"Simply rebuilding the highway in place would continue a great urban mistake," Fisher told the Staten Island Advance. "This is going to be New York City's biggest land use decision in years," RPA's Al Appleton said. "We can have just another road or a road that's urban-friendly."

The NY State DOT says it's examining a tunnel option in its environmental impact statement for the Gowanus, but it has generally poured cold water on the idea in public statements, citing cost and feasibility.

Fisher said if the state can afford a $4 billion plan for a Tappan Zee Bridge replacement and low ridership Tappan Zee commuter rail line, it should be willing to pay for the benefits a Gowanus tunnel would confer on Brooklyn. He said the Gowanus carries twice the daily traffic of the Tappan Zee.

The State DOT's plan to rebuild the Gowanus in place - while diverting thousands of cars each day onto local streets - has been a lightning rod since the early 1990s. When the DOT tried to begin the project without any environmental review, Brooklyn elected officials and community groups handed DOT its own head. DOT has been back at the drawing board now for a number of years, but is still in the midst of a lawsuit over the project's planning process.