If you come across any driverless Volvos towing trailers and caravans through the mountain passes of Death Valley in California, don't panic. It is simply Volvo testing and refining their towing capacity
Volvo developed a robot to automate the driving and minimize subjectivity. The device resembles a cross between cruise control and Stanford's Volkswagen interface. It steers and maneuvers the car thru several tests, including movements meant to destabilize the trailer.
Looking at the photographs, it appears that a person is still in the driver's seat. Presumably, this fellow provides navigation and manual override. This is no DARPA entrant, yet Volvo's device is impressive nonetheless.