Adapted speed: the law asks for more than the sign

Road conditions, visibility, traffic — situations where you must drive below the posted limit.

You will learn, among other things:

Speed must be adapted to conditions
When you must slow down
90 signed, 50 metres of visibility
Driving to the sign is not a defence

Shows a situation where speed must be adjusted according to difficult conditions, just as the lesson describes.

Illustrates speed adaptation in a curve with limited visibility, which complements the lesson's theme on adjusted speed.

Rule

Speed must be adapted to conditions

The Traffic Ordinance requires you to adapt your speed to conditions, not just the sign. If the road is slippery, wet, dark, or crowded, you must slow down even if the sign says 70. Driving at the posted limit can count as negligence.

Checklist

When you must slow down

The posted speed limit is a maximum, not a recommended speed
Reduce speed in poor visibility, darkness, fog, or glare
Adapt speed to road conditions: ice, snow, water, or gravel
Slow down in heavy traffic, near intersections, crossings, and children playing
Keep enough distance to stop safely within your visible sight distance
You are always personally responsible for choosing a safe speed for the situation

Example

90 signed, 50 metres of visibility

Sign says 90 km/h. Heavy snow, visibility 50 metres. Holding 90 is illegal. You couldn't stop in time for anything appearing within your sight line. 40–50 km/h may be right.

Exam trap

Driving to the sign is not a defence

If you crash because you drove to the sign instead of to conditions, insurance can cut your payout, and the prosecutor can charge you with careless driving.

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