Stop line, blocked sightline and a yellow box
You are leaving a petrol station forecourt onto a busy three-lane road. Your exit is marked by a Stop line painted across the lane and a Stop sign on a pole. A large lorry has parked in a lay-by 4 m to your left and completely blocks your view of the near lane. About 8 m beyond the Stop line is a yellow box junction marking, and past that the near lane is already queued with stationary cars. Traffic on the main road is heavy in both directions. It is 6.30 pm and it has just started to rain.
1. The road to your right looks clear. Must you still stop at the line, and exactly where should you stop?
Read the worked answer
Yes - a complete stop every time. A Stop line and Stop sign require the vehicle to come to a full stop, regardless of how clear the road looks. A rolling yield is a failure to comply.
Where: stop with the front of the car just short of the line so the line is still visible ahead of you. Stopping on or over the line puts you in the path of near-lane traffic before you have looked.
Because the lorry blocks your view 4 m to your left, the sequence is two-stage:
- Stop at the line and look left first (near-lane traffic comes from your left), then right.
- Only after the stop, creep forward a few centimetres at a time until you can see far enough up the near lane - use reflections in the lorry's windows or glass frontage as a substitute for direct sight.
Creeping forward is an addition to the stop, never a replacement for it.
2. Why must you not simply drive on into the yellow box, and where should you wait?
Read the worked answer
A yellow box marking means you must not enter it unless your exit beyond it is clear. The near lane past the box is already queued, so entering would leave you stationary inside the box, blocking the lanes you are trying to cross - the exact situation the marking exists to prevent.
Where to wait: at the Stop line. The gap between the line and the box is only about 8 m, and with a car roughly 4.5 m long you could only occupy that gap if you were certain your whole vehicle cleared the box - that is a tight margin with a queue moving unpredictably. Waiting at the line costs you nothing and keeps the box empty.
Move forward only when both conditions are met: the near lane is clear of approaching traffic, and there is space beyond the box for your whole car.
3. What difference does the rain make to your plan?
Read the worked answer
Three practical changes:
- Stopping distance on wet tarmac is roughly 1.5 to 2 times the dry figure, so the gap you need in the near lane is much larger than it looked a minute ago. Judge the gap on time-to-arrive, not on how far away the car appears.
- The queue beyond the box will clear more slowly, which increases the temptation to creep into the box behind a moving car. Resist it - the exit must be clear when you enter, not when you arrive.
- Visibility and signalling: wipers and demisting on before you move, headlights on so a driver in the near lane can pick you out against the forecourt lighting, and indicator on early so waiting traffic knows your intention.