Modern Marvels

Superhighways (15x4)

Air date: Feb 28, 2008

Millions of drivers travel the world's superhighways each year. See a multi-billion dollar expansion project in Houston where a stretch of superhighway is being widened to 20 lanes & Take a ride atop the High-Five, a 12-story, five-level interchange that's become the latest Dallas tourist attraction. Then it's off to China's 28,000-mile National Trunk Highway System.