What is the meaning of the following traffic signs?

1. Give right-of-way on a narrow road.
2. Correct answer: The number of lanes on the road is decreasing.
3. Careful! One-way traffic ahead.
4. Entrance to a single lane one-way road.

WhyThe sign shows that the number of lanes decreases ahead: move into the lane you need in advance. In the similar version there are more lanes.