Some KTX passengers found high-speed travel in backwards facing seats dizzying. Along with dizziness, feelings of nausea, headache, and sleepiness could also be experienced. Motion sickness was also noted as having had a minimal affect on KTX passengers; however, it still made an impact on passenger ride comfort. When the original seats were selected for the KTX trains, the anthropometry of the main consumers, who were largely expected to be Korean, were not considered. The seat design was found to have a significant affect on how passengers on the KTX trains rated the experience of their trip. Among the various factors that were considered to be vectors of discomfort were the angle of joints and specific areas of pressure, which were discovered to be present after an analysis of questionnaires that were completed by recent passengers. The factors of the seats of concern to KTX passengers were the shape, pitch, width, and the amount of legroom between the rows of seats. Swivel seats, which can be turned into the direction of travel, installed only on First Class in KTX-I trains, were made standard on both classes on newer generations of trains.