This SAE Recommended Practice applies to speedometers, odometers, and speedometer drives typical of passenger vehicles, buses, and trucks used for personal or commercial purposes. The method of determining wheel revolutions per unit distance and overall system design variation are applicable to passenger cars only. Comparable recommendations for trucks and buses are under development. The data of tachometers is applicable to vehicular use, as previously described, and also to stationary and marine engines and special vehicles.
This document covers technology and products which are mature and are either not likely to change in the foreseeable future or are no longer applicable. The development of a new standard is underway.