49 CFR § 571.102 - Standard No. 102; Transmission shift position sequence, starter interlock, and transmission braking effect.
S1. Purpose and scope. This standard specifies the requirements for the transmission shift position sequence, a starter interlock, and for a braking effect of automatic transmissions, to reduce the likelihood of shifting errors, to prevent starter engagement by the driver when the transmission is in any drive position, and to provide supplemental braking at speeds below 40 kilometers per hour (25 miles per hour).
S3.1 Automatic transmissions.
S3.1.1 Location of transmission shift positions on passenger cars. A neutral position shall be located between forward drive and reverse drive positions.
S184.108.40.206 Transmission shift levers. If a steering-column-mounted transmission shift lever is used, movement from neutral position to forward drive position shall be clockwise. If the transmission shift lever sequence includes a park position, it shall be located at the end, adjacent to the reverse drive position.
S3.1.2 Transmission braking effect. In vehicles having more than one forward transmission gear ratio, one forward drive position shall provide a greater degree of engine braking than the highest speed transmission ratio at vehicle speeds below 40 kilometers per hour (25 miles per hour).
S3.1.3 Starter interlock. Except as provided in S220.127.116.11 through S18.104.22.168, the engine starter shall be inoperative when the transmission shift position is in a forward or reverse drive position.
S22.214.171.124 After the driver has activated the vehicle's propulsion system:
(a) The engine may stop and restart automatically when the transmission shift position is in any forward drive gear;
(b) The engine may not automatically stop when the transmission is in reverse gear; and
(c) The engine may automatically restart in reverse gear only if the vehicle satisfies (1) and (2):
S126.96.36.199 Notwithstanding S188.8.131.52, the engine may stop and start at any time after the driver has activated the vehicle's propulsion system if the vehicle can meet the requirements specified in paragraphs (a) and (b):
(a) For passenger cars, multi-purpose passenger vehicles, trucks and buses with a GVWR less than or equal to 4,536 kg (10,000 pounds), the vehicle's propulsion system can propel the vehicle in the normal travel mode in all forward and reverse drive gears without the engine operating. For passenger cars, multipurpose passenger vehicles, trucks and buses with a GVWR greater than 4,536 kg (10,000 pounds), the vehicle's propulsion system can propel the vehicle in the normal travel mode in Reverse and at least one forward drive gear without the engine operating.
(b) If the engine automatically starts while the vehicle is traveling at a steady speed and steady accelerator control setting, the engine does not cause the vehicle to accelerate.
S184.108.40.206 If the transmission shift position is in Park, automatically stopping or restarting the engine shall not take the transmission out of Park.
S3.1.4 Identification of shift positions and of shift position sequence.
S220.127.116.11 Except as specified in S18.104.22.168, if the transmission shift position sequence includes a park position, identification of shift positions, including the positions in relation to each other and the position selected, shall be displayed in view of the driver whenever any of the following conditions exist:
(a) The ignition is in a position where the transmission can be shifted; or
(b) The transmission is not in park.
S22.214.171.124 Except as specified in S126.96.36.199, if the transmission shift position sequence does not include a park position, identification of shift positions, including the positions in relation to each other and the position selected, shall be displayed in view of the driver whenever the ignition is in a position in which the engine is capable of operation.
S188.8.131.52 Such information need not be displayed when the ignition is in a position that is used only to start the vehicle.
S184.108.40.206 All of the information required to be displayed by S220.127.116.11 or S18.104.22.168 shall be displayed in view of the driver in a single location. At the option of the manufacturer, redundant displays providing some or all of the information may be provided.
S3.2 Manual transmissions. Identification of the shift lever pattern of manual transmissions, except three forward speed manual transmissions having the standard “H” pattern, shall be displayed in view of the driver at all times when a driver is present in the driver's seating position.