What are 'amber' and 'all-red' intervals in traffic signals?

• A. They refer to pedestrian crossing phases.
• B. They describe the timing of turn lanes only.
• C. Amber is the warning phase before red; all-red ensures conflicting movements have cleared before opposing green.
• D. Amber and all-red intervals indicate pedestrian priority only.

Answer: (D)

Amber and all-red intervals describe how traffic signals manage the transition from green to red to keep intersections safe. Amber is the yellow warning phase that tells drivers the light will turn red soon, giving them a chance to stop if they can do so safely; it applies to all movements, not just pedestrians. All-red is a brief period when every direction is red, allowing vehicles in the intersection to clear and preventing conflicts as the crossing or opposing traffic moves into its own green phase. This timing is about coordinating vehicle movements for safety, not about pedestrian priority, and it isn’t limited to turn lanes or pedestrian phases.