Which shape corresponds to a no passing sign?

A no passing sign is represented by an isosceles triangle that points to the right. This specific shape is used to convey the message that passing is not allowed in that particular area. The triangular shape is easily recognizable and provides a clear visual cue for drivers to be cautious and maintain their position in the lane without attempting to overtake other vehicles.

The choice of an isosceles triangle is significant because it draws attention and indicates a specific action (or prohibition) is necessary. This shape stands out compared to more common road signs such as rectangular signs that typically indicate regulatory or informational messages. Similarly, diamond-shaped signs are used for warning messages but do not specifically indicate passing restrictions. Circle-shaped signs often indicate regulatory matters, such as speed limits or yield signs, not passing prohibitions.