Not much motor traffic in the AM, but it's hard to see road debris. I have to avoid multipurpose paths because of debris, stealth runners and dog walkers, and deer. On the streets, I usually can pick out the pedestrians and runners but sometimes it's dark enough to miss them. As soon as the new tires arrive, I can start using my new dyno wheel and tame the darkness.
Psychologically, though, riding in the dark is isolating - like riding in a tunnel. I just don't like it.
-Gary