Traction Control and Electronic Stability Control

By Samantha Stevens, 15 Sep 2015 Car Advice

Traction Control and Electronic Stability Control

Traction Control and Electronic Stability Control – Samantha Stevens brakes it all down… we mean, breaks!

Traction Control (TC) and Electronic Stability Control (ESC) are two active safety systems that react automatically when the grip from one, two, or even all four wheels is lost, helping the driver regain control of a wayward wheel or four.

Without the driver’s input – often without them even knowing it is happening – these systems cut engine power, apply the brakes on individual wheels, and even transfer drive to the wheels with grip while cutting power to those without.

But just because your car has ESP, doesn’t mean it can read your mind (boom, tish!) Stability programs offer an enormous safety advantage, but they aren’t infallible and can’t guarantee to catch every slip and slide. Understanding how these systems work – and what their limitations are – can not only help you in the buying process when searching for a safe new car, but can also make you a safer driver.

TRACTION CONTROL

Traction control (TC) is an electronic aid to prevent wheelspin and regain grip (traction), either by reducing/limiting the engine’s power delivery, or by applying the brakes on the wheel that’s slipping. The sensors on the wheels that are used by the Anti-Lock Braking System (ABS) detect slip, and will either cut engine power to reduce the wheelspin, apply the brakes on and off to regain traction, or even do both at once.

For example, if you have TC switched on and floor the gas pedal making the wheels slip (or spin), you will either feel the car ‘bog down’ as the engine reduces the power being delivered to the wheels, or a big hesitation as the brakes are applied.

If you have a rear-wheel-drive car and teenage boys, make sure you have TC that cannot be switched off – that big smoky burnout attempt will be nothing more than a sedate, slow start.

STABILITY CONTROL

TC systems are rather rudimentary compared with Electronic Stability Control Programs (ESP or ESC), which are far more sophisticated in their ability to regain grip and therefore control.

Where TC simply limits wheelspin, ESP can help give the driver back some control by calculating which wheels have the most grip and which are slipping, and then sending power and applying the brakes as needed by each wheel. It can take control of one wheel, or send different signals to all four, depending on the situation.

By using the car’s ABS and other sensors, even the steering input, ESP will try to straighten out a slide or correct a skid, and slow everything down so the driver can regain composure as well as control.

Ultimately, ESP cannot defy the laws of physics so sometimes it may only make for a slightly softer landing rather than a lucky escape. In other words, it cannot be relied upon to save the day; ESP is another helping hand if the situation gets sticky – or slippery.

Cars with a sportier bent, as well as 4WDs that may be used on low-traction surfaces such as sand or mud, typically have a switch to disable TC/ESP. Some cars will let you take full control if you press the ESP switch, while others secretly retain a residual hold on the car in case your talent runs out and you need assistance – whether you want it to or not.

Some models have a two-stage system, where a single press of the button partially disables the system, granting a little more freedom, while holding the button for several seconds completely deactivates it. This is mainly of interest to those who want to drive the sand dunes or take a performance car to the racetrack. However, there’s an argument that if you can drive a track without triggering the ESP, you are not only in full control of the vehicle, but also attaining maximum grip. And whether you are driving a track, road or dune, grip is exactly what you want. 

Click here to read more about other automatic braking technologies.