Mayor Bloomberg is counting on a newly amended congestion pricing bill to win over skeptical lawmakers and push his traffic plan over the top.

Under the revised bill, submitted Saturday in the Senate, the Port Authority would have to contribute $1 billion to the Metropolitan Transportation Authority’s five-year capital plan. Many lawmakers were concerned that New Jersey commuters who enter the city through Port Authority-managed tunnels and bridges would not pay their fair share of congestion pricing compared with New York residents, as drivers who pay tolls to enter the city would have some of their congestion pricing fees offset under the proposal.

Another amendment would allow commuters who qualify for the earned income tax credit to claim a refund on congestion pricing fees minus the cost they would have paid for a monthly, unlimited MetroCard. The revised bill would also exempt New Yorkers with handicap parking permits from paying congestion pricing fees.

A spokesman for the mayor, John Gallagher, said he expects the impact of the new exemptions for low-income and handicapped drivers on congestion pricing revenue to be “minimal.”

With many lawmakers still publicly on the fence, the mayor indicated that the changes to the bill could broaden its support. With an April 7 deadline to enact a congestion pricing program or lose $354 million in promised federal funds fast approaching, the City Council and state Legislature could vote on the new bill as early as today.

“The amendments that the Senate introduced last night to their bill will address many of the remaining concerns that we’ve been hearing from the City Council and members of the state Legislature,” Mr. Bloomberg said yesterday in a statement. “This bill is one everyone can stand behind and be proud of — most importantly because it will reduce traffic, cut pollution and raise billions of dollars to make badly needed improvements to our mass transit system.”

In addition to the legislative changes, Mr. Bloomberg has been working hard to persuade individual lawmakers to get behind his congestion pricing plan. According to one congestion pricing opponent, Council Member Lewis Fidler, Mr. Bloomberg met with another city legislator to offer fund-raising help in the 2009 elections in exchange for support on congestion pricing. Mr. Fidler said the council member came to him to say he turned the mayor down. Mr. Gallagher declined to comment on the allegation.

Speaker Christine Quinn, who is working to secure votes in the City Council for the mayor’s congestion pricing plan, praised the Senate yesterday for including the new amendments.

“New provisions for low-income and disabled commuters, and a more equitable fee and penalty structure are all steps in the right direction,” Ms. Quinn said in a statement. “It’s an additional good sign that New Jersey will have to pay its fair share.”

An opponent of the congestion pricing plan, Assemblyman Richard Brodsky of Westchester, derided the new amendments yesterday as “gimmicks.”

“The Mayor’s plan remains an unfair regressive tax on middle income people from the outer boroughs,” Mr. Brodsky said in a statement. He accused the mayor of striking “political bargains with special interests” by exempting from congestion fees private buses, whose trade organization, the American Bus Association, is represented by Senator D’Amato’s lobbying firm, Park Strategies.

Asked for comment, Mr. Gallagher denied that lobbying had anything to do with the bus exemption. “The Urban Partnership Agreement, which awarded New York City $354 million if we enact congestion pricing, requires that we exempt buses,” he said.