Makes me wonder: I have two driving modes, not autopilot, but not as aware as I could be, and then tracking everything I can because something odd is going on

Makes me wonder: I have two driving modes, not autopilot, but not as aware as I could be, and then tracking everything I can because something odd is going on and I'm trying to avoid a bad scenario. Perhaps I'm a bad driver, but I suspect this is normal, kind of in a low-attention mode most of the time, but if the car a lane over starts to change lanes too close, you go into high-alert mode. I wonder if there are studies on how often humans need to do this sort of "disengagement" for lack of a better term? Not sure how you'd measure it, perhaps with more eye movement than normal? Dunno.