The Tappan Zee Bridge, the most critical transportation link across the Hudson River north of New York City, is not even half as old as the Brooklyn Bridge, but its warranty has already expired. Started on the cheap during the Korean War, the Tappan Zee was deliberately built to last just 50 years. It passed that milestone last month, just days after transportation planners began gathering public advice about how to fix or replace it. But the decaying, overburdened span's anniversary was more bitter than sweet. Little love has been lost between the Tappan Zee and the tens of thousands...