Richard Waters and Andy Sharman:

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“There’s a lot of really cool stuff, no doubt,” he said, listing Audi, BMW, Mercedes, Ford and General Motors as companies that have made headway. But he also called it “flawed” to see driver-assisted technology as a necessary point on the path to what Google has in mind: a fully autonomous car.

“The idea that it’s just a continuum, it’s not clear that it’s going to play out that way,” he said. “There actually is a discrete step when responsibility shifts from the driver to the . . . self-driving system.”

Google’s gamble that it can make the leap straight to full autonomous vehicles comes as Wall Street has become increasingly wary of the company’s expensive long-term bets. In a sign that it was starting to pay heed to investors’ concerns, a company executive last month said that a rethink of Glass, the company’s controversial smart-glasses project, showed that Google is prepared to draw in its horns when teams cannot hit their targets.

Mr Urmson will not discuss how much Google is spending on driverless cars or what internal milestones he has set. But he is bullish about the company’s chances of reaching its goal.

One yardstick is economic. The costs of the sensors embedded in the vehicle have fallen steadily, he said, including for the laser-controlled sensors that sit on top of the vehicles and initially cost $75,000 each. “We’re in no doubt, mounting a $75,000 laser on the roof isn’t the path to production,” he says.