Overtaking a Slow Lorry on a Blind Crest
You are on a single-carriageway road outside a town, driving at 80 km/h in a 90 km/h limit. Ahead is a heavy lorry travelling at about 45 km/h, throwing up spray from a recent shower. You have been stuck behind it for several minutes. The road curves gently left and then rises to a crest; you cannot see what is beyond the crest. There is a solid white line on your side of the centre line for the next 200 metres, then it becomes broken. A car is visible in your mirror about 150 metres back, closing slowly. Your vehicle is a small hatchback with a full load of passengers.
1. Can you overtake now? Explain the factors that decide it.
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No - you must not overtake now.
Reasons:
- Solid white line on your side: you must not cross or straddle it. The line stays solid for 200 m, so overtaking is prohibited there.
- Blind crest ahead: you cannot see oncoming traffic or the road beyond the crest. Overtaking into an unseen hazard is dangerous regardless of markings.
- Spray from the lorry reduces your view of the road ahead and of oncoming traffic.
- Closing car behind: if you pull out and then have to abort, the car behind may be affected.
- Full load of passengers: acceleration will be slower, so you need a longer clear gap than usual.
The broken line further ahead does not by itself make overtaking safe - you must also have clear visibility and a gap long enough to complete the manoeuvre.
2. Suppose the line becomes broken and the crest is passed, with clear road ahead. What checks and conditions must be met before you commit to the overtake?
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Before committing, confirm all of the following:
- Visibility: you can see far enough ahead to be sure no oncoming vehicle is approaching and the road beyond is clear.
- Markings: the line is broken on your side and there is no other prohibition (no junction, bend, or hazard sign).
- Gap: there is enough clear distance to overtake and return to your lane before any oncoming traffic arrives - account for the slower acceleration of a fully loaded hatchback.
- Mirrors and blind spot: check mirrors, signal, and check the blind spot before pulling out.
- The lorry's behaviour: make sure it is not about to turn or change lane; watch for its indicators.
- The car behind: if it is already overtaking you, do not pull out.
Then: signal, move out smoothly, keep speed up, pass quickly, and return to your lane only when you can see the lorry in your interior mirror. Never overtake on a crest, bend, or where you cannot see far enough ahead.