About: 1964 state highway renumbering (California)

In 1963 and 1964, the California Division of Highways implemented a major renumbering of its state highways. The majority of sign routes—those marked for the public—kept their numbers; the main changes were to the legislative routes, which had their numbers changed to match the sign routes. Many formerly unsigned routes received sign numbers corresponding to their new legislative numbers. A smaller change was the removal and truncating of many U.S. Routes in favor of the Interstate Highways (designated in 1959), and the renumbering of State Routes that conflicted with Interstate numbers. Some U.S. Routes that were officially removed continued to be signed until the replacement Interstates were completed.