Toll-weary motorists just might have the last laugh.

A drivers advocacy group filed a lawsuit yesterday against the Port Authority, claiming the agency’s recent toll hikes violate federal laws and need to be rolled back.

If successful, the suit filed by AAA would halt the PA’s plans to hike tolls over the next four years, which would increase the cash toll to $15 by 2015.

The group claims the hikes are illegal because they are going in part to fund the rebuilding of the World Trade Center.

Federal law requires that toll hikes “have a functional relationship to transportation,” the group said.