Lightweight, affordable, and...

[arielmoon]

The Down Low Glow folks (and this looks like a little DLG) found that green was the most visible color to drivers.

The Fibre Flare people said the same thing. Makes sense to me....those neon green fire trucks have been shown to be more visible than red ones. Same idea.

http://www.usroads.com/journals/aruj/9702/ru970203.htm

That is what I wanted to know! Thanks!
ETA:
Although the link would indicate that yellow is most visible.

Golden yellow . . . [is] the most easily visible color for both normal and color deficient groups under all testing conditions."