I rode about half a mile facing the wrong way, on the wrong side of a relatively quiet 2 lane road today, as a sort of thought experiment, to see what, if any, perceived advantages there might be to the practice.
here's what I thought.
•as has been suggested before, you have the advantage, such as it is, of not worrying about traffic overtaking from behind. All of the traffic you're sharing the lane with is easily visible well before it reaches your position.
• you have far more time to react to turning vehicles, in that, where right-way riders risk right hooks, where the turning vehicle is in close proximity to you, cars making lefts across your path have to cross a full lane (or more) before they get to you, giving you more time to react.
•in theory, if you're doored while wrong way riding, the door will give way (close back on the motorist) rather than remaining stationary as when you're doored riding the right way.
•to that point, a motorist exiting his car is more likely to see you coming and less likely to door you in the first place.
it's not something i'd do all the time, or even particularly often, but i was interested to find how quickly the plausible advantages suggested themselves. not sure whether i'll extend the experiment to sidewalk riding or not.