Near Sluiskil you are driving at 80 km/h behind a vehicle doing 25 km/h; overtaking it would have taken about 87 metres. Just before you start, the vehicle ahead speeds up to 60 km/h. You are still doing 80 km/h. How much overtaking distance do you need now?
- ✓ About 240 metres, much more than the earlier 87 metres
- About 40 metres, much less than the earlier 87 metres
- Still about 87 metres, because you yourself are still doing 80 km/h
Correct answer: About 240 metres, much more than the earlier 87 metres
Explanation
False — You only look at your own speed. The overtaking distance depends on the speed difference with the vehicle ahead: 60 x your speed : difference, so now 60 x 80 : 20 = 240 metres
Why learners get this wrong
- You think a smaller speed difference gives a shorter overtaking distance, but it is the other way round. The smaller the difference, the longer you drive alongside the vehicle: 60 x 80 : (80 - 60) = 240 metres
- You only look at your own speed. The overtaking distance depends on the speed difference with the vehicle ahead: 60 x your speed : difference, so now 60 x 80 : 20 = 240 metres
Topic: Calculating overtaking distance: the 60-formula and the blind spot
Read the rule: Core: Calculating overtaking distance: the 60-formula and the blind spot
Sections
- Challenge: Calculating overtaking distance: the 60-formula and the blind spot
- The model: Calculating overtaking distance: the 60-formula and the blind spot
- Core: Calculating overtaking distance: the 60-formula and the blind spot
- Why it matters: Calculating overtaking distance: the 60-formula and the blind spot
- Active recall: Calculating overtaking distance: the 60-formula and the blind spot
- Teach back: Calculating overtaking distance: the 60-formula and the blind spot
- Memory hook: Calculating overtaking distance: the 60-formula and the blind spot