What do circular-shaped signs with red trim signify?

Circular-shaped signs with a red trim are universally recognized as indicating prohibition. This design is standard in many traffic systems around the world, signaling drivers to refrain from certain actions, such as not entering a restricted area or not performing a specific maneuver (like a U-turn). The red color evokes strong caution and urgency, making these signs effective at communicating restrictions.

In contrast, information signs typically have different shapes and colors, like rectangles or blue circles, conveying details rather than prohibitions. Regulatory actions, while they may align closely with prohibitory signs, encompass a broader range of regulations, including minimum speed limits or specific driving rules that might not involve outright prohibitions. Warning signs are generally triangular or use bright colors to alert drivers of hazards ahead, not to restrict actions explicitly. Thus, the design and color coding of circular signs with red trim distinctly indicate prohibitory regulations.