Speed Limits, Stopping Distances and Following Distances
What the exam tests
This domain tests whether you can choose a safe speed, not just a legal one. It covers posted limits, the two-second rule and the physics of stopping distance on dry, dusty or sandy roads.
Core rules
- Obey the posted limit. Typical Kuwait limits are around 50 km/h in urban streets, 80 km/h on arterial roads and 100–120 km/h on expressways, but the sign always governs.
- The limit is a maximum, not a target. Reduce speed for dust, rain, sand, night, traffic and unfamiliar roads.
- Keep at least a two-second gap in good conditions; double it to four seconds in rain, dust or poor visibility.
- Total stopping distance equals thinking distance plus braking distance. Thinking distance grows in proportion to speed; braking distance grows with the square of speed.
- Sand and oil greatly reduce tyre grip, so braking distance can be much longer than on clean asphalt.
Worked example
At 50 km/h, about 14 m is covered in one second of thinking. Dry braking might add about 14 m, giving roughly 28 m to stop. At 100 km/h, thinking distance is about 28 m and braking distance about 56 m, roughly 84 m in total. Doubling the speed roughly quadruples braking distance, so the faster rider needs far more space and time.
Traps that cost marks
Treating the posted limit as a safe speed in dust; tailgating because the bike brakes well; counting a one-second gap; and forgetting that sand or rain can double stopping distance.