If you are overly concerned about avoiding cars via seeing their headlights perhaps you should try driving on the other side of the road, it's safer over there.
Curvy roads, and lack of light pollution in the sky, combined with probable sleep deprivation doesn't make for a good situation. Even if you stay on your side of the road, who says that other guy coming in your direction is doing as well?
Headlights in your face are not a very good way to keep track of traffic, neither is a complete absence of light where a car should be though. An optimal solution would probably be something that prevented getting blinded by oncoming headlights while still retaining enough visual cue to be able to perceive that a car is headed towards you and to track its position.
You could just dim the glare points so they aren't glary anymore, but you could still see the light sources. My car has an auto-dimming rear view mirror, which works very well. This dims the lights so you don't get glare (much of the glare at night is from cars behind) but you can still see the lights without problem. It's so natural you don't notice it happening. The same principle could be used.
I would see it as a thin film applied to the inside of the windscreen, or possibly some type of HUD optics.
Car makers can already track eyes, because the latest research is in tracking blink rates to detect fatigue.
I'd say this tech is feasible just needs the different disciplines brought together to make it work.
You can judge distance from individual, over-bright dots? It's a well-known extremely difficult task for humans.
You have no size to compare, because the glow is larger than the headlight itself. You have large distances, so your parallax is minimal, and isn't very accurate anyway. It's dark, so on highways you frequently don't have any known references to compare against (like road width or car size). The closest you get is the distance between headlights and occlusion, which is unknown on any random vehicle and on more widely-spaced vehicles.
When you drive in the dark, if there is no ambient lighting, all you can generally see of a car approaching or behind is its lights, and you can definitely judge distance from that. This is noticeable particularly on motorways - it's very hard when you start to drive but becomes quite natural after a time.
