Traction Control (TC) systems, on current production vehicles, are typically (but not necessarily) electro-hydraulic systems designed to prevent loss of traction (and therefore the control of the vehicle) when excessive throttle or steering is applied by the driver. Although similar to the Electronic Stability Control systems, the Traction Control systems don't have the same goal as them.
On road cars, TC is often packaged with Anti-lock Brakes (ABS), because the same sensors that detect wheels stopped or decelerating faster than other wheels also detects them spinning faster than other wheels or accelerating faster than a preprogrammed amount.
The intervention can consist of any, or all, of the following:
- Retard or suppress the spark to one or more cylinders
- Reduce fuel supply to one or more cylinders
- Brake one or more wheels
- Close the throttle, if the vehicle is fitted with drive by wire throttle.
The brake actuator, and the wheel speed sensors, are the same as that used for anti-lock braking systems.
Use of Traction Control
- In road cars: Traction Control is used mainly as a safety feature in high-performance cars, which would otherwise need very sensitive throttle input to keep them from spinning when accelerating, especially in wet or snowy conditions. It is also used in off-road vehicles to enhance traction on loose surfaces.
- In race cars: Traction Control is used as a performance enhancement, allowing maximum traction under acceleration without wheel spin. When accelerating out of turn, it keeps the tyres at the optimum slip angle.
It is widely thought that TC removes some skill and control from the driver. As such it is unpopular with many motor-sports fans. Some motor-sports series have given up trying to outlaw TC. With current state of technology, it is possible to implement TC as a part of software in ECU, and as such it is very hard to detect. In Formula One, an effort to ban TC has lead to the change of rules for 2008: every car must have a standard ECU, issued by FIA, which is relatively basic and does not have TC capabilities.