PROVIDENCE, R.I. — Gov. Gina Raimondo signed into law on Thursday a bill that will impose a toll on big-rig trucks traveling highways through Rhode Island, culminating an eight-month debate that captivated the nation's smallest state and infuriated its truckers.

The Democrat wasted no time after the bill passed through both chambers of the General Assembly and landed on her desk Thursday evening. She signed it in a hastily arranged ceremony only moments after lawmakers adjourned.

State senators voted 25-12 after a three-hour debate Thursday to approve the highway truck tolls that would finance a 10-year plan to repair deteriorating bridges. The House of Representatives had voted 52-21 on Wednesday night to pass the bill after seven hours of lively debate.

Toll proponents argued that the bill targets out-of-state truckers who cause the most damage to roads. Federal records show the state has the highest percentage of structurally deficient bridges. The plan proposes charging up to $20 for an 18-wheeler to cross the state along Interstate 95.

"When they come through Rhode Island, they don't even stop to get a coffee," said the bill's sponsor, Senate Majority Leader Dominick Ruggiero, a North Providence Democrat, as he closed the debate Thursday. "They just keep on going and wreck our roads."

Construction labor unions and trade groups eager for the surge of public works contracts backed the measure.

Democrats hold a supermajority of both chambers but several joined Republicans in voting against the bill. They sided with local trucking companies who said that they would be most burdened by the tolls.

"We are singling out an industry stating that they are the cause of the damage to our bridges," said Sen. John Pagliarini, a Tiverton Republican elected late last year after campaigning against the tolls. He said as much of the blame goes to poor winter salting practices, bad management at the state department of transportation and other heavy vehicles such as dump trucks that will be exempt from the tolls.

Raimondo said the measure provides a more sustainable source of money to fix deteriorating infrastructure. That will provide more confidence for businesses that want to expand in the state, she said.

"We're on our way to safe roads and bridges, higher-quality roads and bridges," she said. "It's good for the business community and it's good for Rhode Island."