Last week, Tesla released an early version of its long-awaited “full self-driving” software to a limited number of customers. It was arguably Tesla’s biggest Autopilot update ever. The software enables Tesla vehicles to autonomously navigate the vast majority of common roadway situations and complete many trips from start to finish.

Tesla considers it to be beta software and says it’s not intended for fully autonomous operation. Drivers are expected to keep their eyes on the road and hands on the wheel at all times.

To understand the new software, I watched more than three hours of driving footage from three Tesla owners who got the FSD update. These YouTube videos underscored how important it is for drivers to actively supervise Tesla’s new software. Over the course of three hours, the drivers took control more than a dozen times, including at least two cases when the car seemed to be on the verge of crashing into another vehicle.