FILE- In this Sept. 25, 2012, file photo, California Gov. Edmund G Brown Jr., front left, rides in a driverless car to a ceremony in Mountain View, Calif., for the signing of a bill allowing for testing of driverless vehicles in the state. On Friday, Dec. 27, 2013, Michigan Gov. Rick Snyder signed two bills allowing similar testing in Michigan. The Michigan laws permit operating driverless vehicles on state roads, as long as a human driver is in the vehicle as a safety backup. The measures also provide partial shielding of manufacturers from liability suits. (AP Photo/Eric Risberg, File)