Unfortunately, so far, the majority of the signs I've seen are not facing the street, where they will be seen by habitual drivers...no, they are facing the sidewalks, where they will be seen by walkers and bus riders. While in Los Angeles, cyclists are often drivers as well, there is a much greater divide between transit users and drivers, with little overlap (though that is changing as we add more fast and comfortable rail lines).
So while bus riders may find the suggestion laudable, they have little opportunity to put it in to practice. And the drivers whizzing by on the street (almost always above the speed limit, of course, except at rush hour) can't see the damn signs!
I've also seen the signs facing the street, but the wrong way: aimed at the backs of passing cars. The one that Streetsblog photographed also faced away from motor traffic.
This is odd since both the sidewalks kiosks and the bus shelters where these are installed include panels oriented towards the street so that drivers will easily see them.
Maybe those panels are more expensive? Perhaps it's mere cluelessness...or (cue ominous music) actual subversion of the campaign?
I don't know, and I hope future installations will actually face the drivers the signs address in most, not just some, cases. But right now I see it as a wasted effort.
Then again, I've come across only a dozen or so of these so far, so I could very well be wrong. I hope I am.