This one a rather bizarre cycling safety film from 1963, One Got Fat.
"Monkeys" riding bikes. Deaths. Odd.
Some way-cool bikes.
[Update:] I'm watching it now and someone's just been run over by a steamroller! You've got to watch at least as far as this just to hear the sound effect!
[Update 2:] Yay for Oliver Slump! He isn't a monkey, right?