Motion sickness in public road transport: the relative importance of motion, vision and individual differences.

The relative importance of vehicle motion, a view of the road ahead and passenger characteristics in the causation of motion sickness in road transport has been investigated using survey data from 3256 coach passengers and measurements of coach motion. Overall, 28% of passengers said they felt unwell during coach travel. Prior experience of sickness, travel regularity and age were the factors most highly correlated with illness. Increased vehicle motion and poorer forward vision also correlated with illness. Little difference in illness was apparent with a good view of the road ahead, regardless of motion exposure, although vision alone was not sufficient to eliminate passenger sickness entirely. The results suggest that travel sickness could be significantly reduced by improved forward external vision and that improved forward vision may be particularly beneficial for individuals new to coach travel and for those who travel less often.