After the departure of Chris Urmson from the project, Google has hired Airbnb executive Shaun Stewart as a director for its autonomous vehicle group.Stewart had previously been head of vacation rentals at AirBnB and before that worked for a division of TripAdvisor.The website TechCrunch calls the appointment a "good fit", because his expertise revolves around short-term travel rentals and getting services off the ground, which it adds is important when the concept of a driverless taxi is still brand new with details that need to be pinned down in the years ahead.