I've always liked the idea of the fluorescent road stripes illuminated by streetlights containing mercury blacklight lamps....but that is highly inefficient.
I have noticed that the remaining mercury outdoor lights in my area - used by DOT to illuminate highway signs - are going away in favor of 3M's new highly reflective road signs, so the lighting is simply removed.
I find in areas such as the Pacific Northwest where I live, where it rains or at least is cloudy a lot of time, having reflectors embedded in the lanes really helps a lot. Streetlighting actually is a hindrance in some areas as you can't see the road as well....the DOT tends to only install streetlights at intersections and on ramps.
A newer technology we might see more of, particularly in remote areas, are LED streetlights with motion sensors, so they only turn on when you get near them. Another design dims the streetlights during hours of the early morning where there is little traffic.