Originally Posted by Dchiefransom
The driver might not have seen the cyclist he hit, who was on the right. I think Sheldon Brown's website has an article of his on why reflectors are nowhere near as good as lights, and why reflectors can only be seen from certain angles.
I've been driving cars for a long time and I have never had a problem seeing reflectors next to the road facing toward me. This is a primary geometry for reflector road markers and reflective paint on signs. Barring dense fog, the reflector would have been visible.