HARTFORD — Senate Republicans in Connecticut unveiled an alternative transportation plan on Thursday that doesn’t rely on tolls or tax increases but includes many of the same projects proposed by Democratic Gov. Ned Lamont.

The 10-year, nearly $18 billion FASTR CT initiative from the minority party in the state Senate comes a day after Lamont pitched his 10-year, $21.3 billion CT2030 plan to Senate Democrats, who liked many of the projects but not the fact it includes 14 tolls on bridges across the state.

“We believe this is the way to go for transportation,” said Senate Minority Leader Len Fasano, R-North Haven, noting that Senate Republicans “simply cannot support tolls.”

It’s unclear whether the Senate GOP’s plan will ultimately lay the groundwork for a political compromise on an issue that has vexed the state of Connecticut for years. Senate President Martin Looney, D-New Haven, welcomed the plan and praised Fasano for trying to find a bipartisan solution.

“Connecticut succeeds best when both parties work together,” said Looney, adding how Senate Democrats were analyzing the proposal. But Lamont, who said he appreciated Fasano’s efforts to “partially fund much-needed infrastructure investments,” raised concerns about the funding arrangement.

Like Lamont’s plan, FASTR CT relies partly on low-cost borrowing from the federal government to help pay for road, bridge, rail, port and bus improvements. But instead of using toll money to help pay off those loans, like Lamont’s initiative, it banks on a complicated plan to financially stabilize the state’s dedicated transportation fund, which is facing insolvency.

The GOP proposal transfers a portion of the state’s budget reserve account, $1.5 billion, and uses that money to pay down state pension debt. While Looney appeared somewhat receptive to the idea, noting the state’s reserves are currently at a historically high level, Lamont called it a “risky proposition that requires serious evaluation.” House Speaker Joe Aresimowicz, D-Berlin, who supports tolls, said he also has concerns about “such a significant raid” on the reserve account.

Fasano contends that using surplus funds to pay down pension debt will free up enough cash in the state’s main spending account — the general fund — to cover the cost of fringe benefits for certain state workers that are currently paid through the transportation fund. After that and other changes, the fund would theoretically be financially strong enough to pay off the low-cost federal loans.

Toll opponents welcomed a plan that doesn’t rely on the fees on drivers. But they acknowledged the complex details of how to pay off the federal borrowing will still need to be hammered out by lawmakers and Lamont.

“We see this plan as a good step toward reaching a bipartisan solution that doesn’t levy another tax on the working people of Connecticut,” said Patrick Sasser, founder of No Tolls CT.

Don Shubert, president of the Connecticut Construction Industries Association, said his group welcomes the “very technical discussion” on how to pay for much-needed transportation improvements on the long term.

“We’re hoping that the entire legislature stays engaged at this level because this is a level that we’ve been waiting for, for a long time,” he said. “It’s very encouraging to see this discussion.”