I drive with my headlights on, all the time. Someone told me that he had a lot of close calls, with people pulling out in front of him, until he started doing this. Apparently some car colors sort of blend in with the pavement, and people just don't recognize it as an oncoming car.
Years ago, I gave my dad a mesh vest that had reflective stripes on it. It was designed for runners, and was light and airy enough to be comfortable on a hot day, and loose enough that he could wear it over a jacket on colder days. It was intended for runners. I wish everyone who's going out exercising would get one.