What does a blue circular sign signify?

A blue circular sign indicates a mandatory instruction or regulation that drivers must follow. In the context of road signage, this typically relates to actions that must be taken by road users, such as “turn left ahead” or “no entry for vehicles”. These signs are essential for ensuring that drivers adhere to specific rules for safety and traffic management.

The differentiation in color and shape of road signs serves important functions for drivers; in this case, the blue circular sign's design communicates a clear instruction as opposed to warnings or prohibitions, which are represented by other colors and shapes.