On roads without sidewalks (in Washington at least) you are legally required to walk against the flow of traffic.

On MUPs on the other hand everyone runners and walkers included should keep to the right.

Also - in the dark, hi-viz is pretty useless.... only lights/reflectors will get you seen. I've come up on runners who probably thought they were being responsible - wearing lots of white or yellow. They are still invisible until the last minute.