I have decided to go back and finish college now that I'm in my thirties. The plan is to commute the 5 miles to campus via bicycle along some relatively busy roads, and as such, I have been looking at safety/visibility as an important factor. My bicycle already has all the standard bells and whistles: front/back/wheel reflectors, bell, handlebar mirror, headlight, flashy red taillight, etc... and while this is of some comfort, I frequently pass bicyclists under marginal lighting conditions, and all of these features don't make the rider stand out to me with the possible exception of the flashing red taillight (a very small and dim deal more often than not).
So.... I went to the store to find some solutions. There are full blown reflective vests (tacky, uncomfortable, covered by my backpack, an extra item that I need to keep track of), more dim little headlights (how many would I need to strap on my handlebars to feel safe from being hit from behind or the side?), very expensive reflective tape (which, when slathered on the frame of my stupid expensive bicycle, would be obscured by my legs and/or wheels half the time), some random LED doohickies that get strapped around backpacks or waists or whatever (an OK idea, but batteries wear out and it's something extra to keep track of, and it cost $20, and I'm not convinced it's that visible anyway...) And then... in the automotive department, THE ANSWER.
Step 1: Materials and Tools
Time: 1 hour or less
Cost: $10 US
Tools: something pointy to poke holes (a small screwdriver would work fine)
automotive reflectors (the ones I got were $1.94 for a pair at Walmart. I got two sets of red and two sets of yellow.)
some zip ties or fishing line or wire or string or whatever
the backpack you intend to stick your thousand dollars of textbooks inside while commuting to your Organic Chem class
Step 2: The Making Bit
Step 1: put on your backpack and get on your bike. Figure out which part of your backpack faces directly ahead and which part faces directly back while you are in your favorite cruising position.
Step 2: carefully poke a few holes and ziptie the reflectors onto your backpack. A slightly blunt pointy thing can be wiggled through the fabric without breaking threads if you are careful. Leave the ties loose on your shoulder set because they need to be able to pull away from the strap where it curves over your shoulder.
Step 3: add some yellow reflectors to your shoulders, some red ones to your rump, some yellow ones on the sides, and stick that last pair of red ones onto the sides of your helmet if they look like they'll fit.
Step 3: The Results:
What I have now.... a backpack that has some large reflectors facing forward/backwards/sideways which should be MUCH more visible than the reflectors my bike has (and it's less likely that someone will "mistakenly" pick up my bag thinking it's theirs). I avoided messing with my bike. I don't have anything extra sitting around to misplace or forget to use. No batteries or buttons to mess with. And I get to be "that guy with the trailer reflectors" around campus.
Hope this gives you some ideas on how to improve your visibility for just a few dollars while out in the world.