This video clip shows a distracted driver who dumbly crashes into the rear of a stopped car. This could've been easily avoided had the car been equipped with some accident prevention systems.
Though Autopilot doesn't always perform perfectly, this type of rear-ending is an easy one to avoid for Tesla's system.
We assume (or rather it should be clear from the video) that the driver in the car that does the rear-ending had taken his/her eyes off the road for a second and had assumed traffic would continue accelerating. That assumption was wrong though and once the driver attempted to react, it was far too late.
Watch the TeslaCam video clip to see why your eyes should always be on the road.
Video description via idog63 on YouTube:
TeslaCam Rear-Ender Accident Sacramento 7/25/19
West bound on Richards Blvd