PROVIDENCE, R.I. — The U.S. transportation secretary visited southern New England on Thursday to warn of the danger of letting a federal fund for road and bridge repairs run out of money.

The Highway Trust Fund, used to reimburse states for highway and transit projects, is on track to become insolvent this summer unless Congress acts, because its main revenue source, the federal gas tax, isn’t bringing in enough money.

In two separate gatherings, Transportation Secretary Anthony Foxx met with Rhode Island Gov. Lincoln Chafee, Connecticut Gov. Dannel P. Malloy and both states’ congressional delegations. Foxx said he is hoping to rally the public to push Congress to address the shortfall in the Highway Trust Fund, saying the looming insolvency should matter to every American.

The Rhode Island Department of Transportation says it has already delayed the award of 20 projects, worth a total of about $67 million. These include replacing the Great Island Bridge in Narragansett and two bridges in East Providence, as well as resurfacing roads in Providence, Pawtucket, Newport and North Kingstown.

Rhode Island spends about $20 million a month on active road and bridge projects, including current work to replace the Providence Viaduct and paving on I-295, said state DOT Director Michael Lewis.

Eighty percent or more of that cost is reimbursed by the federal government. The state can’t commit to new projects without knowing it will be paid back, Lewis said.

Work on existing projects could slow or stop if Congress waits months to replenish the fund, Lewis said. The state receives a total of about $220 million a year in federal funds for highway, bridge and transportation projects.

In Connecticut, Malloy said the state can afford to cover the cost of various ongoing transportation projects for about a month. But if the impasse lasts longer, Malloy said the state will not be able to go out to bid with 85 projects planned for next year. The list includes highway, mass transit and rail improvements, such as replacement of catenary wires along the New Haven Line.

Malloy said existing projects could also be affected if the trust fund problem isn’t fixed.

Foxx told states this week to expect a 28 percent cut on average in funding for the highway programs beginning Aug. 1.

“It’s very frustrating to be honest with you,” Foxx said during a news conference at the Rhode Island Statehouse. “Because every generation of Americans, every single one, has left a better country behind them. And we are at risk of pulling up the drawbridge. And I will not let that happen quietly.”

U.S. Sen. Jack Reed, D-Rhode Island, said partisan gridlock in Washington is “threatening to put the brakes on highway spending and transit spending and jobs.”

“We’re on the cusp of a disaster,” he said.