In 2018, Audi will deploy a small fleet of cars to see how its piloted parking technology interacts with a garage designed specifically for autonomous cars. With no one getting in and out of the cars, the space needed for each vehicle is reduced by 21 square feet. You need just four inches of space between mirrors on neighboring cars, since they will park themselves with machine-like precision (because they’re machines). No elevators or stairs or pedestrian pathways are needed, either. Audi estimates such a lot could pack 60 percent more vehicles than a conventional garage of the same size. Audi’s not alone here. Uber is working with Carnegie Mellon University to test self-driving cars in Pittsburgh.