High Quality Content by WIKIPEDIA articles! In 1933, the U.S. state of Virginia renumbered almost all of its state highways. This renumbering was caused by the assignment of numbers from 600 up to the new secondary system, but all three-digit numbers were affected. At the same time, all numbers that conflicted with U.S. Routes - except State Route 13 - were renumbered, and all long overlaps with U.S. Routes were eliminated. Several new routes had the same numbers as U.S. Routes and served as their extensions.