I have family members and friends who are marathon runners and bicyclists.  They practice every chance they get even if it includes training during nightfall.  Precautions are best taken for safety purposes and I can easily recall people wearing bulky reflectors or even carrying a flashlight.  Fashion designer and technologist, Pauline van Dongen, is a runner herself and has come up with an ingenious shirt top for these health-driven night owls.  The Phototrope shirt has a jersey shell with pieces of reflective foil placed over LED lights.  Just access the battery inside the pocket and turn your garment on or off.  Pauline’s prototype is 100% washable.  She is already working on a newer version of the Phototrope that would allow for the LEDs to react to movement.