High Quality Content by WIKIPEDIA articles! In 1928, the U.S. state of Virginia renumbered many of its state highways. This renumbering was caused by a new law that greatly increased the state highway mileage. The old system, in which three-digit routes were spurs of two-digit routes, was unwieldy for a large number of routes, and so a new system, in which three-digit routes were assigned by district, was adopted.