Knuckle lights are LED lights that strap around your hands, over your knuckles. The lightweight LED's offer both visibility and lights your path. The motion from your swinging arms makes you very noticeable to approaching cars.
One particular advantage is that, unlike a headlamp, if there is something irregular in the dark, you are carrying 2 flashlights which you can point at the avoidable hazards. The dual purpose - safety and functionality make a reasonable choice as a solution to your runs into the darkness