no not always. dissociation is a reaction to a trigger. A trigger can be good or bad. its anything that causes a person to feel emotions that they are not able to handle. I bet if you take time to check in with the alters that dont do the driving/shopping what ever activity that another alter takes over and does you will most likely find that there is some sort of emotion packed reason behind it. maybe that trigger is they dont like crowds, or that activity causes them to stress out because they dont know how to do it and cant figure it out ...theres all kinds of reasons that triggers a person/alter to dissociate (in other words switches into their various alters)

the result of dissociating due to a trigger revolving around driving is an alter takes control and does that for the host.

example when I got triggered at work in other words unable to do something at work the alter who's job purpose reason for being was to work would take over and do that for me.

when I was unable to do the shopping an alter would take over doing the shopping.

I know many people who's host (body person) is so far buried with in the system that they do not seem to exist and the internal system of alters are unable to drive/ no one takes control and does this for them because none of the alters contain that activity. they never had to form an alternate personality for that job, purpose, reason for being because driving was never an issue or traumatic event that caused the system to dissociate.

example here in the city we have a city transportation system of bus's and taxi's. a person can live their whole life without having to drive. therefore there for some people driving isnt something that triggers them into dissociating into an alter, nor is driving a trigger that causes their alters to dissociate from one to another.