Jammin, yes, like the others have said spacing out in a car in normal. I have recovered from anxiety and I know what you mean when you are in a conversation and you can't listen anymore. I always thought that I was just getting overwhelmed and just couldn't focus. I dissociated once in my life for just a few seconds before something in the environment snapped me out of it. Dissociation has a physical feeling to it. You know that you are doing it! Your urge is to panic and run. The not being able to focus on a conversation was different. There wasn't any physicalness to it (maybe anxiety only). Zoning out in the car is nothing like really dissociating either because this zoning out is pleasant. Dissociating is not pleasant!

This going away to avoid the present sounds like learned behavior from your past. I have no experience with this.