Is your vehicle equipped with one or more advanced driver assistance systems: ABS, brake assist, traction control or stability control? When driving in snow, these sophisticated systems might not always respond in the way you expect. Don't get caught out - learn to anticipate the effects of advanced driver assistance systems!
All advanced driver assistance systems behave differently on snow...
Driver assistance systems are there to help you in an emergency: they activate the engine and brakes to help you keep control of your vehicle. On the snow, however, these electronic systems can sometimes affect your car's behaviour in surprising ways. Get to know how they work to make sure you don't get caught out.
ABS, anti-lock braking system
When you brake hard, the ABS sensor detects the locking point on one or more of your vehicle's wheels. It immediately reacts by releasing braking pressure on the wheel in question. This stops the wheel from locking and prevents your vehicle from skidding out of control. You will know the ABS has kicked in through the vibrations in the brake pedal. The trade-off is that your braking distance will be extended so be careful on icy or snow-covered roads, the braking distance can double or even triple.
Also, your ABS might get confused and fail to react correctly if there is a discrepancy in grip between the right-hand tyres and left-hand tyres, for example if only half the road is covered in snow or if the road surface is bumpy.
When driving on snow, reduce your speed and as far as possible anticipate the need to brake in advance.
ESP, stability control
The ESP detects if the wheels of your vehicle are moving in a different direction to the steering wheel (under or over-steering, for example). It corrects the vehicle's trajectory by activating the braking system and reducing the fuel injection to the engine. This limits your ability to accelerate which can be problematic, notably on uphill slopes.
If you drive on snow in a vehicle fitted with ESP, anticipate a potential drop in speed caused by this system in the event of a slight steering deviation.
EBA, emergency brake assist
When required to perform an emergency stop, you may not brake hard or quickly enough. The emergency brake assist is there to correct this. The system measures the speed with which the brake pedal is pressed and multiplies the braking pressure which allows you to reach maximum braking power almost instantly.
ASR, traction control
The purpose of a traction control system is to avoid losing control of the drive wheels when accelerating. This system is particularly helpful when starting off, in particular on snow or ice. As soon as a drive wheel starts to spin, the traction control kicks in, reducing the power to the wheel in question but without transferring it from one wheel to another (except for specific systems with an automatic locking differential). If the other drive wheel starts to spin, the ASR will reduce engine power again until both wheels recover grip.
When starting off on a slippery surface such as ice or snow, the ASR may have to reduce engine power to such an extent that the car won't start. The only solution in this case is to temporarily turn the system off.
When doing a hill start or starting off on snow or ice, if engine power is insufficient, deactivate the ASR system until you recover sufficient grip on the road and then reactivate it.
Winter tyres adapted for use with driver assistance systems
Given the increasingly widespread use of advanced driver assistance systems, tyre manufacturers now offer winter tyres optimised for use with these systems. The TS 860 from Continental’s WinterContact range is specially designed to enhance the stability control (ESP). This winter tyre is composed of purpose-designed sipes which align more easily in the intended direction of travel.
See the rezulteo test results for this tyre
In winter conditions, regardless of the driver assistance systems fitted to your vehicle, remember to adapt your speed and leave sufficient braking distance. Snow chains and socks can also be invaluable in tricky situations... don't forget to kit yourself out!