It's more efficient for them that way, Sammy. But my school didn't bus to the vocational co-op unless you were a special needs student, and it still doesn't bus non-special needs students today. My brother will be doing the same thing I was my senior year: driving to the co-op for a computer class first thing in the morning, then driving to his home school after that class finishes.
As for how it'd normally work if you weren't going to a vo-tech school: getting off one at one place, and then boarding another at that place. It's how the private schools in my area bus their students home after school, since they contract out to the same company the public schools do.