Posted speed limits assume good road conditions. Swedish law requires drivers to adapt their speed to actual conditions — in winter or wet weather, the legal limit may still be far too fast to stop safely.
Rain
On a wet road, stopping distances are approximately doubled compared to dry conditions. Water reduces tyre-to-road friction significantly. The first 10 minutes after rain begins are often the most dangerous — oil and rubber deposits emulsify before being washed away.
Snow and Slush
Stopping distances on compacted snow are roughly 3–4 times those on dry tarmac. Slush is particularly deceptive because the surface looks similar to wet road but offers much less grip. Reduce speed early; avoid heavy braking which triggers skids even with ABS.
Ice
Black ice is invisible and lethal. Stopping distances on smooth ice can be 10 times or more than on dry tarmac. From 50 km/h on black ice, a vehicle can travel over 150 metres before stopping. Warning signs of ice: outside temperature at or below +3°C, no other tyre tracks visible, smooth-looking road surface.
Exam tip: The theory test frequently asks: “the speed limit is 90 km/h — is it safe to drive at 90 km/h in icy conditions?” The correct answer is no — you must drive at a speed from which you can stop safely, which may be far below the posted limit.