Following World War II the United States embarked on an aggressive development program that by 2004 resulted in construction of 46,837 miles of interstate highways. In 2006 this federal highway system supported the movement of 10.7 billion tons of freight, which equaled 69 percent of all freight moved in the United States. However, by 2008 this highway system was in need of expansion and widespread repair to sustain the safe movement of over 26 million trucks