A Guide to Stability Control

Stability Control is the most important safety device in an automobile since the seatbelt.

Because of its proven effectiveness in reducing single-vehicle crashes, and preventing rollovers, governments across North America and Europe have made plans to require the technology on all new vehicles.

It prevents cars from skidding in a curve unintentionally. The technology works in most cases without the driver realizing that they have been in danger.

It protects drivers from minor indiscretions such as unexpectedly finding themselves in a tight corner or on slippery pavement.

Stability Control doesn’t override the laws and it does not promise to. You may still be unable to turn around or follow the conditions if you travel too fast.

Stability Control is a very valuable technology. However, it is important that you note that not all systems are equally effective.

Different names are used by car manufacturers to describe their technology. There are over 20 acronyms in the industry.

ESP was originally an acronym for Electronic Stability Program. This is a pun on Extra Sensory Perception. The technology uses sensors to monitor driver behaviour and driving conditions.

Stability Control was first introduced on a production car in 1995 on the Mercedes-Benz S Class luxury flagship sedan. However, it was later developed by Bosch electronics and made its way to other cars soon afterwards.

ESC stands for Electronic, although it is more commonly used today.

A brief history lesson is necessary to understand how Stability Control works.

Stability Control was born out of anti-lock brakes (or ABS) (Anti-lock Braking System).

ABS systems automatically stop the car in an emergency situation by clamping and releasing the brakes 20 times per second, while the driver presses full force on the pedal.

Again, the driver may not be aware that the technology is in use.

ABS stops the brakes (and thereby the tyres!) from locking and allows the driver to steer around obstacles. It’s especially useful for wet weather braking.

To make ABS work, ABS cars needed to have extra sensors that could monitor each wheel’s speed.
Engineers found a new application for these sensors, and created Traction Control.

This is where the speed between the two driven wheels and the other two is always compared.
The system intervenes when one wheel is traveling faster than the other and applies brakes or cuts engine power until vehicle speed is reduced. All four wheels then travel at the same speed.

If, for example, the rear-drive car’s rear wheels spin faster than the front wheels (which indicates the vehicle’s real speed), then the traction control would be activated within milliseconds.

It happens the same way if the front wheels spin quicker than the rear in a front-drive vehicle (when equipped with Traction control).

The most common use of Traction Control is to detect unintended wheelspin while accelerating from a stop, such as when driving up steep slopes or aggressively out of corners.

Stability Control was then built upon ABS and Traction Control. It was then easy to add a steering wheel sensor, throttle sensor, and a sensor that measures the car’s angle.

Engineers also discovered a way to apply brakes to individual wheels to bring the car under control in a safest and most efficient manner.

Modern technology makes it so easy to out-manoeuvre a race car with Stability Control. The system can brake individual wheels and do what the driver is unable.

All of this takes a lot of computer power.

Stability Control systems continuously monitor and process hundreds upon hundreds of times every second the following information.
Vehicle speed (wheel sensors).
Steering input (steering wheels sensor)
Acceleration (throttle sensing)
Braking (brake sensor).
Pitch or ‘lean’ the car (yaw sensor).

Complex algorithms and thousands of hours spent testing and calibrating calibrations allow engineers to develop Stability Control systems that fit each vehicle’s unique characteristics such as weight, engine power, and tyre grip.

Some cars are designed for conservative drivers. The Stability Control system can intervene at the first sign of skid.

Some cars, especially performance cars, have a slightly higher threshold due to their higher grip.

Stability Control has been proven to be lifesaving, despite its varying effectiveness.

International studies of single-vehicle crashes involving vehicles equipped with Stability Control show that there have been significant reductions in serious injuries.

This is one reason why the European New Car Assessment Program and the Australian New Car Assessment Program (ANCAP), decided recently that only vehicles with Stability Control could receive a Five Star safety rating.

ANCAP, like its European affiliate is an independent body that crashes tests vehicles to higher standards then those imposed on them by governments.

It is meant to be a guideline for car safety. All top-selling models are tested.

ANCAP is supported in part by Australian and New Zealand automobile clubs, State government road and transport authorities of NSW and South Australia, Queensland and Tasmania, Western Australia, Western Australia, and Western Australia.

Check the ANCAP website to verify if a vehicle has stability control. Some older Five Star ratings did not require this technology.

Ensure that you check with the car manufacturer if the model you are looking at buying has Stability Control.

Modern luxury cars come standard with Stability Control, however it may not be available for all models.