This SAE Recommended Practice establishes a uniform procedure for assuring the manufactured quality, provision for proper installation, and service performance of certain automotive products, specifically, the relocation, alteration, replacement and/or extension of secondary controls and systems. These include the following: Cruise Control; Door Locks; Gear Selector; Hazard Flasher; Headlight Beam Selector; Heater/Vent/Air Conditioner (HVAC); Horn; Ignition/Starter; Light controls; Mirrors; Parking Brake; Power Seats; Rear Accessories (Defogger, Wiper/Washer); Turn Signals; Window Regulators; and Windshield Wiper/Washer. The purpose of any Secondary control adaptation is to provide the effective use of the motor vehicle operating systems to a driver with a disability, so that he or she may drive and operate that motor vehicle with the same degree of safety as a driver who does not have a disability. Thus, the adaptive equipment must be (1) accessible to the driver with a disability for whom it is designed, (2) not susceptible to inadvertent operation which may be inconvenient or dangerous for the driver and other users of the highway transportation system, and (3) suitable for use by other drivers who may have a need to operate the motor vehicle. For purpose of this document, the secondary controls listed previously have been classified according to the following protocols. The categorization of these controls, while different from other SAE publications, is reflective of the manner in which driver rehabilitation specialists determine appropriate vehicle modifications. These categories are arranged to assign priorities that allow the user to operate a vehicle in the most efficient manner possible within the highway transportation system.

1. Mode A—These controls shall be operable by the driver while the vehicle is in operating mode. They must be accessible to the driver for which they were intended while being able to maintain control of the vehicle steering, brake and accelerator functions. Included in this group are: Cruise control “Set;” Headlight Beam Selector; Horn; Turn Signals; and, Windshield Washer/Momentary Wipe.
2. Mode B—These controls shall be operable by the driver while maintaining control of the vehicle brake function with the vehicle not in motion, as in the case of vehicle start-up or re-start necessitated by engine stall. Included in this group are: Gear Selector and Ignition/Starter.
3. Mode C—These controls shall be at least operable by the driver when the vehicle is stationary, either temporarily or parked. Included in this group are: Cruise control “On” and “Off;” Door Locks; Hazard Flashers; Heater/Vent/Air Conditioner (HVAC); Light Controls; Mirrors; Parking Brake; Power Seats; Rear Accessories (Defogger, Wiper/Washer); Windshield Wiper; and Window Regulator.