For those of us who ride at night, or even may get caught off guard riding in the evening.
Buy a couple or more of those neon glow sticks. You can get em cheap for a dollar at some places. Place inside your saddlebags, purse, back pack or whatever you use for storage on your bike.
They will last forever till you need them and, at least give others approaching you if along side the road, notice that your there.
They come in different colors and again an inexpensive item that takes up very little space and not a heavy object either.

kim