I agree with Andrew P. The safest time appears to be in the early morning before rush hour traffic. I cycle at night, and with school out the teenage boys are a pain in the butt. I have worked midnights for over 20 years. There are a lot of drunks out there. On Friday and Saturday evenings, no one drives the speed limit. They either drive real slow, or real fast and pass on the right. I have had my car totaled twice by drunk drivers. I cycle at night, but I watch for lights in my mirrors and ride on the far, far shoulder or even the sidewalk. I'm a little more fragile than automobiles.