Speed limits, following distance and stopping (hraði, fjarlægð og hemlun)
What this domain tests
Default limits, the difference between the limit and a safe speed, and your ability to estimate following and stopping distance.
Default limits in Iceland
- 50 km/h in built-up areas (þéttbýli) unless signed otherwise; 30 km/h in many residential streets.
- 90 km/h on rural roads with a sealed surface.
- 80 km/h on rural gravel roads. Lower signs override these. The limit is a maximum for ideal conditions - rain, gravel, darkness, wind and unfamiliar roads all require less.
Following distance
Use seconds, not metres. Pick a fixed object and check that at least two seconds pass between the vehicle in front and you. Make it three or more in rain, on gravel, in tunnels, in darkness, or behind a large vehicle that blocks your view. At 90 km/h two seconds is already 50 metres.
Stopping distance
Total stopping distance = reaction distance + braking distance.
- At 90 km/h you travel 25 metres every second. One second of reaction time is 25 m before the brakes even bite.
- Braking distance rises with the square of speed: doubling speed quadruples it.
- On dry asphalt a motorcycle needs roughly 40 m of braking from 90 km/h, so about 65–80 m in total. Wet asphalt roughly doubles it; gravel is worse still.
Worked example
A tired rider at 90 km/h reacts in 1.5 seconds instead of 1: 1.5 × 25 = 37.5 m of travel before braking, plus about 40 m of braking - roughly 78 m to stop, more than the length of a football pitch, for a hazard he could see only 60 m away.
Traps
Quoting following distance in metres rather than seconds. Believing ABS always shortens stopping distance - on gravel it can lengthen it. Forgetting that the 90 km/h limit applies only to sealed rural roads.