Tesla says it has improved its self-driving Navigate on Autopilot system with its latest software update. Consumer Reports begs to differ.

Last month, Tesla updated its Navigate on Autopilot software to allow its cars to change lanes automatically, without prompting or warning the driver. This gives the system the ability, for example, to navigate highway interchanges by choosing the appropriate lane. The system fulfills Tesla CEO Elon Musk's promise to develop a system that can drive itself from highway on-ramps to off-ramps without intervention (though several system warnings note that the driver still has to pay attention, and it will shut off if the driver doesn't hold the steering wheel for too long.) 

Only, Consumer Reports says that the system does a poor job changing lanes and that watching over the system and correcting its mistakes is more work for drivers than just driving themselves.

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"The system’s role should be to help the driver, but the way this technology is deployed, it’s the other way around,” says Jake Fisher, CR's senior director of auto testing. "This isn’t a convenience at all,” he says. "Using the system is like monitoring a kid behind the wheel for the very first time. As any parent knows, it’s far more convenient and less stressful to simply drive yourself.”

The magazine got the update on its 2018 Model 3 test car last month and took to some local Connecticut highways, where its test track is based, to try out the new system.

"In practice," CR says in a blog post, "we found that the system lagged far behind a human driver's skill set."

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In CR's tests, the organization noted, Navigate on Autopilot was "incredibly nearsighted." It didn't seem to react to brake lights and turn signals, and frequently cut off other cars. Worse, when trying to merge, the system would be tentative at first, then, after creeping into an adjacent lane, the car would brake to create space ahead for itself, likely startling other drivers behind.

When it moved out to pass other cars, the Tesla didn't return to its lane.

The car also routinely passed others on the right when that's where a gap existed, which is not legal in the state.

Consumer Reports Tesla Model 3 Navigate on Autopilot ready for right-lane pass

Consumer Reports Tesla Model 3 Navigate on Autopilot ready for right-lane pass

Several CR test drivers on various highways encountered similar problems.

It's worth noting that when the organization first tested Navigate on Autopilot last November on its Model S, it found the same problems, among others, and Musk later said the company would update the system to return to its original lane after a pass. The update Consumer Reports received didn't seem to include that ability. 

Before the latest update, Navigate on Autopilot wouldn't change lanes on its own, but would alert drivers when a lane change would be beneficial, and the driver would have to approve it (except in some cases, like moving into exit ramps). The new system automatically changes lanes, but drivers can override the system using the turn signal stalk or the steering wheel, which CR said its drivers did most of the time. The automatic lane changes can also be disabled in the car's menu.

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Consumer Reports' vice president of advocacy, David Friedman, is the former acting administrator of NHTSA under the Obama administration. He said, "Tesla is showing what not to do on the path toward self-driving cars: release increasingly automated driving systems that aren’t vetted properly. Before selling these systems, automakers should be required to give the public validated evidence of that system’s safety—backed by rigorous simulations, track testing, and the use of safety drivers in real-world conditions."

Last month, Tesla hosted investors at an event at its Fremont factory to promote its new generation of Full Self-Driving hardware, where Musk said the company plans to have the Full Self-Driving Capability "feature complete" in a year and would offer drivers the future ability to turn their cars into revenue-generating self-driving robo-taxis as soon as federal regulations allow it, perhaps another year or two after that, Musk said.

If Consumer Reports tests are any indication, the timeline could take longer than that.