What sign is typically displayed on vehicles that are categorized as slow-moving?

The correct identification of the sign for slow-moving vehicles is the red triangle slow-moving vehicle sign. This sign is specifically designed to alert other road users that the vehicle displaying it is traveling at a slower speed than normal traffic. The red triangle shape is highly visible and universally recognized, facilitating quick recognition by drivers.

This becomes particularly important on busy roads where a significant speed difference exists, as it helps prevent collisions by preparing faster-moving vehicles to be more cautious around these slower vehicles. The bright red color of the sign further enhances visibility, ensuring that it captures the attention of drivers, especially in various weather conditions or low-light situations.

In contrast, the other options do not represent slow-moving vehicles. The blue triangle sign is typically associated with specific information or services, while a red circular sign generally warns of specific rules or conditions, such as prohibitions. Additionally, a green rectangular sign is often used to provide directional information or to indicate guidance related to routes or distances, which does not pertain to the identification of slow-moving vehicles.