While the rest of the world is fixated on a future of full autonomous driving, Toyota Research Institute CEO Gill Pratt is urging everyone that it’s more complicated than that and to take things slowly.

Pratt said that “we’re nowhere near close” a level of full autonomous driving, labeled as “Level 5” by the SAE. Pratt, over and over, couched that the company has no idea when we’ll be reaching full autonomous driving. All this came when the company unveiled a new concept car, the Concept-i, at CES today.

“Historically human beings have shown zero tolerance for injury or death caused by flaws in a machine,” Pratt said. “As wonderful as AI is, AI systems are inevitably flawed… We’re not even close to Level 5. It’ll take many years and many more miles, in simulated and real world testing, to achieve the perfection required for level 5 autonomy.”

Of course, that’s not all that surprising. New autonomous driving features like Tesla’s autopilot are designed to operate in more narrow situations and augment the driving experience, but ensure that drivers are still aware of what’s happening around them. In that sense, it helps alert drivers when something dangerous is about to happen and work to avoid that scenario.

But it does echo some oncoming troubles for companies looking to replace drivers with autonomous cars in ways that can support underlying businesses, like Uber. While Uber could get better at defining a narrow scope of situations where it could shuttle passengers around, that it’s going to take a long time to get to more robust autonomous driving means that we might not be losing humans any time soon to ensure that the experience spans the full spectrum of requirements.

That Concept-i, loaded up with technology that learns a driver’s behavior and powered by an AI agent called “Yui,” is designed to engage with the driver and keep them constantly aware of their surroundings. The Toyota Research Institute is working on two tracks of research called Guardian — which basically assists the driver in situations that require quick response — and Chauffeur, which is more on the track toward autonomous driving.

That kind of engagement may be as simple as talking to a version of Yui in the car, just in some way to ensure that the driver isn’t losing focus — or texting or reading when they’re supposed to be aware of our surroundings. As Toyota collects more and more data, however, the company could theoretically better understand hazards and further improve the augmented driving experience.

While manufacturers gun — and they will — toward Level 4 autonomous driving, it’s going to take decades for a significant portion of cars to be working with that kind of technology, Pratt said. At the moment, one of the biggest challenges is to ensure that drivers don’t over-trust existing autonomous systems and get so confident that they start texting and driving, he said.