Traction Control (TC) Technology

Traction Control

Traction control is a technology designed to help your vehicle maintain traction, no matter how slippery the road surface. Technically, it is a mechanical, hydraulic, or electric system that maintains or controls traction to any wheels driven by the engine. Unlike mechanical traction control systems of the past (such as limited slip differentials), today’s systems are nearly all computer-controlled as they actively watch wheel slip. An option formerly reserved for performance or specialty vehicles, you can find traction control on all types of vehicles today.

Microcomputers solve the traction equation

Traction has always been the Achilles Heel of any vehicle. A perfectly capable car or truck becomes completely useless when stuck in sand, mud, or snow. Early in the development of the modern motor vehicle, engineers realized that 4-wheel drive (4WD) was one answer. By sending engine power to all four wheels, at least one wheel would have enough grip to pull the vehicle through. It was a brilliant discovery, but 4WD meant that the vehicle would have to carry extra weight, complexity, and suffer the increased fuel consumption associated with the 4WD drivetrain, even when it was not in use. One hundred years after the development of the automobile, microcomputer technology has finally solved the traction conundrum.

An anti-lock brake system, but in reverse

Nearly every automotive traction control system uses a form of technology designed for aircraft in the 1950s called anti-lock brakes, or ABS. Aircraft engineers developed a system of mechanical sensors to measure and detect when a wheel was skidding and hydraulically release the braking force on that wheel. With an ABS system, an aircraft could brake with maximum stopping power without skidding, regardless of weather conditions. With further development, automotive engineers realized they could “reverse” the operation of the ABS to build an effective traction control system using the same sensors.

Traction control works by monitoring the rotation of each wheel independently. The ABS control unit “understands” that all wheels should be rotating at basically the same speed (unless the vehicle is turning). If one wheel begins to rotate quicker, indicating a loss of traction, the system instantly recognizes the loss of traction and takes action. In the blink of an eye, the throttle is reduced and/or braking force is applied to the spinning wheel. In some vehicles, the electronic stability control system, which incorporates traction control technology, can actually steer the front wheels to avoid a spin.

As an added benefit, the braking on the spinning wheel transfers power to the opposite wheel through the differential, a gear system that allows the tires to rotate at different speeds through corners. Quite often, the opposite wheel has traction and the vehicle continues to move forward. With traction control, engine power can be altered between wheels, as needed, until the vehicle is no longer in need of traction assistance.

Do you need traction control?

As an active safety feature, traction control can help you avoid an accident as it prevents the vehicle from spinning its tires under acceleration or on low-traction surfaces. This could be very useful on a rainy day when crossing a busy highway, or when merging into traffic.

As a driver’s aid, traction control can help get you through an unexpected snowstorm or a sudden summer rain on a muddy road. In extreme circumstances such as an emergency maneuver, the system can help you avoid hitting another vehicle that suddenly cuts in front of you or can save you from an accident when avoiding debris in the road. Although it is very effective in nearly all circumstances, traction control cannot change the laws of physics, meaning that loss of traction may still cause an accident, even with this technology. Be sure to always be aware of road and traffic conditions, and make sure you avoid any tendency to drive faster because of the “safety net” the traction control system may provide.

As they share technology, traction control is nearly always bundled with an ABS braking system. Though you may not use them very often, in an emergency, the reassurance of these two active safety features is incomparable.