I find a bar end mirror on the left side really helpful. For night riding, I find a powerful handlebar and helmet light a great combo. When you are turning, you can look and see where you need to go. The helmet light also allows you to look at the drivers about to pull out in front of you. I use two mi-newt minis. Also some kind of spoke lights. Planet bike super flash on the back of the helmet and one on the rack too.