AUSTIN - In what sounds like another tall tale told by a Texan, the Lone Star State has embarked on an audacious project to build superhighways so big, so complex, that they will make ordinary interstates look like cow paths. The Trans-Texas Corridor project, as envisioned by Republican Gov. Rick Perry in 2002, would be a 4,000-mile transportation network costing $175 billion over 50 years, financed mostly if not entirely with private money. The builders would charge motorists tolls. But these would not be mere highways. They would be megahighways -- corridors up to a quarter-mile across, consisting of as...