Final answer:
The school bus stop law requires traffic in both directions to stop for a school bus on a two-lane road unless there is a physical barrier or an unpaved median, in which case only the traffic following the bus must stop.
Step-by-step explanation:
The school bus stop law is designed to protect students who are disembarking from a stopped school bus. In general, on roads with two or more lanes of traffic, vehicles traveling in both directions must stop for a school bus that is picking up or dropping off students. The exception to this rule is when the roadway is divided by a physical barrier or an unpaved median; in such cases, only the vehicles traveling in the same direction as the bus are required to stop.