Elon Musk wants to sell self-driving Teslas to the public in a couple of years. Jonathan Gitlin, automotive editor at Ars Technica, said that’s optimistic.

“From other people I spoken to in the industry, I think they would say probably five years away for most situations,” he said.

Gitlin said the technology is advancing rapidly and car makers want a specific kind of regulation.

“If you talk to the car companies,” he said, “Obviously they just want one sort of set of tests they can pass for everybody.”

Gitlin said things aren’t there, yet. Volvo, Google and others are testing different technologies and they want to keep the intellectual property. Another monkey wrench is who’s going to regulate these cars. Will it be the federal government? The states?

Chandra Bhat, director of the Center for Transportation Research at the University of Texas at Austin, said it’s uncharted territory.

“You have multiple entities regulating these things,” he said. “And with self-driving vehicles, it really starts to blur these distinctions.”

Car makers want to make sure self-driving cars are safe, both for the people in them and to protect themselves from lawsuits.