7. Tokyo Metropolitan Expressway

The Tokyo Metropolitan Expressway is the capital city's most important road system. Begun 50 years ago, with a 4.5-kilometer stretch built for the 1964 Olympics, it is today a massive, complex web of roads that runs more than 300 kilometers and carries more than 1 million vehicles per day. Our guest this time is Kenichi Kawabe, an expert on transportation systems and the technology used to build them. And in Plus One, navigating the expressway like a pro!