Three years ago, Google's self-driving car project abruptly shifted from designing a vehicle that would drive autonomously most of the time while occasionally requiring human oversight, to a slow-speed robot without a brake pedal, accelerator or steering wheel. In other words, human driving was no longer permitted. The company made the decision after giving self-driving cars to Google employees for their work commutes in San Francisco and recording what the passengers did while the autonomous system did the driving. In-car cameras recorded employees climbing into the back seat, climbing out of an open car window, and even smooching while the car was in motion, according to two former Google engineers. "We saw stuff that made us a little nervous," Chris Urmson, a roboticist who was then head of the project, said at the time.