I try to wear colors that will contrast with the surrounding environment. This creates high-visibility (or hi-viz). It is true that most folks think international orange or the neon yellow of road workers, etc. The background color changes from season to season. So, you need to learn ahead what to expect and plan accordingly.
But, in truth, any color that creates a high-level of contrast, and helps an oncoming driver or a hunter see you and avoid you will work. Hence, my rain ponchos are brights shades of green or even sky blue, to contrast against the local color palette. My basic palette, as explained above is Carmen Miranda of "dancing fruit basket lady fame from the 1930s." You get the idea.
This is also why I counsel against ponchos or outer parkas in subdued colors, like: black, brown, olive, forest green, navy blue, bordeaux or wine color, etc. I also counsel wearing really bright hats, or headlamps, even mounted backwards, as someone suggested above.
I recall that some years ago, like several decades, Mercedes Benz mounted an epic study to determine the best car paint color for safety / visibility in low light conditions. Surprisingly, white was the runaway winner in all weather. Except in a white-out snow storm (one would not normally be walking anyway), this would create optimum contrast.
Hope this helps.
