Electronic Stability Control (ESC) is the generic term for systems designed to improve a vehicle's handling, particularly at the limits where the driver might lose control of the vehicle.
Robert Bosch GmbH were the first to deploy an ESC system, called Elektronisches StabilitÃ¤tsprogramm (ESPÂ®) that was used first by Mercedes-Benz and BMW in 1995. It was then introduced to the mass market by Continental Automotive Systems under the broader name of Electronic Stability Control, which is now the more common term recognized by the Society of Automotive Engineers, although individual motor manufactures use a range of different marketing names (see below).
ESC compares the driver's intended direction in steering and braking inputs, to the vehicle's response, via lateral acceleration, rotation (yaw) and individual wheel speeds. ESC then brakes individual front or rear wheels and/or reduces excess engine power as needed to help correct understeer (plowing) or oversteer (fishtailing). ESC also integrates all-speed traction control, which senses drive-wheel slip under acceleration and individually brakes the slipping wheel or wheels, and/or reduces excess engine power, until control is regained. ESC cannot override a car's physical limits. If a driver pushes the possibilities of the car's chassis and ESC too far, ESC cannot prevent a crash. It is a tool to help the driver maintain control.
ESC combines anti-lock brakes, traction control and yaw control (yaw is spin around a vertical axis). To grasp how it works, think of steering a canoe. If you want the canoe to turn or rotate to the right, you plant the paddle in the water on the right to provide a braking moment on the right side. The canoe pivots or rotates to the right. ESC fundamentally does the same to assist the driver.
Numerous international studies have confirmed the effectiveness of ESC in helping the driver maintain control of the car, help save lives and reduce the severity of crashes. In the fall of 2004 in the U.S., the National Highway and Traffic Safety Administration confirmed the international studies, releasing results of a field study in the U.S. of ESC effectiveness. NHTSA concluded that ESC reduces crashes by 35%. The prestigious Insurance Institute for Highway Safety (IIHS) later issued their own study that concluded the widespread application of ESC could save 7,000 lives a year. In June 2006, the IIHS updated the results of their 2004 study by stating that up to 10,000 fatal crashes could be avoided annually if all vehicles were equipped with ESC. ( pr061306.html) That makes ESC the greatest safety equipment development since seat belts, according to some experts. However, some people contend (backed up by the theory of risk compensation) that the perception of safety conferred by the ESC will encourage more dangerous driving, as seems to be the case with seat belts.
Some driving enthusiasts, most publicly motoring journalists from enthusiast magazines, object to some of the implementations of ESC. They contend that by making it impossible to explore the dynamic behaviour of their cars, overzealous ESC systems spoil much of the fun of driving. Consequently, some manufacturers allow drivers to disable ESC systems, and/or use ESP systems that allow greater levels of under or oversteer before it intervenes. Some even provide a setting so the user can choose whether the system will intervene earlier or later stage. Enthusiasts have also begun to modify ESC systems to suit their preferred driving styles ( article.html) .
It has also been argued that ESC is being used as a "catch all" for poorly designed cars, whereby the basic mechanical handling of a car is unstable and ESC is used to fix the problem.
Another point of critique is that in the case of very dangerous drivers, the car will be able to be pushed further (and faster) before the limits of the vehicle and ESC are reached, meaning that should the vehicle become "out of control" this will happen at higher speeds, leading to more severe crashes.
Vehicle manufacturers use electronic stability control systems under different marketing names:
- Acura: Vehicle Stability Assist (VSA)
- Alfa Romeo: Vehicle Dynamic Control (VDC)
- Audi: ESP - Electronic Stabilization Program
- Buick: StabiliTrak
- BMW: Dynamic Stability Control (DSC), including Dynamic Traction Control
- Cadillac: All-Speed Traction Control & StabiliTrak
- Chevrolet: StabiliTrak (except Corvette - Active Handling)
- Chrysler: Electronic Stability Program (ESP)
- Dodge: Electronic Stability Program (ESP)
- DaimlerChrysler: Electronic Stability Program (ESP)
- Fiat: Electronic Stability Program (ESP) and Vehicle Dynamic Control (VDC)
- Ferrari: Controllo Stabilita (CST)
- Ford: AdvanceTrac and Interactive Vehicle Dynamics (IVD)
- GM: StabiliTrak
- Hyundai: Electronic Stability Program
- Honda: Electronic Stability Control (ESC) and Vehicle Stability Assist (VSA) and Electronic Stability Program (ESP)
- Holden: Electronic Stability Program (ESP)
- Infiniti: Vehicle Dynamic Control (VDC)
- Jaguar: Dynamic Stability Control (DSC)
- Jeep: Electronic Stability Program (ESP)
- Kia: Electronic Stability Program (ESP)
- Land Rover: Dynamic Stability Control (DSC)
- Lexus: Vehicle Dynamics Integrated Management (VDIM) with Vehicle Stability Control (VSC) and Traction Control (TRAC) systems
- Lincoln: AdvanceTrak
- Maserati: Maserati Stability Program (MSP)
- Mazda: Dynamic Stability Control
- Mercedes: Electronic Stability Program (ESP)
- Mercury: AdvanceTrak
- MINI Cooper: Dynamic Stability Control
- Mitsubishi: Active Skid and Traction Control MULTIMODE
- Nissan: Vehicle Dynamic Control (VDC)
- Oldsmobile: Precision Control System (PCS)
- Opel: Electronic Stability Program (ESP)
- Peugeot: Electronic Stability Program (ESP)
- Pontiac: StabiliTrak
- Porsche: Porsche Stability Management (PSM)
- Renault: Electronic Stability Program (ESP)
- Rover: Dynamic Stability Control (DSC)
- Saab: Electronic Stability Program
- Saturn: StabiliTrak
- SEAT: Electronic Stability Program (ESP)
- Å koda: Electronic Stability Program (ESP)
- Subaru: Vehicle Dynamics Control Systems (VDCS)
- Suzuki: Electronic Stability Program (ESP)
- Toyota: Vehicle Dynamics Integrated Management (VDIM) with Vehicle Stability Control (VSC)
- Vauxhall: Electronic Stability Program (ESP)
- Volvo: Dynamic Stability and Traction Control (DSTC)
- VW: Electronic Stability Program (ESP)
Electronic Stability Control forms the foundation for new advances on vehicle equipment that will save additional lives and give the driver still more control over the vehicle. The computing power of ESC facilitates the networking of active and passive safety systems on the car, creating the opportunity to address still more causes of crashes.
In the US, the NHTSA is currently evaluating whether ESC should be mandatory on all passenger vehicles, due to the effectiveness noted above.