The purpose of this SAE Recommended Practice is to provide a series of engineering guidelines for the design of an automatic vehicle speed control, and to define the minimum control performance which a device must provide in order to be classified an automatic vehicle speed control. An automatic vehicle speed control is a device capable of maintaining selected vehicle speeds in the presence of changing road load conditions. This SAE Recommended Practice is intended to apply only to the design of an automatic vehicle speed control. It is not intended to encourage or discourage the installation of automatic vehicle speed controls on any class of vehicles, nor is it intended to influence the requirements of engine speed governors.