Winter and slippery roads

Winter road conditions

• Winter conditions means that at least on some part of the road there is snow, ice, frost or a combination of liquid water and snow/ice (also known as slush).
• There are certain guidelines that you should follow when starting a preheater before you need to start driving. These guidelines are; 90 minutes before driving when it's below -15 °C, 60 minutes before driving when it's between -15 and 0 °C, 20 minutes before driving when it's 0 to +10 °C. These guidelines are there to minimize the negative effect on the climate.
• Although having the car started while scraping the windows will make it easier, it´s recommended to not do that since it´s bad for the environment. The best is to scape the windows first, then start the car and then drive away immediately.
• When it´s cold outside, for instance during winter, and you've just started the engine, the temperature indicator will often be very low or zero as indicated in this picture (image 1). This is perfectly normal and you should not have to be concerned.

Image 1: When starting the engine when it's cold outside then this is normal

• Sometimes in a question at the driving theory test it refers to being “extra” attentive while driving. You should of course always be attentive while driving, whether it´s summer or winter. However, being "extra" attentive during winter is mainly used to refer to slippery road conditions, when it is freezing or if it had been freezing recently. When it for instance has been above 0 degrees several days and nights, and hasn't been snowing or raining (or hailing), then you probably don't have to be "extra" attentive.
• Sometimes you’ll encounter a road sign that indicates that the road might be slippery like for instance in this picture (image 2). There is however no apparent rain on the road nor does it seem to rain. And there are no signs for winter road conditions. Therefore, you do not have to adjust your driving or do anything in particular.

Image 2: Despite the sign you can drive as usual

• It is recommended to not use the full beam headlights when there is snow, because the snow will often lead to worse visibility when you switch on the full beam.

Slippery roads and ice

• Slushplaning is similar to aquaplaning, the difference is that it is caused by slush, which is a combination of liquid water and snow/ice. You should always be aware of the possibility of slushplaning during winter road conditions.

If you’re driving on for instance a country road, and even if there only is snow on the hard shoulder you should be aware of the risk of slushplaning, in case you need to swerve on to the hard shoulder for some reason.

• The beginning of the winter is generally more dangerous than the middle of the end of the winter, because you think that you still have a good grip, but the roads are becoming slippery (for example due to ice or snow). This is a more dangerous period because you have been driving a long time without winter road conditions and all in the sudden you need to be aware of these slippery conditions.
• Freezing rain is rain which temperature is below zero degrees and freezes when it hits the ground or something else.
• You should always be attentive while driving, whether it´s summer or winter. Sometimes a question at the driving theory test refers to being "extra" attentive when driving during the winter, these questions mainly refer to slippery road conditions. Even when the temprature is several degrees plus, then sometimes you still have to be “extra” attentive, for instance when there is still snow or slush on the road, because this can make the road slippery.
• Normally you hear slush splashing underneath the car when driving through it, but if you don't hear that then probably it´s frozen and thus more like ice.
• When you’re standing still and want to drive away on a slippery road, for instance due to snow, then you should release the clutch carefully and accelerate gently in order to prevent wheelspin. Also keep in mind that staying in higher gears will help preventing wheelspin.
• When you’re about the turn left or right on a very slippery road, for instance when there is a lot of snow of the road, then you want to avoid wheelspin. So in order to avoid wheelspin when turning you should; keep the highest gear possible, maintain a low pressure on the gaspedal, and (if possible) avoid stopping.
• Junctions are often more slippery during the winter than straight parts of the road. This is because many cars often stop at junctions, this leads to the snow being pressed upon a lot more, thus resulting in the snow becoming more like ice.
• Be aware that if you’re driving over a bridge even when the temperature is several degrees plus and a river or watercourse flows underneath the bridge, then the surface of the bridge might be slippery, even though it´s not freezing outside. This is because the river or watercourse leads to the surface of the bridge being exposed to cold and humidity from more directions.

Also be aware that there generally is a higher risk of skidding, both on bridges and on flyovers, because the surface is being cooled by cold air from both above and the below the bridge/flyover.

• Even during the summer, roads can be slippery. Oil residues, dirt, tyre particles and exhaust fumes are accumulated on the road and can be dissolved and washed out when it starts raining after a long period of dry and hot weather, resulting in the road becoming slippery.

Additionally, tar in the asphalt can also rise to the surface of the road on hot sunny days, also resulting in the road becoming slippery.

• Hard-packed snow means that the snow has been pressed upon hard and/or many times, for instance at junctions where cars often stand still. Hard-packed snow is similar to ice and thus is a lot more slippery than "normal" snow.
• Be aware that even when the temperature is for instance between 0 and +4 degrees the road might be slippery, because although it isn't freezing it might have been freezing for some time before and ice could still be on the road.
• Being trained how to cope driving on slippery roads can either be good or bad. It´s good that this kind of training prepares you how to deal with slippery road conditions and thus dangerous situations. However, the downside can be that you could become too confident in your own skills and this can lead to risk-taking behaviour.
• Aquaplaning happens when water cannot be led away efficiently to the sides of the tyres and the tyres are unable to have enough contact with the road, which then that could lead to the tyres (and thus the car) being lifted up to the water surface, as indicated by this illustration (image 3), resulting in the car skidding uncontrollably.

Image 3: Aquaplaning