The Norwegian (soon to be international) company Morild, is making garments made of thread with reflective qualities, so that you are safe from cars, in the dark! Fantastic concept, I think.
I bought from them a few sequins that do the same, reflect light, in silver and gold, and sewed some on a few of my hats! You can always put on more, if you want to be sure that you are seen. Sew them also on collars, pockets, wherever you see fit 🙂