Specifically, every car should be mandated to have +40° clockwize angle from horizontal polarized filter. They must also have the same filter on the headlights. Any light from the car will be in phase with the windshield, and visible.

Now whenever a car is coming towards you with the same setup, the light will be 80° out of phase. Still visible but super dim, and people can rock their super bright highbeams all night without blinding other drivers. Any signs that drivers need to see can be phased properly to enter the polarized window, but you will not have as much light pollution because they can be tuned.