A proposal to build a Cross Downtown Brooklyn Tunnel, an idea studied by the state in 2010, is sparking new interest. As the Brooklyn-Queens Expressway from Atlantic Avenue to Sands Street faces a massive, $3.4 billion reconstruction, a once-in-a-lifetime window of opportunity has opened, says longtime Cobble Hill community leader and graphic designer Roy Sloane. Sloane came up with the tunnel concept at a planning session in June 2010. Sloane, former president of the Cobble Hill Association, is the first to admit he is not an engineer. He was, however, a member of the original Brooklyn-Queens Expressway Advisory Committee and...