How many decisions do you make with in one mile of driving?

Answer 1

It depends on conditions and additionally how you define "decision". If you're on a straight section of interstate with no other traffic, by whatever metric you use you will make fewer decisions... at least those involving driving... than you would on a busy street in town with lots of intersections.

For these reasons, any concrete number you may have seen associated with this type of question was effectively pulled out of someone's hind end and is essentially meaningless.