To be fair, people should definitely get fines for passing school buses. I'm more mad at the state for being different than the rest of the country and including divided highways in their school bus law.

“Highway” means a lot of things depending on the context. Sometimes it’s an interstate system with on and off ramps, but it also refers to a non-residential road (though in western New York, I’ve seen houses with driveways that connect with I-84, so who the fuck knows what the deal there is).

For the purposes of stopping for buses/emergency vehicles, a divided highway is any nonresidential road with a raised median such that a car is unable to turn around at any given place. At least in my state.

The only "highway" in the US where you're absolutely not allowed to stop (under normal circumstances) is a "controlled-access highway". The majority of which is the US Interstate system. Some state highways are controlled-access as well.

But I feel it's important to clarify: School buses do not stop to pick up children on those sort of roads. That would be insane.

Not sure where you live, but here's the law for Utah (where I live):

(3) The operator of a vehicle need not stop upon meeting or passing a school bus displaying alternating flashing red light signals if the school bus is traveling in the opposite direction when:

• a) traveling on a divided highway;
• b) the bus is stopped at an intersection or other place controlled by a traffic-control signal or by a peace officer; or
• c) on a highway of five or more lanes, which may include a left-turn lane or two-way left turn lane.

Note how it only specifies driving in the opposite direction of the bus.

Source: https://le.utah.gov/xcode/Title41/Chapter6a/41-6a-S1302.html