Studies have shown that, when driving on familiar routes in this state of subconscious awareness, we pay more attention to relevant stimuli that will demand action, (like road signs and behavior of other road users) than to billboards and ads. This is referred to as 'cognitive resources saving.' This means that, although you pay attention at the time, you do not allocate resources to store this information for later recall because it is not necessary.
Research has shown that subconscious driving reduces attention to the act of driving, but not necessarily general security and road safety. Should something happen that is perceived as dangerous, subconscious driving 'switches off' and most drivers can then perform normally in most cases.
In cases of subconscious driving, the basal ganglia (a very primal part of the brain that controls voluntary but barely conscious actions) has taken control. The basal ganglia is associated with a variety of functions such as the control of voluntary motor movements, procedural learning, routine behaviors or "habits," eye movements, cognition and emotion.
