Google was granted on the 13 December a US patent for a driverless car, titled Transitioning a mixed-mode vehicle to autonomous mode.
The BBC has an intereting story about the features of the invention. The patent was applied for in May and so took only 7 months to get granted, which is amazingly fast (3 or 4 years would be fairly quick). It is a strange field for the company to be working in.
The list of documents in the file wrapper for this patent, from Public PAIRS, shows that on the 5 November Google stated that they were not intending to secure a patent in a foreign country that published applications 18 months from the original filing. This means -- provided that the technology is really new -- that Google has surrendered monopoly rights over the technology in the patent outside the USA.
Anyone looking for similar technology can see the list of 31 patents cited against it as relevant prior art.