According to Insurance Institute for Highway Safety and the U.S. National Highway Traffic Safety Administration, one-third of fatal accidents could be prevented by the use of this technology.
Electronic stability control (ESC), also referred to as electronic stability program (ESP) or dynamic stability control (DSC), is a computerized technology that improves a vehicle’s stability by detecting and reducing loss of traction (skidding).
ESC intervenes only when it detects a probable loss of steering control, i.e. when the vehicle is not going where the driver is steering. This may happen, for example, when skidding during emergency evasive swerves, under steer or over steer during poorly judged turns on slippery roads, or hydroplaning. ESC may also intervene in an unwanted way during high-performance driving, because steering input may not always be directly indicate the intended direction of travel (i.e. controlled drifting). ESC estimates the direction of the skid, and then applies the brakes to individual wheels asymmetrically, opposing the skid and bringing the vehicle back in line with the driver’s intended direction. When ESC detects loss of steering control, it automatically applies the brakes to help “steer” the vehicle where the driver intends to go. Braking is automatically applied to wheels individually. Some ESC systems also reduce engine power until control is regained. Additionally, the system may reduce engine power or operate the transmission to slow the vehicle down. ESC does not improve a vehicle’s performance; instead, it helps to minimize the loss of control.
ESC can work on any surface, from dry pavement to frozen lakes. It reacts to and corrects skidding much faster and more effectively than the typical human driver, often before the driver is even aware of any expected loss of control. In fact, this led to some concern that ESC could allow drivers to become overconfident in their vehicle’s handling and/or their own driving skills. For this reason, ESC systems typically inform the driver when they intervene, so that the driver knows that the vehicle’s handling limits have been approached. Most activate a dashboard indicator light and/or alert tone; some intentionally allow the vehicle’s corrected course to deviate very slightly from the driver-commanded direction, even if it is possible to more precisely match it.
All ESC manufacturers emphasize that the system is not a performance enhancement nor a replacement for safe driving practices, but rather a safety technology to assist the driver in recovering from dangerous situations. ESC does not increase traction, ESC works within inherent limits of the vehicle’s handling and available traction between the tyres and road. A reckless maneuver can still exceed these limits, resulting in loss of control. Drive Safe!