You might be interested to click on the previous post before reading this one.
First concern: just as humans can make mistakes, so does any software by freezing and being unresponsive. This automated car will depend on software, and a remote probability of failure is always there. The upside is, even though software might fail, still it would be logical to expect that these errors will be much lower in number when compared with human errors and recklessness.
Second, there would be tremendous amount of privacy violation (of course, most of the buyers would be willing to do that for the benefit they are getting). Your driving records of every minute, your most visited destinations, your favorite streets and highways, your shopping pattern, perhaps information about other riders in your car, your favorite car mechanic, etc. will be in Google’s cloud database (click here to know more about cloud computing). Based on your preference and driving route, you might expect to see customized billboards on your way that are targeted for group of customers having similar preferences and driving routes like yours. You might expect to have a “Google satellite radio” (my guess) that would be broadcasting customized message targeting your car if you pass by a restaurant or a departmental store. At the cost of privacy, as if someone is following you like a shadow everywhere, you would have a lot more enjoyable experience inside a Google car.
Third, even though a very remote possibility, that the system might be attacked by computer viruses and hackers would try to steal and embed codes that might hijack the car to the destination they like. This is scary, but possible.
I strongly believe that, Google knows about all the downsides and would take care of its concerns. Still, the privacy violation would prevail since consumers would be willing to sacrifice privacy in order to get the benefits that Google would be offering.
Here is a surprise interpretation that I would like to offer. Based on all the available evidence, it seems that missing dots are connecting well. Consider the advancement of Google to cloud computing, plus Google+ (strong potential substitute of Facebook), plus Google Car – now it seems like Google wants to be an “Advertising Giant” in such a way that nobody can match. Keep watching Google who would probably define and pave a new way of advertising. Rest of us will learn.