Traction Control Systems Explained

By: the Editors of Publications International, Ltd.  | 
A diagram of a traction control system. 
Image Gallery: Trucks Traction control systems limit power to the drive wheels to prevent wheel spin under acceleration. See pictures of trucks.
photo courtesy of Chevrolet

Traction is essential, but alignment and new tires can only do so much. To navigate adverse road conditions, a vehicle needs more help. That's where traction control systems (TCS) come in.

This sophisticated technology helps prevent the wheels from slipping during acceleration by ensuring that the driver maintains control over the vehicle. But there's more to it than that, which we'll explore in greater detail below.


What Is Traction Control?

Traction control is an electronic system that helps limit tire slip in acceleration on slippery surfaces [source: Morris]. In the past, drivers had to feather the gas pedal to prevent the drive wheels from spinning wildly on slippery pavement. Many of today's vehicles employ electronic controls to limit power delivery for the driver, eliminating wheel slip and helping the driver accelerate under control.

The primary objective of traction control is to maintain vehicle stability and steering during acceleration by minimizing wheel slop. Powerful rear-drive cars from the sixties often had a primitive form of traction control called a limited slip rear differential. Sometimes referred to as Positraction, a limited-slip rear axle will mechanically transfer power to the rear wheel with the most traction, helping to reduce, but not eliminate wheel spin.


While limited-slip rear axles are still in use in many front- and rear-drive vehicles today, the device can't completely eliminate wheel slip. Hence, a more advanced system was needed.

How Modern Traction Control Systems Work

In modern vehicles, traction-control systems utilize the same wheel-speed sensors employed by the antilock braking system. These sensors measure differences in rotational speed to determine if the wheels that are receiving power have lost traction [source: Markus].

When the traction-control system determines that one wheel is spinning more quickly than the others, it automatically "pumps" the brake to the spinning wheel to reduce its speed and lessen wheel slip.


In most cases, individual wheel braking is enough to control wheel slip. However, some traction-control systems also reduce engine power to the slipping wheels. On a few of these vehicles, drivers may sense pulsations of the gas pedal when the system is limiting power much like a brake pedal pulsates when the antilock braking system is working.

Many people mistakenly believe that traction control will prevent their vehicle from getting stuck in the snow. This couldn't be further from the truth. Traction control does not have the ability to increase traction; it just attempts to prevent a vehicle's wheels from spinning. For drivers who routinely drive in snowy and icy conditions, traction control, antilock brakes, and snow tires are must-have safety features.


Traction Control vs. Stability Control vs. ABS

While traction control focuses on prevents a single spinning wheel during acceleration, it is often confused with similar systems like electronic stability control (ESC) and anti-lock braking systems (ABS).

An anti-lock braking system uses ABS sensors to prevent the wheels from locking up during braking, ensuring that the driver maintains steering control [source: Wagner]. While ESC helps correct oversteer or understeer by applying brakes to individual wheels and reducing enging power to help steer the vehicle.


Though all three of these systems often work together to improve vehicle safety, it's important to understand that each has a distinct role, and serves different purpose.

The Impact of Traction Control on Driving

Traction control has significantly impacted driving, particularly in terms of safety and vehicle performance. It has become a standard feature in most new vehicles, reflecting its importance in modern automotive design.

However, it is essential for drivers to understand that while traction control can provide assistance in challenging conditions, it does not replace the need for careful and attentive driving. Knowing when the system is active and how it affects the vehicle's behaviour is crucial for maximizing its benefits.


Always In Control

Traction control has come a long way since its inception, evolving from a basic safety feature to a sophisticated system that enhances both performance and fuel efficiency. As vehicles evolve, the integration of traction control with other technological advancements promises to make driving safer, more efficient, and more enjoyable.

More importantly, by understanding how it works and its advantages, drivers can better appreciate the technology behind the wheel and make informed decisions about their driving practices, especially in adverse conditions.


Traction Control FAQ

Should I drive with traction control on or off?
Traction control should be turned on while driving. Regardless of your driving skills, the system is in place to prevent accidents and should not be turned off.
When should I turn off traction control?
Seeing as traction control is used to prevent vehicles from skidding, it is an important safety feature. It needs to be turned off, however, when the car is stuck in snow or mud and not able to move.
How do I turn my traction control back on?
This can be done by pressing the same button you used to turn off traction control.
Does traction control come on automatically?
This varies from vehicle to vehicle. It is automatically switched on when the car starts, and can be switched off at the push of a button (which needs to stay pressed for a few seconds). Alternately, the same can be done by tapping the relevant command on the display in your car.
Should you turn traction control off on ice?
Traction control will keep your car from slipping and skidding on ice. If it is stuck in snow and hence stationary, spinning the tires is only going to cause more problems.