Drivers could pay tolls on Maine’s interstates under a pair of proposals that lawmakers are considering, but transportation officials counter that federal law prohibits such a move. Democratic Rep. Michel Lajoie of Lewiston proposes that when any section of I-295 is expanded to three lanes, the entire road should be tolled at a rate commensurate with I-95, or the Maine Turnpike. A separate bill calls for a task force to study options for imposing tolls on portions of Maine’s interstate highway system to pay for road improvements. But the state Transportation Department says federal law clearly prohibits tolls on highways that are built and maintained with federal money. Federal highway officials have told the state DOT that it would take an act of Congress to add tolls on I-95.