What does a no U-turn sign mean?

A no U-turn sign indicates that making a U-turn is prohibited at that location. The primary purpose of this sign is to enhance safety and traffic flow by preventing maneuvers that could lead to collisions or disrupt the orderly movement of vehicles. U-turns can be particularly dangerous in heavy traffic, at intersections, or in areas where visibility is limited. Therefore, the presence of this sign serves as a clear instruction to drivers, ensuring they understand that reversing direction in that manner is not allowed.

The other choices do not accurately reflect the meaning of the no U-turn sign, which is specifically focused on prohibiting U-turns rather than allowing or restricting other types of turns. For example, while turns in a specific direction might be permitted or restricted elsewhere, they do not apply in the case of a no U-turn sign.