Providence — A proposed toll on commercial vehicles would pay for a $700 million revenue bond to repair Rhode Island's deteriorating bridges, state officials announced Wednesday.

Gov. Gina Raimondo and leaders of both legislative chambers announced the proposal as part of a $4.8 billion infrastructure plan called RhodeWorks.

A budget amendment to be submitted this week would total of $1.1 billion, the amount of the bond plus $400 million in federal funds for an express bus lane at the interchange of Route 6 and 10. There is already $3.7 billion budgeted for the Department of Transportation.

"Right now, in Rhode Island, about a quarter of overpasses and bridges are structurally deficient," Raimondo said. "The longer we wait to fix the problem, the more expensive it is."

Raimondo said failing to begin work right away would cause the eventual cost to balloon by $1 billion.

Rhode Island is ranked last in the nation in overall bridge condition, officials said. The project proposes to fix more than 150 structurally deficient bridges in the state and repair an additional 500, while creating 12,000 job-years over the next decade.

The upfront bond will shorten the time it takes to repair the bridges, said Peter Alviti, director of the Department of Transportation. The bond would be floated as soon as possible, he said.

The tolls would only apply to large commercial trucks, the smallest being a three-axle vehicle, officials said.

"The fact of the matter is, those are the trucks that cause 90 plus percent of the damage to our highways and bridges," Raimondo said. "They also benefit the most from well-maintained bridges and roads."

The tolls are expected to generate $70 million to $100 million annually to repay the bond, Alviti said. He said officials haven't yet determined what the fees will be, but that they'll likely be in the mid-range of what other states in the Interstate 95 corridor assess. Pennsylvania assesses a $182 fee for its turnpike, while New Hampshire assesses a $6 fee.

Between 17 and 20 gantries will be located at bridges along the state's five highways, Alviti said, and drivers will be electronically tolled at each bridge. The gantries will cost between $2 million and $3 million each to construct, he said. The gantries would be up as soon as next summer, with tolling beginning sometime the following year.

House Speaker Nicholas Mattiello and Senate President Teresa Paiva-Weed said members in both chambers have been supportive of the proposal.