Korea and foreigners with motion sickness?

So something of interest.  The few foreigners I have talked to have found that things that used to not bother them do here.  Buses cause one friend not to feel so good while traveling now.  Another can't ride in the back seat or read a book in a car anymore.  Me, I've not been able to read a book or be super crowded with packed stuff around me... but here takes it to a new level.  I have to use all my focusing techniques I learned from past experiences to avoid getting sick, and even then I don't feel so good afterwards.  It is another phenomena of Korea I suppose.  Only trains seem to not have that affect that I can tell.