The legislature’s Transportation Committee kept the prospect of restoring tolls to Connecticut’s highways alive on Wednesday, but the issue remains far from settled.

The Democrat-controlled panel voted 18-13 along party lines to approve a bill that technically directs Transportation Commissioner James Redeker to establish tolls.

But the committee’s co-chairmen also said the bill is just part of a larger measure to determine if lawmakers are ready to launch a major transportation infrastructure upgrade – and if so, to determine how to pay for it.

Minority Republicans on the committee, though, were united in their opposition to tolls. GOP legislators argued they would hurt Connecticut’s economy, force congestion onto local roads near the state’s borders, and infuriate an already disappointed public that has watched $1.4 billion in state fuel tax receipts diverted for non-transportation programs since 2005.

“It is in no way a done deal,” Sen. Carlo Leone, D-Stamford, one of the co-chairmen, told the committee. “This bill is not law. This is having the conversation go forward.”

The measure approved Wednesday technically now heads to the House of Representatives. But it probably will be referred to the Finance, Revenue and Bonding Committee, and possibly to other panels.

Lawmakers also are waiting for Gov. Dannel P. Malloy, who proposed a long-term plan to invest in transportation, to appoint a panel of transportation and finance experts to study how to pay for it.

Even though many specifics are missing, the bill approved in committee Wednesday does set certain conditions.

It stipulates that any toll plan must be developed in conjunction with the Federal Highway Administration to minimize any potential loss in federal transportation grants to Connecticut.

Any toll plan also must contain legal “lockbox” language to ensure toll receipts are used exclusively for transportation programs.

Malloy wrote in a statement after the meeting that that his study panel would be appointed “in the coming days.”

The governor added that, “To continue thriving and growing as a state, to attract new companies and more jobs, and improve our quality of life, we must make essential investments in our transportation system.”

But GOP lawmakers argued in committee Wednesday that while Connecticut’s transportation needs are great, tolls aren’t the solution.

“We have to stop going the easy way and grabbing into the pockets of our residents and businesses,” said Rep. Laura Devlin, R-Fairfield.

With state wholesale and retail taxes on gasoline, Connecticut motorists have been paying some of the nation’s highest fuel taxes for the last decade, during which time the state has spent about $1.4 billion in fuel tax receipts on non-transportation programs.

Given that track record, and big looming budget deficits, Rep. Gail Lavielle, R-Wilton, asked why any legislator should advance the toll bill until Connecticut stabilizes its finances.

“I’m very reluctant to vote for something when I don’t even know what I’m voting for,” she said. “We still haven’t even managed our spending.”

Sen. Toni Boucher of Wilton, the ranking Republican senator on the Transportation Committee, said tolls would lead many motorists to abandon the highways for local roads, particularly burdening Fairfield County communities where traffic already is the heaviest in the state.

Boucher added that “tolls are highly unpopular and politically a risk for anyone voting for them.”

But Rep. Tony Guerrera, D-Rocky Hill, the committee’s other co-chairman, fired back that with improving auto fuel economy, Connecticut must prepare for shrinking gas tax receipts.

More importantly, he said, the state’s aging and overcrowded transportation network is taking a toll on the economy, and that can’t be ignored.

“Why the heck would (a business) come to Connecticut if it’s going to take you four hours to get from Point A to Point B?” Guerrera said.

The Rocky Hill lawmaker also told Republicans that opposing tolls without suggesting an alternative funding plan is irresponsible.

“Tell me (other ideas) because I’m willing to listen,” he added. “But no one’s had the guts to tell me that.”