[__MatrixMan__]

I've never seen head tracking applications at all, and I'm not surprised that they're underwhelming, but I hope the state of practice gets better because it would be really cool to have an AR setup where metadata is projected onto the windshield and windows such that it lines up with the driver's perspective.

Imagine a thousand foot tall semi-transparent google maps pin, resting lightly on the head of the person you're picking up, visible for hundreds of miles but only to those who are interested.

[catalogia]

The sci-fi tech I've wanted for years is a liquid crystal windshield that blacks out a small circle over the sun from the driver's perspective while leaving the rest of the windshield clear. Driving west in the evening or east in the morning, I wager a lot of people have had this idea at some point.

I have no idea if it will ever become feasible, but I sure hope it does.

[astatine]

This. Not just the sun, but more annoyingly, opposing headlights in the night. Technologies to avoid blinding opposing drivers are not adequate. We could do with technology to assist those who are on the affected side.

[xaedes]

Material sciences could bring a solution:

Transparent material that becomes opaque to bright light (something like gamma < 1, gain < 1) in the direction of the light. So each point of the material is transparent or opaque depending on the viewing angle and respective directed light flow through it.

I think such a material could be engineered.

[FPGAhacker]

I've had the exact same thought. I expect it to happen eventually, or some other tech will render the issue moot.