Polarized vehicle headlights.

[Tim Lamb]

Ah. OK

My back up thought is.. how much light would actually get through a polarizing filter from an incandescent source?

[Brian Gaff]

Well there was the fringing interference pattern issues that this sort of thing caused, and of course you are not always sure the null point is going to coincide with the oncoming traffics setting if there is a camber on the road etc. Brian