The girls look decent and well-dressed. Are these pictures at training spots or did they pose for the camera. I do not see much traffic that they have to direct.

I think most of the pics are taken by tourists - the sight of a pretty uniformed lady executing precise military-like commands must seem otherworldly, especially when there's not many cars around.
Although some intersections do have traffic, I think depending on what time of day it is.

I wonder if higher-traffic intersections are higher-paying? I'm sure there are intersections that are more desirable than others.

Hmmm ...I doubt that some intersections are higher-paying - isn't communism supposed to be all about everyone being equal?
And now that you brought it up, and thinking about it, there probably are intersections that are more favorable to work at than others. But to me the favored ones would be the ones with less traffic - there would be less chance of being run over or injured. In theory, the more dangerous ones should be the higher paying ones.

Pay would probably be based on seniority or rank.