According to SAE International, there are six “Levels” of Automation ranging from No Automation (Level 0) to Full Automation (Level 5). The United States Department of Transportation adopted these guidelines in September 2016.

Tesla’s Autopilot is currently at Level 2 — albeit somewhat more sophisticated than the guidelines that describe that level. When asked as to whether or not hardware or software is the issue holding back Tesla from full automation, Elon Musk said that the hardware necessary to make his vehicles fully autonomous currently exists, it’s a “question of the software.”

In December 2015, Musk said that a fully autonomous vehicle “with the probability of an accident is less than that of person” is less than two years away.

Once the technology is available, Musk estimates that it will take another one to five years to get to vehicle to pass regulations for commercial availability.