I have a problem of car sickness(vomiting) in traveling in bus. But not on other vehicles such as car, taxi, ship, train( I feel comfortable there). I even feel it when bus isn't start moving. I dont like the smell of bus(even the clean one)..due to this i can not travel in bus.. I can not stay even 15 minute without vomiting(in bus) ... I always take other transportation option... I think the problem is probably psychological.