Final answer:
When a school bus activates red lights and stop sign on a two-lane road, traffic from both directions, behind and opposite the bus, must stop. Side-approaching vehicles are not typically involved.
Step-by-step explanation:
When a school bus activates its red lights and stop sign on a two-lane roadway, the traffic that must stop includes:
- Vehicles approaching the school bus from behind.
- Vehicles approaching the school bus from the opposite direction.
Vehicles coming from the side are not typically on the roadway and would not be relevant in this context. Thus, the correct answers are vehicles approaching the school bus from both directions – behind and opposite – to ensure pedestrian safety, particularly for students entering or exiting the bus.