The passage of the Federal Aid Highway Act of 1956 launched the largest highway construction program in history. Sometimes lost in this story is the fact that individual state highway departments were the primary units responsible for designing these expensive, high-speed highways, which had a profound impact on American society and culture.
The federal government established standards for interstate highways and solved the problem of how to pay for them with gas and other federal excise taxes locked away in the Highway Trust Fund. It was the states, though, that implemented the program. Each state had its own starting point and proclivities in planning and building highways and bridges. Construction of the entire system was staged out over 15 years.
The North Carolina State Highway Commission was in a good position to implement the program, unlike 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 was the Lexington Bypass, built from 1949 to 1951, which even included the state's first cloverleaf interchange. Many of the bypasses became parts of the original interstate highway routes, now designated 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 routes, including I-26 south of Asheville, I-40 west of Greenville, and I-85 and I-95 nearly completed by the mid-1960s.