Among those taken off guard are various state regulators who now have to address the idea of having a small fleet of test vehicles rolling around that will have no steering wheels, pedals or any other controls a human driver could use.
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Nevada, Florida, California and Michigan have approved driverless, or officially, autonomous vehicles. California, where Google is based, is in the preliminary stages of writing its guidelines for driverless prototypes, which go into effect in September. But they currently "require that a human being be in the vehicle as a test driver," explained Bernard Soriano, deputy director of the California Department of Motor Vehicles. "Someone…ready, willing and able to take over should something go wrong."
That could cause a problem for Google if the only thing someone in the little prototypes can do is hit a button to bring a test vehicle to a stop.
"Google is going to have to manufacture those vehicles with steering wheels and pedals," Soriano emphasized.
That's not entirely a conflict with the Silicon Valley firm's plans, at least not initially.
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Looking like a cross between an old Volkswagen Beetle and a Smart Fortwo microcar, the first of the battery-powered self-driving prototypes will have conventional controls, Chris Umson, director of Google's Autonomous Vehicle project told NBCNews.
"Safety is critical," he said during an interview, adding that "the nut isn't cracked all the way," and that a lot of work remains to be done before the company is confident the prototypes will be able to wander public roads with just a computer in control. But the goal is to eliminate traditional controls from the vast majority of the prototype fleet. And that could pose a serious regulatory challenge.