A couple of years ago I travelled solo in Naples, and as a women merely took the usual precautions (NO, that does not mean fanny backs & group tours)-- but being from NYC, I was just always aware of my surroundings and acted accordingly. I found Naples to be a wonderful city, friendly, vibrant, and fairly safe. The only thing you might want to check on is the garbage strike, not sure if it is still going on. As for the traffic, I found it no worse/better than any other major city. And yes, cars, motorbikes etc generally DO STOP at lights, and let people cross-- unlike some of the pr that comes out of Naples tourist sites. Just look before you cross and move along,,,, ie don't linger!