Because of a busy day, I didn't run until late in the evening. When I left home, it was 9 pm, and the sun had already set. Even though the sun was down, it was still light outside when I began my run. However, about a mile before I turned around, it was dark. I thus ran about 6 miles in the dark.
During my 17 years in Massachusetts, I ran in the early morning, before the sun was up, for several years. I had no trouble running the back roads in the dark, even though there were no street lights, because the asphalt road was a lighter gray than the trees and bushes bordering the road. My secret is that I navigated the roads by distinguishing between shades of gray. I also knew there weren't potholes that could trip me. And, the skunks heard me coming and scooted out of the way.
So it is on the Jordan River Parkway. In addition, there aren't many trees and tall bushes bordering the Parkway path, and light from the sky and from nearby buildings and parking lots shines on the path. Also, I know there aren't any obstacles on the path that could trip me.