Page:Manual on Uniform Traffic Control Devices for Streets and Highways, 1961 Edition.pdf/18



Traffic control devices are all signs, signals, markings, and devices placed on or adjacent to a street or highway by authority of a public body or official having jurisdiction to regulate, warn, or guide traffic.

Modern highways and vehicles operating thereon, together with changes in our way of life, have resulted in ever-increasing ranges of travel to the end that highway users have come to depend on traffic control devices for information, warning, and guidance. So great is this dependence that uniform, high-quality devices are necessary to productive use and public acceptance of any highway regardless of its excellence in width, alinement, and structural design.

The need for high uniform standards was recognized long ago. The American Association of State Highway Officials (AASHO) published a manual for rural highways in 1927 and the National Conference on Street and Highway Safety published a manual for urban streets in 1929. But the necessity for unification of the standards applicable to different road and street systems was obvious. To meet this need, a joint committee of the American Association of State Highway Officials and the National Conference on Street and Highway Safety developed and published in 1935 the original edition of this Manual on Uniform Traffic Control Devices. That committee, though changed from time to time in organization and personnel, has been in continuous existence and has been responsible for periodic revisions of the Manual, including this 1960 edition.

Membership on the National Joint Committee on Uniform Traffic Control Devices has changed considerably during the years. The Institute of Traffic Engineers joined the Committee in 1942 and the National Committee on Uniform Traffic Laws and Ordinances replaced the National Conference on Street and Highway Safety in 1948. In 1960 the Committee was reorganized to include members from the National Association of County Officials (NACO) and the American Municipal Association (AMA). Currently the latter two associations each appoint two chief administrative officers as representatives. The American Association of State Highway Officials appoints seven members, two of whom are chief administrative officers. The Institute of Traffic Engineers appoints seven members (usually city traffic engineers), 1