Elon Musk recently claimed the Tesla Semi will have an even better range than originally advertised, but other than that there haven't been many updates about the electric semi-truck since it was unveiled last year. However, a Tweet posted by Elon Musk shows that Tesla Semi test mules have a unique driving mode. The CEO loves adding references to his favorite movies in Tesla vehicles, and the Semi is no different.

Whereas the Model S and Model X have featured 'Ludicrous' and 'Plaid' modes inspired by the 1988 sci-fi spoof film Spaceballs, the Tesla Semi test mule shown in the Tweet features a 'Mad Max' mode. But while the Ludicrous and Plaid modes affect acceleration, the Semi's Mad Max mode is related to the autopilot system and is listed as one of the available settings. The mode is listed under the category of 'Blind Spot Threshold' and is one of three available modes along with 'Standard' and 'Aggressive.' Musk hasn't explained what these settings do, but Autoblog suggests it could determine how aggressively the truck executes lane changes when Autopilot is enabled.

Specifically, the "Blind Spot Threshold" probably determines how close a car in the next lane can be when the truck changes lanes. Intriguingly, Musk suggested the Mad Max mode may not even be offered in the production model. "Reality is that it will be pretty easy to bully a self-driving car, as it will always yield. Will probably have a manual override that requires continuous press for hardcore lane changes," he said in response to a Twitter user asking if the mode will be available in the production Semi. As well as the Mad Max Autopilot mode, several other setting categories are shown in the photo including "Augmented Vision," which is likely to be a heads-up display.

Autoblog suggests it may also have something to do with the rear-view camera displays that replace the mirrors. Just like augmented reality phone apps, it could overlay information and graphics to help with navigating and manoeuvring.