Every time gas prices soar, Americans get a reminder of how dependent we are on oil. Case in point: the Shenandoah Valley, where Interstate 81 serves as a speedway for 18-wheelers, the truck stops are the size of small towns and even your basic crossroads gas station can have as many as 20 pumps.
A large percentage of the traffic on Interstate 81 is truck traffic. It's considered by both passenger-car drivers and truckers to be a somewhat dangerous stretch of highway. Michael S. Williamson/The Washington Post Buy Photo