On Saturday, NewsHour Weekend examines how Sunbelt and Western cities that have grown along with their highways into sprawling metropolitan areas are increasingly turning to mass transit. Dallas has built the longest light-rail system in the country, which stretches far into its suburbs and has spurred billions of dollars of development. A couple hundred miles away, the city of Houston has a much shorter light rail system that is clustered in the city's center. But can these two car-centric cities learn to embrace mass transit - and the development that comes with it - and leave their cars at home? Special Correspondent Karla Murthy reports from Texas.