Gov. Dannell Malloy’s plan to expand I-84 and I-95 by two lanes is unlikely to cut state traffic, experts say.

A Connecticut Department of Transportation study found that I-95 travelers could save over 14 million hours of traveling time by 2040 with the new lanes. The additional lanes are part of the governor’s 30-year transportation plan — “Let’s Go CT!” — which includes improving railways, bus lines and pedestrian walkways. However, city planning and transportation experts expressed doubts that additional lanes would decrease traffic flow.

“When you widen the highway, it might improve flow for a little while, but demand for road space will eventually even out with supply and you’ll be back at square one,” Joe Cutrufo, Connecticut advocate at the Tri-State Transportation Campaign, said.

Charles Marohn, president of the nonprofit organization Strong Towns, echoed Cutrufo’s claims. He compared attempting to cure congestion by widening highways to curing obesity by buying bigger pants.

“You’re not really getting at the fundamental problem,” he said.

Cutrufo suggested reinstituting highway tolls as a more effective way of fixing traffic congestion. Connecticut is the only state in the Northeast without highway tolls, he said, adding that traffic flow could be easily managed by charging higher tolls during rush hour and lower tolls during off-peak times.

Additionally, Cutrufo advocated for improved public transit.

“If we had more bus routes that took people from the places they live to the places they need to go, it would accomplish a lot more than widening the highway,” he said.

Widening Connecticut’s interstate highways would significantly improve the economy, the Department of Transportation study reported. The I-95 expansion could bring $15.5 billion in new business sales, add $9 billion to Connecticut’s gross state product and add a further $6.3 billion to workers’ wage income, the study found, noting that the project will cost an estimated $10.7 billion. According to the study, the I-84 expansion will be less lucrative. The two new lanes will produce $4.4 billion worth of new business sales, add $2.6 billion to Connecticut’s gross state product and add $1.8 billion to workers’ wage income. But, at an estimated $1.5 billion, the project’s cost will also be cheaper.

Doug Hausladen ’04, director of the New Haven Department of Transportation, Traffic and Parking, said the city will not directly benefit from widening either highway. However, he said he was still optimistic about Malloy’s overall vision.

“We’re extremely excited about the governor’s transportation plan, as it contains several long-term investments in New Haven,” Hausladen said.