Idea for car head lights - why doesn't this already exist?

Hahahahaha awesome, I completely didn't even think about those. Though I don't think they exist in the plural zones of the galaxy...

In reply to sporqster: Yours is almost exactly like my idea, I came up with it too, and apparently my dad's dad did too!, the only difference being the orientation of the film on the windshield and headlights, yours being vertical or horizontal on the windshield with the film on the headlights being perpendicular. My idea was to have the both of the films in the same plane, (or some deviation thereof for the windshield tint which would facilitate personalized dimness or brightness of the approaching headlights) with the headlight film being standardized right or left 45 degrees with respect to the ground. Sitting in your vehicle facing forward, from your perspective, both the plane of polarization of your headlights, and your windshield tint would be 45 degrees, say, to the right with respect to the ground, but oncoming headlights would be polarized 45 degrees to the left, effectively blocking nearly all light from the approaching car. The reflected light from your headlights, being polarized in the same plane as the film in your windshield would remain unaffected. My idea works exactly the same as yours when oncoming traffic doesn't have a polarized lens on their headlight, and even better if the other driver has polarized film (standardized, polarized 45 deg. to the right or left.) Like you and most everyone I suppose, I HATE those glaring, blinding oncoming headlights!

Forgive my ignorance on the polarization of light but... I know the light can be polarized when leaving the headlights, but does it remain at the same polarization when it is reflected back off the environment? I imagine textured surfaces diffusing the light, and I think that most retro-reflective surfaces (signs, road paint) have an element of polarization to their reflection.

Am I missing something by asking about photochromatic filters like in welding helmets?

Can't one produce a windshield-sized welding lens but adjust sensitivity to real-time ambient light conditions?

Zombie thread, canoe deleted