We live rurally, but less than a third of a mile from a busy main road.
I would be perfectly happy to go for a walk at any time of the day or night around here, but after dark, would prefer to be in the fields so I am not visible from the roads.
Out of sight of casual passers-by in cars, I feel that the biggest danger to me by far is that of falling, but that is true in daylight too, and age 60, it's a risk that I am still prepared to take.
That said, it is actually quite rare for me to go out in the dark (apart from in the garden) - I don't have a dog, so don't have a good excuse, and not surprisingly, OH is not happy about my doing it.
Earlier this year, I did go out after dark a few times to try to spot badgers, having noticed many active setts on my daytime walks. I was unsuccessful, but then realised that with binoculars, I can actually actually see a sett from our bedroom, and as the evenings got lighter, I was able to watch a badger family frequently as they came out to play and forage before dark. No need/excuse to venture out in the dark any more.
I must admit, I would be very nervous about being out alone in the dark in a town or built-up area, once the streets started to empty. That's not something I would do without good reason!