I started Kindergarten in 1980, and I never knew anything else but red & yellow lights.
I don't remember the swing bar when I went to school, because I'm sure I would've walked into it a few times. I think that came after 1993. Same thing with the STOP sign that swung out. (And NJ only requires 1, not 2, stop signs on school buses).
Relatively recently the state required the white strobe on the top of the bus, which I find useless.
We also walked to the bus stop about 1/4 mile (5 minutes) away at a T-intersection in the neighborhood in elementary school. After we got on the bus, it backed up into the T where we feared the bus driver would back into a drainage ditch off the side of the road and we'll roll over (which was, in hindsight, a really small ditch and we definitely wouldn't have rolled over). All stuff that's rare or prohibited now.