Hartford - An opponent of a proposed $573 million bus-only corridor between Hartford and New Britain said Monday he is optimistic that the project will be killed because full funding has yet to be approved.

Republican state Sen. Joe Markley of Southington, attending a public hearing Monday, lobbied against the nine-mile busway that state transportation officials say would reduce congestion along Interstate 84, cut pollution and improve transit time.

"I am optimistic that I'll be able to kill this project," he said. "I don't think that anything that requires environmental hearings and $600 million, much of it not committed, is inevitable."

Federal transportation officials say they already have approved $54 million. The State Bond Commission has approved nearly $90 million in bonds, with the state committing about 20 percent of the cost, or about $100 million.

However, the state cannot tap into that money until Washington signs off on a request by Connecticut for federal money, said Michael Sanders, transit administrator at the state Department of Transportation. Construction is set to begin in the fall.

Sanders acknowledged that the project will be in jeopardy until hundreds of millions of dollars in federal funding is available.

"I suppose until everyone signs on the bottom line the project could be killed," he said.

Opponents say the route would carry few bus passengers, is too costly and that the money could be better used for other transportation projects such as widening portions of I-84.