Consumer Reports has been testing a Model 3 with this software and just released a somewhat scathing report about its findings. Those using Navigate on Autopilot found that "it doesn't work very well and could create potential safety risks for drivers." Detailed in the report are several examples of how the software actually lags behind the skill set of a human driver.
Testers for CR say the feature "cut off cars without leaving enough space and even passed other cars in ways that violate state laws." Tesla uses rearward facing cameras to detect fast-approaching objects from the rear. However, CR found that the system will often pull out and cut off vehicles moving at a much higher rate of speed. The illegal passing is also a major concern, though. In several instances, Navigate on Autopilot initiated a pass on the right on a two-lane divided highway. It also repeatedly failed to return to the right lane after performing a proper pass on the left. Both of these maneuvers may be common on the road from human drivers today, but neither are proper and could actually land you a ticket depending on where you are in the country. It's doubly shocking once you realize that it's a computer deciding to perform illegal driving maneuvers.
Another area of concern was the merging feature of the software. CR found the system reluctant to merge into heavy traffic. Once it did finally merge, the car would immediately apply the brakes to create space between yourself and the car in front. At that point, you better hope the car directly behind you is paying attention.
A CR tester said this to sum up his feelings about the software: "This isn't a convenience at all. Monitoring the system is much harder than just changing lanes yourself. 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."
Back in April, Tesla said it had just over 500,000 miles of testing data on its auto lane change feature, deeming it safe for public use. The user can take control when necessary, and should be paying attention with their hands on the wheel at all times. Tesla also previously said that lane changes would only be made when a driver's hands were detected on the wheel.