Worldwide, there are many regulations and standards for the installation of lighting and signaling devices on road vehicles. Differences in engineering and human-factors philosophy, compliance systems, industry practice, and other factors mean the specifications for any given functions or device differ by issuing body, but all the standards have the same general intent. That is to ensure the driver can see safely in darkness or inclement weather without causing blinding glare to other drivers, and that the vehicle is adequately conspicuous with regard to its presence, position, size, direction of travel, and driver's intent to decelerate or change directions.
There are windows of overlap among the various standards for installation of each particular lighting device or function, created by cooperative effort among the various standards-issuing bodies. There are also windows of overlap among the various standards for design, construction, and performance of each particular lighting device or function, but those aspects are outside the scope of this document. The purpose of this SAE Recommended Practice is to describe the overlapped common specifications for installation of each device and function so that vehicle manufacturers can minimize the proliferation of vehicle configuration variants and associated costs. This document is intended as an international industry guide to lighting and light signaling device installation. Manufacturers installing lighting and signaling devices in accordance with this SAE Recommended Practice will maximize their ability to equip any given vehicle model with one lighting system configuration acceptable for sale in the greatest possible number of markets.