A brand new shiny underground parking lot has recently opened in central Tel Aviv under the refurbished Habima theater. It uses small lights to indicate whether a spot is available or not. A great idea. The image below (thank you Eric Nakamura) shows the effect (not the specific lot I am talking about).
But how can you make it even better? Get rid of the red lights. It's information you do not need. Green lights only to mark the free spots, and the parking lot will look a lot calmer.