I've just created these illustrations to correlate riding positions with motorist line of vision, to illustrate the disadvantages of wrong-way and/or sidewalk riding. One important thing it shows, which was not obvious to me before I took a safety instructor training a few weeks ago, was that riding the wrong way on a sidewalk is even worse than riding the right way on a sidewalk, due to where drivers tend to look.
Please comment. The biggest weakness, in my opinion, is that the field of vision of drivers is very subjective, and I just sort of made up what I thought it would be, based on my own habits and not on any kind of scientific study. I also see a few other nitpicky things already that I should do differently, but I'll wait and see if anyone else says the same.
The following picture shows bikes riding with traffic, from either direction, on the street or the sidewalk. Notice the bikes in the traffic lane are more obvious than those in the sidewalk.
The next picture shows bikes riding against traffic, from either direction, on the street or the sidewalk. Notice the bikes coming from the right side are probably completely out of the driver's line of vision, and even from the left side, visibility is questionable.