North Carolina Highway System - History

History

The original highway numbering system for North Carolina was established in the 1920s. Major routes were multiples of 10, with 10, 20, and 90 running east/west, 30, 40, 50, 70, and 80 running north/south, and 60 running as a diagonal route. These cross-state routes were used as a basis for numbering the two-digit roads that served as the major city-city connectors. For example, NC 90 used to run along modern U.S. 64, which explains the multiple "90s" that branch off U.S. 64 today (NC 96, 97, and 98).

Three-digit numbered roads were less important spurs off the two-digit roads and often served as rural connectors. These were numbered in a scheme opposite of the U.S. and Interstate auxiliary routes; the spur routes received an extra "ones" digit instead of an extra "hundreds" digit. The first spur received the number "xx1" and the second received "xx2", where xx is the parent route number. This explains the predomination of such routes as 751, 191, 561, and the relatively few "xx0" routes (which would be the 10th assigned spur route ... few parent routes would have spurs numbered this high).

In 1933-34 many roads were renumbered to eliminate conflicts with the U.S. highways now crisscrossing the state. Some numbers (50, 90), which had become effectively U.S. routes (1 and 64 respectively) were moved or eliminated while others that conflicted with established U.S. route numbers in the state were changed to non-conflicting numbers. This seems to have been done without regard to the earlier numbering system, as were all future additions to the state highway system, which is where the modern "lack of any system" system came to be.

In 1937, several routes were renumbered to be contiguous with South Carolina routes, and in 1940 the same happened with Virginia. No effort has ever been made to match up with Tennessee or Georgia routes, but most cross-border numbered roads along this area are already U.S. highways anyway.

In the 1950s, routes that conflicted with Interstates were renumbered.

The most recent numbering change happened in 2002. Recently, NC 136 and NC 3 swapped numbers. This was to place NC 3 near Dale Earnhardt Sr.'s home of Kannapolis. The old NC 3/current NC 136 is a short spur in Currituck County. Currently, the only North Carolina highways in conflict with an Interstate number in the state are NC 73 and NC 540, the latter forming an extension of I-540.