system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How is my brain able to go into this zoned-out "auto-pilot" state while I'm driving, yet I get to my destination safety with no real recollection of the trip?

I'm obviously not veering all over the place or putting anyone else in danger. It's like my brain goes into it's own cruise control. What is actually going on when this happens?
gpt
Psychologist here. This happens for essentially the same reason that you Can "zone out" while you're walking around, not stumbling or colliding with things. These tasks are called "steriotypic repetitious movements" and they are actually controlled by a different part of the brain after you've fully learned the skill! When you start to learn any skill, like riding a bike, your cortex is the part of the brain doing the work of figuring out how to coordinate your muscles appropriately. Its complicated at first, and it involves your full attention, just like when you learned to walk. However, over time your cortex figures out exactly which muscles need to coordinate in exactly the right way, and it basically "saves" that motion in memory. When you go to do that action again after its already been learned (or saved) a cool thing happens, the cortex isn't nearly as involved anymore, now it's more subcortical  (aka below the cortex, so deeper in the brain) regions that control the movement. The result? Now you perform an action while your cortex is free to think (or not think and "zone out") and forget you're actually doing anything complicated at all. 

EDIT. Thanks for the Gold :)