Take an autonomous car, make it safer than with a human driver, make it callable upon demand. When a car can drive itself to your house, take you where you want to go, and then move on to the next ride, you might decide to now own a car anymore.
Make the cars electric, with automated charging stations, and you get a robotic transportation system that requires fewer vehicles, fewer emissions, fewer accidents, and very little human interaction. Cabbies beware.
Economics suggest this works best in dense populations and in places where moving people and small packages are the majority of trips. Pickup trucks will still be needed at construction sites, SUVs on unimproved roads, and motorcycles for individual autonomy. And some folks will just want to have a car to have a car.