The number of vehicles available with electronic stability control (ESC) systems has increased significantly over the past 10 years, but the fitment of electronic stability control systems will become even more widespread following the issue of two recent regulations by the United Nations Economic Commission for Europe (UN ECE) which will mandate their fitment to virtually all types of motor vehicle and some types of trailer. In the past month, the UN ECE have issued a new Global Technical Regulation (GTR) on ESC systems for light vehicles (GTR No. 8) and an amendment to the ECE Regulation No. 13 to mandate the fitment of ESC systems to heavy vehicles and heavy trailers.
ESC systems are electronic systems, usually integrated with the vehicle’s anti-lock braking system, that are designed to help the driver maintain control of the vehicle during extreme cornering manoeuvres, such as those initiated to avoid a potential crash situation. The ESC system uses sensors to monitor the driver’s intended heading (i.e. steering input) and compare it with the vehicle’s actual response. If the vehicle’s response does not match the driver’s intention, the ESC will apply uneven braking at individual wheels on the vehicle to assist the vehicle in achieving the intended course, thereby avoiding potentially catastrophic oversteer or understeer situations.
Numerous studies into real world accident statistics for vehicles fitted with ESC have shown that ESC equipped vehicles have significantly lower accident rates than equivalent non-ESC equipped vehicles, which has led legislators around the world to consider implementing requirements for the mandatory fitment of such systems. The first legislative authority to mandate the fitment of ESC systems was the US National Highway Traffic Safety Administration (NHTSA), which will mandate the fitment of ESC systems to passenger cars, multipurpose passenger vehicles, light trucks and buses with a GVW up to 4536 kg via Federal Motor Vehicle Safety Standard (FMVSS) No. 126, the phase-in requirements for which begin from 1st September 2008.
Newly published Global Technical Regulation No. 8 covers ESC systems for passenger cars, multipurpose passenger vehicles, light trucks and buses with a GVW up to 4536 kg. Its requirements are based on those of FMVSS 126 and include both functional and performance requirements.
It is expected that the NHTSA will propose amendments to FMVSS 126 to align its requirements with those of GTR No. 8 in the near future and a proposal to introduce identical requirements to those of GTR No. 8 into ECE 13H have already been proposed.
The 11th series of amendments to ECE Regulation No. 13 (ECE 13.11) introduce requirements for ESC systems, referred to as a "vehicle stability function" in the Regulation, for buses and coaches with more than 9 seats, trucks with a GVW greater than 3500 kg and trailers with a GVW greater than 3500 kg. The Regulation contains requirements for both "directional control" and "roll-over control" functions and includes a phased introduction for the mandatory fitment of ESC systems by vehicle type, with introduction dates ranging from 11th July 2009 to 11th July 2016.