Back in 70s when I was in elementary school, I remember that during one of the safety films that it was urged that for safety we walk and ride against traffic. As an adult, while I can understand the logic of walking when facing traffic, riding on the other hand seems nothing like danger -- for both the bikers as well as drivers.
Unfortunately though, this lesson seems to have carried on. Not to mention passed down to the next generation. How long this will last is anyone's guess, but at least some cities have taken the initiative to put up signs like this around the busier roads and neighborhoods.