Tesla Motors co-founder and CEO Elon Musk thinks that human-driven cars could eventually be outlawed as computers show they can do a more efficient and safer job of driving.

“In the distant future, [legislators] may outlaw driven cars because they’re too dangerous,” Musk told a group in San Jose on Tuesday at the annual conference of technology firm NVidia, which develops technology for self-driving vehicles.

Musk’s comments were reported on the NVidia company blog. He was being interviewed by Jen-Hsun Huang, NVidia co-founder and CEO. Musk later clarified via Twitter that he does not favor outlawing humans driving and was just pointing out that such laws are a possibility.

At the conference, he said autonomous vehicle technology is advancing to where self-driving cars will be taken for granted soon. “We know what to do, and we’ll be there in a few years,” he said.

The transition from humans to robots behind the wheel will take some time, Musk said. There are still issues to be worked out getting autonomous cars to cooperate in urban and suburban settings (as opposed to on highways where they already do well). Also, he predicts there will be some regulatory resistance initially, until self-driving cars prove themselves. Plus, there are two billion cars on the road and 100 million more being manufactured each year. He said even if self-driving cars were suddenly available tomorrow, it would take 20 years to replace the existing fleet.

So the move away from people won’t occur immediately, but it will happen. Why?

“It’s too dangerous,” Musk said. “You can’t have a person driving a two-ton death machine.”

Musk, who helped start PayPal, is also co-founder and CEO of Space X and has promoted a high-speed transportation system called Hyperloop in which humans would travel through tubes.

Tesla has been adding self-driving features to its own cars.

Following the conference, apparently wanting to reassure humans he is on their side, Musk took to Twitter to comment: