The car steps in to take over when it needs to.
This is one of the less dramatic automatic emergency braking saves, but it's a save nonetheless.
It appears as though perhaps the driver is a bit inattentive at the will as he admits the Tesla stopped itself to prevent a crash. However, the video appears to show a situation in which an attentive driver could've stopped the car in time.
Regardless, it's Tesla technology to the rescue once again. Both Autopilot and automatic emergency braking remain at the ready even if Autopilot isn't activated. This means that the systems are always ready to take over if the situation arises.
Watch this video showing how automatic emergency braking brings a Tesla Model 3 to a stop to prevent a crash. And yes, all cars should be equipped with a system such as this as standard equipment. Safety is paramount.
Video description via M Nair on YouTube:
Happened on 101 South in Downtown LA this afternoon (May 19, 2019)