I think jellicle is right, that this invention can cause just as much harm as good.
When intelligent people make decisions, they consider the worst and best possible outcomes.
Add to this that the public will probably be incentivized to tax or otherwise limit car owners, and the value proposition gets even worse. It could turn out waiting for an automated vehicle from a network to arrive is still faster door-to-door, since it may have privileged access to high-speed roads or lanes that owned vehicles may not, due to regulation a la HOV, etc.
edit: Also I don't disagree that in the early adopter phase autonomous cars may introduce inefficiencies. But the autonomous car is a 100, or even 1000 year invention, not a 10 year one. In many ways it may just be a single one-time event, when ground-based personal transportation for a civilization becomes automated, so it may have no shelf life at all.
Because they won't most of the time? Let's say that during peak rush hour, N people + M packages need to be transported. That means that in order to satisfy peak demand efficiently, we need N+M cars and road capacity. During off-peak hours, lets say that only 20% of the population needs to travel. That means you've got the other 80% of the cars sitting around doing nothing just like they are today. If the average distance to nearby parking is say 2 miles, then we have 80% of the cars just driving empty 2 extra miles to prevent themselves from taking up road capacity (while today we trade off by creating parking lots).
Despite that, I do think there will be some improvement in terms of car use. Namely:
* the average car size will shrink to probably that of a smart car (2 seats, little cargo room) * parking lots will shrink (but not disappear) due to effective stacked parking * vehicle efficiency will increase (human drivers are inherently bad at maintaining fuel/energy efficiency with acceleration/deceleration)
The danger is that this once again will make car use "cheap" and like the article suggests, extends sprawl yet again. So we'll just have another half a century of poor land use just it might be slightly more efficient this time around.
On your point about sprawl, I can just as easily envision the opposite happening. As car ownership becomes less of a necessity, I do not need to worry about a garage or parking when considering where to live. Additionally, I don't think that autonomous vehicles will necessarily make car use cheap, I think more realistically, the marginal cost of driving (i.e. cost per mile) will still be a non-insignificant amount, but the convenience will increase dramatically (especially for people who do not own cars), but I imagine commuting an hour to work each way using an autonomous taxi service will still cost you a pretty penny (partly due to the demand issues mentioned above). Also, long commutes still suck, even if you aren't driving the car. I participated in carpool for a year (one hour each way, my car was too crappy, so I never drove, just pitched in for gas), and I was able to get some work or reading done, but I still hated it.