Iceblossom, I end up with about 4-5 hours sleep per night, too, but it is self-inflicted due to bad habits. I want to improve my sleep habits (at least, I tell myself I do), but thus far I haven't succeeded in getting myself to bed earlier consistently so as to break out of the current pattern. On the occasional night I do better, I just lie awake until my normal time of falling asleep.
I had decided that my grays would represent gray skies, which was a more appealing idea to me than asphalt. The black neutrals could represent a blacktop country road (which I guess is quite similar to asphalt, but it sounds more picturesque, LOL).