A plan to charge drivers traveling into Manhattan's most congested neighborhoods during peak hours is getting support from Mayor Michael Bloomberg, who plans to give a detailed policy address tomorrow outlining strategies for combating climate change, traffic and a host of other long-term issues.Sources have said tomorrow's speech will include a formal endorsement of congestion pricing -- an approach to reducing traffic by charging drivers who enter areas of Manhattan with the heaviest congestion. The mayor's office would not confirm whether he indeed plans to undertake such a program.After speaking enthusiastically about it in his weekly radio address yesterday, Bloomberg said that if such a policy were instituted, it likely would not affect Staten Islanders.Bloomberg -- who often reminds people that despite his billionaire status, he rides the subway -- said drivers who already pay tolls on bridges and tunnels would not necessarily be hit twice with both full fees."It's successful in London. It's successful in Singapore," Bloomberg said, alluding to cities that employ congestion pricing. "We know a couple things. Traffic is [getting] worse, costs a lot of money, pollutes, makes it much more difficult to get to stores in Manhattan."Several Island politicians were not sold on the idea."My first reaction is it's bad for Staten Island," said City Councilman Michael McMahon (D-North Shore). "It's really just another fee that Staten Islanders would have to pay to get into that part of the city, and we're already so overcharged for every movement that we make." He also was not impressed with the idea of a discount for Islanders predicated on their taking the bridge.Bloomberg may try to appeal to outer-borough politicians with a promise to spend the revenue on transportation projects throughout the city, and one source said the mayor's administration has already offered a potential flow of cash for specific Island projects if congestion pricing comes to fruition."If you were to charge, you'd take that money and invest it in mass transit," Bloomberg said.City Councilman James Oddo said he did not want to reject the plan outright, but raised concerns because of the meager mass transit system on the Island. "We can't sustain the traffic levels we have and continue to be a productive city," Oddo (R-Mid-Island/Brooklyn) said, but quickly added, "You're going to ask a small-business owner who drives a van in to take a bus or a train, to a ferry, to a subway? Given the unfortunately unique situation Staten Islanders find themselves in, they have to consider us in a different light."Congestion pricing would ease traffic in parts of the Island cluttered by cars heading into Manhattan, argued Paul Steely White, executive director of Transportation Alternatives, a group backing the concept."If paired with parking reforms and walking improvements and biking improvements, it could really transform the city, drastically reduce carbon emissions and drastically improve the health and quality of life for New Yorkers," he said. "In order for New York to meet the challenges of growth and global warming, we have to switch auto trips to other ways of getting around -- and congestion pricing is the most efficient way to that."A congestion pricing proposal would have to be approved by the state. Jennifer Givner, a spokeswoman for Democratic Gov. Eliot Spitzer, said he "intends to closely examine the proposal."Mark Hansen, a spokesman for GOP Senate Majority Leader Joseph Bruno, said the senator had not "seen the details of the plan yet."Sisa Moyo, a spokeswoman for Democratic Assembly Speaker Sheldon Silver, said he is "looking forward to seeing the mayor's plan unveiled."Sources in both houses said it would be a tough sell, and likened it to the former commuter tax.Sally Goldenberg covers City Hall for the Advance and Rob Hart covers state government. They may be reached at goldenberg@siadvance.com and rhart@siadvance.com.