It’s known by many acronyms by different car manufacturers, but there can be no doubt that stability control is becoming a more and more common driver aid fitted to new cars. The Australian government have now made it mandatory on all cars being built here or arriving on our shores.
What’s all the fuss about? What is stability control and how does it work?
There will always be those of us who prefer not to have sensors dictate the attitude of our driving. Those who would prefer to learn the skills of threshold braking than have ABS fitted to the car. Those who would prefer to learn throttle control with their right foot rather than have the Traction Control system engaged.
Heck, I’m probably one of them. In testing various cars, I’ve seen my own braking stop in a shorter distance than ABS can. The majority of vehicles can be launched harder with the traction control off, than with it on. Most times because there is not enough leeway given to performance and the car bogs down. There have been some we’ve tested though, where the traction control sensors couldn’t cope with the amount of grunt being dropped at the back tyres and fried them to shreds.
There’s an answer as to why I’m not totally against all these technologies of course and it’s a pretty basic one. A good driver, when concentrating in ideal and expected conditions, can do all of these things, some of the time. The systems, although not perfect, do it consistently and repeatedly all day long in any conditions.
Electronic Stability Control is one of the most argued about driver assists in a modern car. Why? Because it is the most invasive of them all. When ESC takes over control of the car, you know it.
ABS, Traction Control, and the like, attempt to replicate a good driver. But Electronic Stability Control, to be contentious, is not an assist I believe I can replicate at ANY time. Here’s why :
If I, as a driver, sense my car is going into a spin or a slide, I can lift off the throttle, hit the brakes, turn into the slide or anything else involving the steering wheel and pedals at my disposal. What I can’t do, is brake an individual wheel that has lost traction to maintain longitudinal or lateral attitude of the car.
ESC on the other hand, can do exactly this. It utilises the car’s existing ABS systems to determine whether an individual tyre is skidding or (depending on the exact system) has lost a significant proportion of it’s traction. By braking the individual wheel where the traction loss has occurred while allowing the others to continue turning smoothly, the ESC can get a car back onto it’s original intended course and get it back to where it can slow and turn again properly.
The ESC keeps an eye on wheel speed relative to road speed and also watches the car’s yaw angle. The bigger the yaw angle, the more serious the slide is. The more serious the slide is, the more application of the ESC’s abilities are directed toward the road.
It’s a safety net that gives you time to recover from a wayward situation(such as hitting a patch of oil on one side of the road) before on-coming traffic has time to have a head-on with you or before you’re off the edge of the road into a gum tree.
What if you intentionally want to have a drift around a corner in your performance vehicle? What if you want to do donuts? That’s where the ESC OFF switch comes in. For the rest of the time, it’s a driver aid that does more than the driver behind the wheel can physically do themselves.
Aussie government research shows that single vehicle accidents are reduced by as much as 27% when ESC is fitted. Let’s just hope that no-one tells them about the off-switch.
Michael Adams from Test Driven Australia
Article originally written for Infinite-Garage