Alternative Methods

Excellent, very detailed analysis from 2001. This is not a new problem, although it is worsening with more intense headlights.

HeadlightGlare.pdf

Dynamic Scattering Mode

I wonder if I could get a film as a final form? Here's a good video explaining some of the failure modes of it. https://www.youtube.com/watch?v=OHsYb7c6rys

Attachment to sun visor

Could be attached with velcro, opaque thing. However, requires user to flip it down and up constantly, which is not great. Feels claustrophobic. Also blocks vision of rest of road on left side.

Other ways that don't work

I saw a patent for red light?! Adding light doesn't help..., although reducing blue light with a yellow filter helps a little.