Overtaking a slow truck before a hidden junction
You are on a two-lane rural road with a 100 km/h limit, following a heavily loaded truck at about 55 km/h. You have been behind it for 4 km. The road ahead curves gently left and you can see perhaps 250 metres of clear straight before the curve. There is a solid white line on your side that changes to a broken line about 80 metres ahead. A side road joins from the left just before the curve - you can see the junction sign but not the mouth of the side road itself because of a low hedge. Your vehicle is a 1.3-litre hatchback with two adult passengers and luggage. A car is visible in your mirror about 150 metres back, closing steadily.
1. Assess whether an overtake is safe here. Break the decision into the three separate constraints.
Read the worked answer
Three constraints must all be satisfied:
- Legal/marking: You cannot begin the overtake across the solid line. The broken line starts 80 m ahead, so any overtake must begin after that point - the solid line is not a suggestion.
- Visibility/distance: After the broken line you have roughly 170 m of visible road before the curve, and the junction mouth is hidden by the hedge. An overtake at a closing speed of about 45 km/h (100 vs 55) needs the whole manoeuvre plus a safety margin completed inside visible road. 170 m is marginal at best, and the hidden junction means a vehicle could emerge into the space you plan to use.
- Performance: A loaded 1.3 hatchback with passengers accelerates slowly; the time exposed in the opposing lane will be longer than in a solo car, widening the exposure window.
Conclusion: do not commit now. Wait until you can see through/past the junction and have clear road; the closing car behind also removes your margin for aborting.
2. The car behind is closing. How does that change your plan, and what mistake must you avoid?
Read the worked answer
A closing car behind reduces your safety, because if you pull out and then must abort, you are re-entering a lane occupied by a fast-approaching vehicle. It also tempts you to hurry the manoeuvre.
Avoid: pulling out partly to 'claim' the gap, or accelerating hard to beat the car behind into the overtake. Both convert a waiting problem into a collision problem.
Plan: maintain your following distance to the truck so you keep visibility past it, signal early and clearly so the car behind understands your intention, and let it pass or settle if it is determined to overtake you first. Only begin the overtake once you are past the solid line, past the junction hazard, and have clear sight of oncoming road with a margin you would still be comfortable with if the hatchback accelerated more slowly than you expect.
3. Halfway through the overtake, you see a vehicle nose out of the side road. What is the correct response?
Read the worked answer
Abort, don't race. If you have not yet drawn level with the truck, brake firmly and drop back behind it - you still have the truck's lane as a safe place to return to. Do not swerve right into the opposing lane to 'go around' the emerging vehicle.
If you are already alongside the truck, you cannot drop back safely; then you must slow and hold your position only if there is clear road ahead, using horn and lights to make the emerging driver aware, and be ready to stop. The key judgement is that an overtake is only committed once there is no safe abort; until then, the default answer to any new hazard is to return behind the truck.