I live in Austin Texas and my round-trip commute is around 30+ miles. I leave at dark-thirty in the morning and come home in the late afternoons. I travel from the outskirts of town directly into downtown Austin. Obviously, I feel most vulnerable in the dark, but not for reasons that you'd probably assume. I think I do a reasonable job with lighting and clothing to be seen, and to see. What is scary for me are things that are unpredictable. Those things are nocturnal animals (possums, deer, racoons, my friend recently ran into a coyote at 20+MPH), dogs, and downtown pedestrians. I have found that drivers in my city, for the most part, are respectful and familiar with cyclists. I do have an issue with those drivers that text while driving, and it seems as though their numbers are increasing.

I try to take mostly neighborhood streets when I can, so I minimize putting myself in harm's way. I also try to be very, very observant of my surroundings, but like anyone, sometimes I become a little complacent because of familiarity with my route. Hope this helps.