किस प्रकार का सड़क नियम या संकेत वाहनों की आवाजाही को केवल एक ही दिशा में प्रतिबंधित करता है?

Which category of road signs conveys mandatory orders and messages about traffic laws and regulations that must be obeyed?

Which of the following traffic signals must be treated exactly like a stop sign?

What should a driver do when approaching a flashing yellow traffic light?