Which vehicles have priority when traffic on the main carriageway is coming from the right?

The correct choice highlights an important rule of the road known as right-hand traffic priority, which establishes that vehicles approaching from the right have precedence over those joining from other directions. In scenarios where traffic on the main carriageway is entering from the right, these vehicles maintain priority due to the standard traffic convention that dictates the flow of movement.

This means that any vehicles attempting to join the flow of traffic from the left would need to yield to those coming from the right. Similarly, vehicles in both the left and right lanes must also give way to incoming traffic from the right. The regulation helps maintain a smooth traffic flow and enhances safety by reducing the likelihood of collisions where vehicles merge into lanes. Thus, understanding this rule is essential for all drivers to navigate intersections and merge safely in alignment with established traffic laws.