We got movie tickets to special showings just for crossing guards. I remember seeing Star Trek: The Motion Picture and Popeye. We also had a shot at being selected to go on TV as a panelist on a sort of kid-sized game show. Being on TV is nerve-wracking when you’re 9.
My son’s school does it; he’s about to start the 6th Grade, so I suppose he’ll be starting soon himself.
They work in teams of three - two kids with stop signs at the end of broomsticks to stop the kids/cars, with one on each side of the street, and one commander with a whistle. They wear reflective vests and never leave the sidewalk.
Around the same time that kids stopped delivering newspapers door-to-door, and those jobs went to grups in cars.
Huh. It’s always cops around here. since they have to be able to stop the cars. Never even occurred to me that it might be done by anyone else–kid or adult. There are only a few official crossing spots.
We called them safeties, too. It must have been sixth grade; I went to a different school in fifth, and fourth seems a little young. I don’t remember any crossing guards of any age at any of my schools (all the way from K-12). My job was to patrol the playground duting lunch and recess.
Safety patrol must still exist in Palm Beach, FL, because the kids fill a train for their annual field trip to Washington DC. Palm Beach Post 2016 article
FWIW, I grew up in the northeast, NY state in the 70s and early 80s, and I never ever saw student crossing guards. They were always moms (or at least women) with spare time who did it. And they were only assigned around grade schools (grades K thru 5). Middle and high school students didn’t need them and would not have payed any attention to them anyway (student or adult*!*) 
I remember the older kids being crossing guards, and I’m pretty sure they were called crossing guards.
This wiki article confirms both names.
No mention when students stopped doing it, or if they ever did. Sounds like they still do.