Back in January, 2001, the leading tunnel-building expert in the world, Dr. Martin Herrenknecht, told Newsday it was technologically feasible — and, economically do-able — to build a tunnel under the Long Island Sound connecting Long Island to Westchester. “A tunnel in the Long Island Sound is not science fiction,” Herrenknecht said then in a phone interview from his home in Hamburg, Germany. “This is absolute reality.” Herrenknecht knew. He had designed and engineered state-of-the-art tunnel boring machines being used at the time to build the 6-kilometer-long Westerschelde tunnel 200 feet under Antwerpe Harbor in the Netherlands and had been enlisted to assess the feasibility of replacing the Tappan Zee Bridge with a tunnel -- as well as with the possibility of building one under the Sound between Syosset and Rye -- by a retired engineer named Alexander Saunders. Saunders, of Tarrytown, had stumbled upon the Westerschelde tunnel project while on vacation, giving him the brainstorm. But while Herenknecht said the Sound project could be done at “a fraction of the cost” of the long-ago proposed bridge across the Sound, the idea fell upon the deaf ears of politicians in New York. As Lee Koppelman, the then long-time executive director of the Long Island Regional Planning Board, said that January: “It’s not a pie-in-the-sky idea . . . The question is: Is it politically feasible? Don’t leave that word out. That's the only application of feasible that matters here on Long Island." Six years later, an investment group headed by Garden City developer Vince Polimeni has revived the idea with a privatized plan to build a 16-mile-long tunnel between the end of the Seaford-Oyster Bay Expressway in Syosset to the Interstate-95 and Interstate-287 interchange in Rye. We need it. It would be good for Long Island and a tremendous benefit for Long Island drivers. But, will it happen? Who knows? The cost to build this tunnel, in today’s dollars, would be about $10 billion, Polimeni said. But the cost to taxpayers would be — and, you’ll like this — nothing. Nada. Zero. Involved in the consortium to build the proposed “Cross Sound Link Tunnel” are the engineering firm Hatch Mott MacDonald, which is a world-leader in tunnel-building, as well as financial market analysts Bear, Stearns & Co. Inc. and former Suffolk County Executive Patrick Halpin. They believe that by 2025 the tunnel could be moving 80,000 vehicles per day between Westchester and Long Island, turning a 45-mile trip into a 16-mile trip, cutting down on pollutants and traffic congestion and wear-and-tear on public roads. They see this for an average toll fare somewhere in the neighborhood of $25. The technology, of course, is there. Is the will? Halpin, a former Democratic big-wig on the local political stage, said Tuesday in a conversation with Newsday that he believes that will is there. And will be. And considering that the leaders of both counties, as well as the state, are now Dems -- we'll, Halpin certainly seems like the right guy to get them on board. Polimeni, too, believes that since the project would be built with private funding and not public taxpayer monies, politcal support will follow. There is, however, a potential stumbling block. It is a big one. That is the potential battle to be waged by property owners, a large percentage of them wealthy, on both the north shore of Long Island — and in Rye. Though any tunnel would be built about 150 feet below residential and private properties, there is a question of how it could potentially de-value land. Theoretically, the state government could argue eminent domain — and force the project on landowners. More realistically, Polimeni said Tuesday, is that the consortium would attempt to work out lease deals with owners. He believes that is feasible, pointing to correlaries with current under-Manhattan tunnel projects such as the Long Island Rail Road’s East Side Access and the Second Avenue Subway. Though potential state toll revenues could be affected by a reduction in traffic volume on Metropolitan Transportation Authority Bridges and Tunnels, chances are offsets would have to be negotiated into any lease with the consortium regarding revenues generated by the Cross Sound Link. We're not in love with the idea of privatizing roads -- or bridges and tunnels, for that matter. In fact, many times it's a bad idea since it allows a private company to mandate public access to public space. But, this would be unlike other privatization projects around the country — i.e., the Chicago Skyway, which earlier this decade was privatized in a 99-year lease agreement — because other privatized roads were built with public taxpayer dollars and then turned over to private companies. This tunnel would be built with private funds and operated with private funds and potentially would generate public funds to ease the tax burden. And if drivers chose not to use it, there remains other access via pubically-owned and operated bridges and tunnels. Right now, the project remains in the earliest proposal stages. But, members of the consortium claim the initial reaction among New York State Department of Transportation officials, as well as politicians, has been positive. And they believe the project will more forward. We can only hope that is the case. Because, we need it. But remember: The original proposal for a Long Island Sound Bridge is closing in on its 50th Anniversary. And it was never anything more than a pipe dream. Any proposed Cross Sound Tunnel will suffer the same fate — until, that is, officials in New York have the political will to make it reality.