Google has been using what many consider to be economy cars for its autonomous vehicle fleet. The autonomous vehicle we've seen most from Google has been a Toyota Prius. Google has apparently now added something more luxurious to its autonomous fleet with the addition of a Lexus RX450h hybrid SUV.
Some reports say that the sensors on top of the Lexus are more compact. Other than a different design to fit the top of the SUV for the holding support, the sensors look the same as the Prius to me. The Lexus was spied testing in Southern California.
You can't tell from the photo if the vehicle was being driven by a human or was operating autonomously. I would assume a person was behind the wheel since California is still working on safety standards and performance requirements for autonomous vehicle testing and operation within the state.