Hartford - Tolls were eliminated on Connecticut's highways 30 years ago, but debates and studies on how to replace the lost revenue have continued. Now the state Department of Transportation is taking another look at establishing electronic tolls to reduce highway congestion.

The agency met twice last week to bring together national and local experts to discuss how tolls could reduce congestion. Transportation planners have devised congestion pricing to improve traffic, with different rates charged to motorists to avoid rush hour and instead drive during off-peak hours or on less-crowded roads.

A key state lawmaker has pushed for tolls to raise more revenue and said he welcomes talk about tolls even if the intent is to prod motorists to leave their cars at home and take the train or bus.

"It is about raising more revenue to be honest with you, and it's about people saying, 'I don't want to pay a toll and take Metro-North or another bus transit system,"' said Antonio Guerrera, House chairman of the legislature's Transportation Committee.

Lawmakers and a succession of governors have refused to re-impose tolls in Connecticut after a tractor-trailer crash at a Stratford toll booth in 1983 killed seven people. Electronic tolls eliminate toll booths and instead use car transponders that record travel and debit a registered motorist's account.

"Traffic congestion affects everyone - undermining the economy and detracting from citizens' quality of life," the Department of Transportation said in announcing the meetings.

Traditional ways to reduce traffic jams - such as costly projects to widen highways - can no longer be considered a solution, officials said. That has led to suggestions for different approaches such as tolls to prod changes in commuters' behavior.

The legislature's latest review, which should be completed by the end of the year, will consider special lanes with overhead tolls for commuters who want to avoid traffic bottlenecks.

"Those who don't want to pay the toll wouldn't have (to), but they would also be stuck in traffic," Transportation Department spokesman Judd Everhart said.

Electronic tolls are not new to Connecticut. A 2009 report for a state transportation study group outlined the possibility of express lanes charging tolls on Interstate 95 at Branford to the Rhode Island line and Interstate 84 from Waterbury to New York state, requiring trucks to pay tolls.

Oz Griebel, who headed the state transportation study in the early 2000s, said tolls will eventually return to Connecticut, but not to reduce traffic.

"The ultimate motivator will be less about congestion mitigation than about revenue goals," he said.

Improved vehicle fuel efficiency and more electric and hybrid trucks and cars have slowed the rise in gasoline sales and state and federal gas tax revenue that finances road and bridge maintenance and construction. For the state's budget year that ended June 30, 2013, gas tax revenue was $501.3 million, up only 1.7 percent from the previous year.

Motor fuel tax revenue was less in the same period a decade ago, $458 million, but it rose by a more robust 6 percent.

Also spurring the state to consider tolls is a proposal by President Barack Obama's administration to loosen restrictions on tolling federal interstates. States are barred from tolling federal interstates except if the money is used to add lanes or otherwise increase capacity. Tolls also can be used if they predate the launch of the federal interstate highway program in 1956.

Guerrera said an alternative would be to increase gas taxes "to levels that are absurd."

Whatever the eventual revenue fix is, debate over tolls and gas taxes is never easy, he said.

"It does become a political hot potato," Guerrera said.