This invisibility factor is very serious.

And then there are the things that riders do to themselves to make it worse- turning the headlight off, wearing all black, reducing the size of the taillight for decorative reasons, etc.

I followed a Harley rider down a mountain canyon road in the dark one time. I kept closing up on him waay too much even though I was very, very attentive and careful. I realized that the reason was that he was showing a single tiny taillight and otherwise he was entirely blacked out. I had insufficient information to work with to not overrun him.

From that I immediately ordered a Conspicuity Inc. See-Me vest. The retro-reflective material used for the stripes is positively astounding. Anybody around me WILL have sufficient visual information to see me. They still might not process it but "I didn't see him" won't stand in court.

The hunter orange vest with super reflecting chicken-yellow stripes has made a huge difference. I wouldn't ride without it.