Final answer:
Vehicles must stop and remain stationary when a school bus is stopped on a road with fewer than four lanes to ensure the safety of children.
Step-by-step explanation:
When a school bus is stopped on a street or road which has fewer than four lanes, all vehicles in both directions must stop and remain stationary until the school bus has turned off its red flashing lights and begun to move again. This law is put in place to ensure the safety of children boarding or alighting from the school bus. It's similar to the rule that requires stopping at a red traffic light for safety reasons, even if a vehicle contains a pregnant woman in urgent need of medical attention.
Although there might be situations where breaking a traffic law could seem to have more utility, such as going through a red light to reach a hospital quickly at 4 am, the general rule is to increase safety for everyone by obeying traffic signals and stopping for school buses.