Properly equipped for
sheet ice 

Stay cool! - Five tips on giving slippery conditions the slip

Make that vital mental adjustment from summer to winter!
You now need to take fog, snow and icy road conditions into consideration. Reckon on longer journey times.

Keep your distance from the car in front!
In winter, stopping distances on wet or icy roads are substantially longer.

No sudden changes of direction or speed!
Look ahead when driving on ice or snow, and brake gently even on straight roads.

Don't panic if you skid!
Don't brake! but go into neutral gear and steer gently against the direction of the skid.

Don't head towards a gradient!
Gently apply the handbrake - the simulated differential lock prevents the drive wheels from spinning.
But be careful: Of course this only works for vehicles with handbrakes that act on the drive wheels.