Autopilot currently checks for driver attention solely through the steering wheel, sending a warning (and if necessary, stopping the car) if you take your hands away for 24 seconds. Super Cruise, however, uses a camera to track your gaze and will deliver a warning if you look away for just four seconds. This not only ensures that you're actually focused on the drive, but could prevent incidents that might happen with only a brief lapse in concentration. Cadillac's system was also clearest about when drivers could use it.

CR tested Nissan's ProPilot Assist and Volvo's Pilot Assist, but found that they had trouble with undulating roads and keeping to their lanes (in Nissan's case, that's on purpose to keep you engaged). Volvo's system won't brake if you ignore the warnings, and it won't steer if you haven't already activated the lane-keeping feature.

In a response to the rankings, Tesla told CR that there was a camera in the Model 3 cabin that wasn't being used to monitor drivers, but might be used with a future software update. It's also important to note that Super Cruise has its limits. It can only work on GM-approved highways, for instance, where Autopilot is more generalized. All the same, the rankings are a reminder that semi-autonomous driving features are still young, and that a tech-focused company like Tesla isn't guaranteed to dominate.