Some people think I'm being too obvious but I'm mostly just throwing the idea out of using reflective material. I, myself, have been hit and been very close to have been hit while riding at night. I ride every day and the nights where I live start at about 5. I use reflective tape and I also use lights while riding my bike. Now, back to the instructable!
This is a great idea if you ride in the morning or evening. The last thing you want is someone to rear-end your bike! So get some reflective material on your bike or helmet so people will see you on the road.