Following the passage of the Federal-Aid Highway Act of 1956 by Congress, the United States launched the largest highway construction program in history. Sometimes lost in this story is the fact that the individual state highway departments, as in past federal-aid programs, were the primary units of government actually responsible for designing these expensive, high-speed highways, which have had a profound impact on American society and culture. The federal government established standards for the system and solved the problem of how to pay for it with gas and other federal excise taxes locked away in the Highway Trust Fund. It was the states, though, that implemented the program and each state had its own starting point and proclivities in planning and building their highways and bridges. Construction of the entire system was to be staged out over 15 years.
The North Carolina State Highway Commission was in a good position to implement the interstate highway program, unlike some states that had no prior experience with highways of an interstate character. North Carolina's engineers had been building short segments of high-speed, limited-access highway since the late 1940s, mostly in the form of bypasses to carry major highways around towns and cities. The bypasses removed through traffic, especially trucks, from Main Street. The earliest and most noteworthy of these bypasses was the Lexington Bypass, built from 1949 to 1951, which even included North Carolina's first cloverleaf interchange. Many of the bypasses became parts of the original interstate highway routes, now designated in North Carolina as interstate business "green" routes. North Carolina, long known as the "Good Roads State," was characteristically among the early leaders in the development of interstate highways with a large percentage of its original interstate routes, including I-26 south of Asheville, I-40 west of Greenville, and I 85 and I 95 nearly completed by the mid-1960s.