More accurate gas tank readings

Lots of ways to do this. Modern cars monitor fuel flow already, most actually keep track of how much the injectors are flowing. Couple that with a weight sensor on the tank, or another flow sensor in the neck of the tank and you'd know exactly how much fuel you had. Heck just a weight sensor on the tank would get you closer.

But I'm not sure I understand the point. So you can literally run the tank down to the absolute drop of fuel? People would still run out of gas, thinking that last couple of drops would get them to the gas station. It would just make them even more irritable if they got caught at a light, knowing they only had 3 ounces of fuel in the tank.

I have a pretty good idea of exactly how low I can run my tank, and I still almost always fill up at a 1/4 tank. No worries that way. Once you've put a couple tanks of gas in a car, you should have a decent idea of how the gauge works.