Actually, several manufacturers have self-driving car projects[1]. some of them are even field-testing them in real-life situations, such as a driven leader truck being followed by other trucks[2].

So, I don't think it lacks competition for Google, who doesn't even build their cars - most probably they'll license the technology for other companies, and Tesla may well be one of them.

[1] Links from 8 to 14 in this Wikipedia page: http://en.wikipedia.org/wiki/Autonomous_car#cite_note-idsia-...

[2] http://phys.org/news/2013-03-japan-group-fuel-saving-driverl...