Four years ago Elon Musk announced all Tesla cars have the hardware needed for full self-driving, so where is it?

Tesla announced on October 19, 2016, that all cars being produced have Full Self-Driving hardware.

Almost four years later, numerous over-the-air software updates have introduced new features. But there has yet to be a complete Full Self-Driving release.

Tesla CEO Elon Musk tweeted this week that some “expert and careful drivers” will get beta of Full Self-Driving on Tuesday.

Musk has repeatedly promised a feature-complete update, but its arrival has been pushed back time and time again. Other players in the autonomous vehicle space have criticized Tesla’s approach, and have even acknowledged their own timelines were overly ambitious as they’ve struggled to solve self-driving.

Watch the video to learn why Tesla’s Full Self-Driving feature is taking so long.