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"We are going to need a lot of help in the next stage of our project," he said at the annual Automotive News conference in Detroit. "We're going to be partnering more and more and more - you can count on it."
Google was reportedly going to sign a deal with Ford late last year, but it never materialised. Meanwhile, General Motors, one of the largest car manufacturers in the US, invested over $500 million (£346 million) in Lyft, a ride-hailing app, to help build self-driving cars.
"Automakers have a track record of producing cars at scale," said Krafcik. "As work progresses, we look forward to working with many of you people as we bring this technology to market."
Krafcik said there was a lot of "inbound interest" in what Google was doing. "Every [car maker] has been wanting to speak to us," he said.
Google's self-driving cars have racked up over 1.3 million miles on roads since September 2014, with far fewer crashes than regular, human-driven cars.
Analysts for Pacific Crest, a research firm, calculate that the self-driving car project is worth around $8 billion (£5.5 billion) to Alphabet, the parent company of Google.