At the start of the central reservation dividing a dual carriageway, you see a blue circular sign showing a single white arrow curving down and to the left, mounted on a bollard. What does this sign instruct a driver to do?
- Turn left at the next junction, since this is a direction sign showing the route to a specific destination
- Give way to any traffic already travelling on the dual carriageway before rejoining the flow of traffic
- Keep to the left of the central reservation or traffic island ahead, passing it on the side the arrow points toward rather than straddling or crossing into the lane on the other side; the same sign is used, with the arrow reversed, wherever a driver must instead keep to the right of an obstruction or island
- Slow to the speed limit shown on a nearby plate, since the arrow indicates a temporary diversion route
Why C? And why not the others?
Correct answer: C. Keep to the left of the central reservation or traffic island ahead, passing it on the side the arrow points toward rather than straddling or crossing into the lane on the other side; the same sign is used, with the arrow reversed, wherever a driver must instead keep to the right of an obstruction or island
A blue circular sign with a single white arrow curving in one direction is a mandatory 'keep left' (or 'keep right' if the arrow is reversed) instruction, placed on a bollard at the start of a central reservation or other traffic island so that drivers pass it on the correct side rather than straddling the island or drifting into the opposing lane. It is a positive instruction sign, meaning it tells the driver what they must do, not merely a suggestion. The option describing it as a direction sign to a destination misreads the plain arrow-in-a-circle design, which carries no place name or destination information at all. The option about giving way to existing dual-carriageway traffic invents a priority rule this sign does not convey, since keep-left arrows on a central reservation are about lane position, not merging priority. The option linking the arrow to a speed limit or a temporary diversion fabricates information from a plate that, in this scenario, is not described as being present at all.
Source: DfT Traffic Signs Manual, Chapter 3 — Regulatory signs: Keep left (GOV.UK)