So my newest follower, Pawl Bearing, says we could replace windshield wipers with something more efficient. Okay. But first, the history.
The first cars ever produced were produced as extensions of the horse-pulled buggy that was the prime long-distance transportation of the day. It had an open top, like modern sports cars, and you could really feel the wind in your face. And the bugs in your teeth. And occasionally something flew into your eye. The manufacturer suggested wearing goggles while driving. I'm not entirely sure what you were expected to do in the event of rain.
So some bright automotive engineer, the Pawl Bearing of his day, gets the idea to enclose the cabin, with glass windows for visibility. That annoying wind went away, unless you specifically asked for it by rolling down the windows. And the windshield was the front-window that allowed you to see where you were going minus all the bugs in your eyes and teeth. It worked well....unless it got wet. You'd have to stop regularly and towel it back off. Annoying.
A cotton towel would obviously do no good, as it would rapidly saturate within the first few minutes of a rain storm, but there was an existing technology, the squeegee, a thin strip of rubber that could endlessly wipe the water off a glass surface. You've probably used one at a gas station to clean your windows. One was mounted on a motorized arm, and voila, the modern windshield wiper. Then it was doubled up, so it could cover the entire windshield.
My first idea of what to do instead comes from my own history of car ownership. My first car was a station wagon, which had a trunk accessible from the back seat, and a wiper on the back window. I now drive a non-station-wagon compact car, and one of the features I miss is that back wiper. Instead, I have a series of wires running through the window. It's made as an anti-frost feature, as running electricity through the wires heats the window, melting any ice accumulated on it. I note in raining weather that it's very effective at keeping the window clear. I'm going to reject this as inefficient, however, because it's less effective than a wiper and uses more power.
No, I think the best technique would be to replace the entire windshield with a large monitor, which shows a composite footage from a number of cameras. As visual recognition technology improves, this overlay could give me the heads-up on things that may be a problem on the road. This can be mounted behind a much tougher surface, making damaged windshields a thing of the past. The cameras would be very small, and specially waterproofed.
The camera system had better be massively redundant in that case, because the loss of even a third of the cameras would be catastrophic.
Alternatively, we could replace the glass with something that somehow retains visibility no matter how wet it gets, but this is an unlikely development in materials science.