A prediction about the future, 2017 or 2020 or so:
I'll be able to pull out my smartphone and order a self-driving car. It will come to my GPS location and pick me up. In the event that it's a busy street and the car is non-obvious, my phone will alert me that the car has arrived. This is much like ordering a taxi today by phone, with the added advantage that no one can steal it en route. I'll tap my phone on the door to unlock it with NFC. After I ordered it with my smartphone and was waiting for the few minutes for it to come and get me, I entered my destination into the same smartphone app. The car takes off immediately. When I'm done, I tap out with NFC again, and that's it. My account is charged for the trip. It will probably work like most toll and transit passes where they deduct from a small pre-paid balance and it auto-recharges.
In this world, easily-ordered self-driving cars will replace taxis, shared car services and rental car companies. Why go through the hassle of booking a time slot in the shared car and worry about getting it back on time when it's just as cheap to order a self-driving car? Not to mention driving! Driving is so...pedestrian...so 2012.
Self-driving taxi/shared cars like this will finally be the killer app for full electric cars. These self-aware cars will drive themselves home when the battery is low.
They'll also be a death blow to something like 80% of car ownership. It will be pointless for people in big cities to own cars since borrowing one will be effortless and much more economic and efficient. These same fleet companies will offer discount long-term rates for road trips and holidays.
At first a few players will compete with proprietary systems. Some five years after, the marketplace will standardise, and these cars will become an interchangeable commodity. Governments will step in and run them as "public transit." Luxury brands will come in so that elitists don't have to share cars with the rest of us.
Or so I hope. This on the news that California has recently legalised self-driving cars.