The Original Old-Time Radio BBS

I've been searching the internet in vain for any information on a 60s and/or 70s vocal group that sang a National Highway Safety Seat Belts radio PSA. The group sounded like The Nashville Brass with singers. Or could it have been the Johnny Mann Singers. Or (unsure of spelling here) a terrific group called either the Jay's With Jamie or the Jay Sylvia Singers. Here's how the song went. "People who do. They are the greatest people. People who do...Buckle Up!" This well-known jingle was sung by a vast number of singers. But I'm interested in the pop vocal group who did it. And if anybody has a copy, and it's not illegal, could they send me a copy. Or tell me where I can get a copy? That is, without any copyright or copying wrongdoing. If all else fails, I will write the National Highway Safety Council, or whatever they call themselves nowadays. But waaaay before I ask the government to help me, can anyone here tell me? Furthermore, does anyone have any information on the aforementioned Jay's With Jamie (etal)? They recorded one or two LPs, which were very, very popular with DJs. They got a LOT of airplay. But they were mainly known for their singing commercials. Thank You!