Gave me an idea of dynamic pricing for public parking, like the surge prices of ride sharing services. Maybe this already exists somewhere?

If there are only a handful spots left, the price would be really high. If a parking lot is not that popular it will automatically be cheaper. Environmentally friendly cars could get a discount.

Instead of reserved parking spots, the spot would know for instance if it's never used during working hours and the prices would adjust to optimize the fill rate of all spots. Residents would get a discount for spots close to home.

I guess most cities have zones with different fees, and often free parking on weekends and nights. This would instead adjust it automatically, maybe even adjust for popularity of a particular group of spots.