On June 23, 2015, the National Highway Traffic Safety Administration (NHTSA) published in the Federal Register (Vol. 80, Number 120, Docket No. NHTSA-2015-0056) a Final Rule to add a new Federal Motor Vehicle Safety Standard (FMVSS) 136, Electronic Stability Control Systems (ESC) for Heavy Vehicles. ESC systems on truck tractors and certain large buses (Gross Vehicle Weight Rating [GVWR] of greater than 11,793 kilograms [26,000 pounds]) use engine torque control and computer-controlled braking of individual wheels to assist the driver in maintaining control of the vehicle and maintaining its heading in situations in which the vehicle is becoming roll unstable or experiencing loss of control. Intervention by the ESC system and its assistance in maintaining control of the vehicle can prevent fatalities and injuries associated with vehicle rollover or collision.
The effective date of this Final Rule is August 24, 2015. Applicable implementation dates are:
- New typical three-axle truck tractors manufactured on or after August 1, 2017.
- All other truck tractors manufactured on or after August 1, 2019.
- Buses over 14,969 kilograms (33,000 pounds) GVWR manufactured on or after 3 years of the date of the Final Rule.
- Buses greater than 11,793 kilograms (26,000 pounds) but not more than 14,969 kilograms (33,000 pounds) GVWR manufactured on or after 4 years of the date of the Final Rule.
Rulemaking leading to this Final Rule included a May 23, 2012 NPRM proposal requiring truck tractors and large buses with a GVWR of greater than 11,793 kg (26,000 lb.) to be equipped with stability enhancing technology and the July 6, 2012 Moving Ahead for Progress in the 21st Century Act (MAP-21) which incorporated Subtitle G, the Motorcoach Enhanced Safety Act of 2012. The Final Rule considered information from additional testing, evaluation and comments received at the July 24, 2012 public hearing and those submitted responding to the May 23, 2015 NPRM. Items in the Final Rule that differ from the NPRM include:
- ESC specified over Roll Stability Control (RSC).
- Alternative test maneuver (J-turn) to demonstrate ESC capability is acceptable.
- Sine with Dwell (SWD) maneuver to test both roll and yaw instability is not required.
- Requirements for some specific manufacturer documentation for NHTSA are removed.
- Lead times for implementation are revised.
- Potential retrofit requirement is removed.
- Various test parameters: steering controller will not be required for the J-turn test, specifying 30 degrees as the minimum articulation angle, control trailer specifications, test weight to be GVWR, ambient conditions, test surface, tires, mass estimation cycle, brake conditioning, reduced test instrumentation, etc. are revised.
- Disable ESC function not allowed.
- ESC malfunction telltale operation is specified; new telltale for type of vehicle is defined.
The NHTSA provided an analysis that estimates that this Final Rule will result in societal economic savings resulting from preventing crashes, reducing congestion, and preventing property damage such that the net cost of this Final Rule ranges from $3.6 to $12.3 million at a 3 percent discount rate and from $12.3 to $19.2 million at 7 percent discount rate.
Petitions for reconsideration of this Final Rule must be received by NHTSA by August 7, 2015.