
In the meantime, Saul Daniels in his Chatsworth Patch blog informs us that new legislation will allow the city of Los Angeles to regulate these monstrosities and perhaps get them off the streets for good, without having to post these silly signs everywhere.
I've never understood why these were allowed at all. Other kinds of advertising signs are regulated. For example, the Bureau of Street Services often lets us know how much they want to eliminate all the garage sale and lost dog signs that are posted in neighborhoods. While those signs may not be pretty, most people aren't greatly bothered by them, and they don't cause the kind of hazards and inconveniences that the billboards on wheels do.