying he's failed to ease the state's worsening gridlock.

Democrats, who are in the minority in the House and the Senate, said the state is missing out on millions of dollars in federal aid because it is failing to adequately fund road, rail and other infrastructure improvements.

They singled out federal rapid rail money and highway stimulus funds that would have required a state investment.

They are pushing a two-part plan.

One proposal would allow counties to band together and ask voters to hike the state sales tax by one cent to pay for transportation. The proposal is similar to a GOP-backed plan that's failed to win approval the last two years.

The second part of the Democrats' proposal would take the so-called fourth penny collected as part of the tax on motor fuel and funnel it into road and other infrastructure improvements. Most of the revenue collected by the state tax on gasoline already goes to fund transportation. But one penny goes into the state general fund.

Both proposals are constitutional amendments, so they would require two-thirds approval in the House and the Senate. They would then require voter approval at the ballot box.

Perdue spokesman Bert Brantley said dedicating that additional penny to transportation would strip about $137 million away from the state treasury.

"That's roughly the equivalent of 3,000 teachers' salaries," he said.

Brantley disputed Democrats' argument that Perdue hasn't been aggressive enough on transportation funding. Perdue focused last year on cleaning up management at the state Department of Transportation, insisting that before he sent the agency more money he wanted to ensure it would be well spent.

Perdue has also included $300 million in bonding for state transportation projects in his budget for the next fiscal year.

State Sen. Tim Golden, a Valdosta Democrat, argued Thursday that for the last eight years Georgia's leadership had "led us on a road to nowhere."

About 30 Democratic legislators crowded into the news conference, including Senate Minority Leader Robert Brown of Macon and House Minority Leader DuBose Porter of Dublin.

State Sen. Jeff Mullis, chairman of the Senate Transportation Committee, noted that the Democratic sales tax proposal mirrors the GOP plan which is still in a conference committee.

"Transportation is not a partisan issue. We should all come together, as we did in the Senate, to work on solutions that are best for all Georgians," the Chickamauga Republican said.