I think artificial intelligence is going to have a huge impact on transportation (and everything) in the next few decades.
My guesstimate for time-frames are
1) Early 2020s: First fully automated computer-driven cars.
2) Early 2030s: Virtually all new cars are computer-driven.
3) Early 2040s: All vehicles on the road are computer-driven.
I see these events as having profound impacts. I'll skip all the way to the early 2040s, when I expect all vehicles on roads to be computer-driven. Here are some impacts I see:
1) Individual ownership of vehicles will be virtually eliminated. Most people in 2013 have cars that sit unused for over 20 hours per day. This is a complete waste of money, because depreciation is occuring, and taxes and insurance are being paid, even though the car is sitting unused.
2) People will obtain cars like we now get airline tickets, except the cars will often be ordered hours or even minutes in advance, rather than months or weeks in advance.One will state one's destination and time of departure into a smart phone or personal assistant, and options will come up, with different prices and different arrival times. Non-stop short arrival times will be more expensive, and multi-stop trips with long arrival times will be less expensive. Also, fancier and less-fuel-efficient cars will be more expensive, and plainer, more-fuel-efficienct cars will be less expensive. The car will take you from the door at one location, to the door at the other location. No parking in parking lots.
3) Accidents will be virtually eliminated, so insurance will be minimal, and paid for by the fleet owners.
4) Many cars will become incredibly small. Even Smart Cars and Cooper Minis have room for two passengers. In the 2040s, single-seat cars will be extremely common. They will likely be powered by batteries, rather than gasoline. This is because there will be no need for "range anxiety". That is, no car will come to you unless it knows it has enough battery life to get you to your destination and then to a charging station.
5) An intercity-trip (say Durham, NC to Charlotte, NC...a distance of about 150 miles) might involve getting into one car, then changing to minibus or large bus (or train), for the trip between a particular point in Durham and a particular point in Charlotte. Then there might be another switch to a car in Charlotte. The delay in these two changes of vehicles would be more than compensated for (compared to the current situation) by the fact that travel between Durham and Charlotte would be at well over 100 mph. The total time, door-to-door, would probably be under 2 hours.
6) Transportation will be much more electrified. Virtually all short-range trips will be by battery-power. Total U.S. gasoline usage would cut by more than half.
7) Parking lots would be eliminated. No parking lots at football and baseball stadiums. No parking lots at malls (which might not exist anyway). No parking lots at businesses.
8) Traffic congestion would be completely eliminated. Instead of traffic lights or stop signs, cars at intersections would simply pass within feet of one another at right angles, at full speed, because the computer controls between the cars would communicate which car crossed first. Speeds on freeways, even within cities, would be 70+ mph, at all times. Cars and buses would travel at these speeds within feet of one another.
9) Big-box stores like Walmart and Target would be eliminated. Grocery stores would be eliminated. Instead of going to the store, one would shop at a virtual store (on one's 80 inch organic light emitting diode TV), order what one wanted, and have it delivered by an automatic vehicle (which would coordinate with all other customer deliveries).
10) Home garages and commercial parking decks will be eliminated. Home garages will be converted to living space.
11) The total number of vehicles will be greatly reduced, because many vehicles will be running almost continuously (except when charging batteries). The number of mechanics will also be significantly reduced, because cars will run continuously, and get maintenance at more regular intervals.
It's going to be quite a change. (Hope I'm around to see it.)