[userbinator]

It seems like one of those things that's probably more common than you think, given that you'd have to pay very close attention and know what you're looking for to see them in use.

[cortesoft]

Also something I would never see living in Los Angeles.

[sethammons]

However, living two hours away from LA in the San Bernardino mountains, our school buses were running these in the 80s and 90s.