Rhode Island’s controversial truck-tolling plan is now the target of a federal lawsuit filed by the American Trucking Associations and three motor carriers. The suit, filed on July 10, contends that the state’s RhodeWorks truck-only toll scheme is unconstitutional.

Under the RhodeWorks plan, which was signed into law back in 2016, 18-wheelers will pay up to $20 to cross the state traveling on Interstate 95. A single truck will be capped at paying $40 a day.

The tolls are intended to finance a 10-year plan to repair deteriorating bridges in the Ocean State; Rhode Island has the highest percentage of structurally deficient bridges in the country. The tolls, to be collected electronically via 14 gantries, are expected to bring in around $45 million a year once they are up and running.

“Since RhodeWorks was first proposed, the trucking industry has been strong and united in opposition to this extortionate plan,” said ATA President and CEO Chris Spear in a statement. “We’ve warned politicians in Rhode Island that these truck-only tolls were unconstitutional and should be rolled back. It is unfortunate that Governor [Gina] Raimondo and her administration did not heed those warnings, but now we will see them in court.”

In the suit, ATA and Cumberland Farms Inc., M&M Transport Services Inc. and New England Motor Freight argue that the RhodeWorks plan violates the U.S. Constitution’s Commerce Clause by discriminating against out-of-state trucking companies and by designing the tolls in a way that does not fairly approximate motorists’ use of the roads.

“This toll regime was designed to, and does in fact, impose discriminatory and disproportionate burdens on out-of-state operators and on truckers who are operating in interstate commerce,” the complaint states. “By design, the tolls fall exclusively on the types of trucks that are most likely to be engaged in the interstate transport of cargo, while exempting automobiles and the smaller vehicles that are relatively more likely to be engaged in intrastate travel.

In addition, the suit holds that the toll plan “also limits the tolls collected from trucks that make multiple trips within Rhode Island in a single day, a feature that was expressly intended to, and does in fact, provide disproportionate benefits to Rhode Island operators and those engaged in intrastate commerce.”

Related: Rhode Island's Truck Tolls Remain Unpopular with Trucking Groups