What is the purpose of box junctions?

Answer: C — To prevent the junction from becoming blocked

The purpose of box junctions is to prevent the junction from becoming blocked. These are marked areas on the road, usually with yellow crisscross lines, that help maintain the flow of traffic at busy intersections. When drivers enter a box junction, they must ensure that their exit is clear before doing so; this helps to avoid situation where vehicles become trapped within the junction, impeding the movement of other vehicles and potentially leading to congestion or accidents. Box junctions are particularly important in busy urban areas where traffic flow needs to be managed effectively to ensure safety and efficiency on the roads.