Washington: Self-driving cars may make roads safer, save energy and improve mobility, but they could also cause motion sickness in some people, according to a new study conducted in six countries, including India.

Researchers asked more than 3,200 adults in the US and five other countries (India, China, Japan, Great Britain and Australia) what kinds of activities – many of which could cause motion sickness – they would do in a fully self-driving vehicle.

More than a third of Americans said they would do things that increase the likelihood and severity of motion sickness – reading, texting, watching movies or television, playing games or working.

More than half of Indians, 40 per cent of Chinese and 26-30 per cent of adults in Japan, Great Britain and Australia said they would engage in such activities. About 6-12 per cent of American adults riding in fully self-driving vehicles would be expected to experience moderate or severe motion sickness at some time, researchers said.

Similar percentages would also apply to residents in India, China, Japan, Great Britain and Australia, they said.

“Motion sickness is expected to be more of an issue in self-driving vehicles than in conventional vehicles,” Michael Sivak of the University of Michigan Transportation Research Institute said.

“The reason is that the three main factors contributing to motion sickness – conflict between vestibular (balance) and visual inputs, inability to anticipate the direction of motion and lack of control over the direction of motion – are elevated in self-driving vehicles,” said Sivak.

“However, the frequency and severity of motion sickness is influenced by the activity that one would be involved in instead of driving,” Sivak said.

Researchers found that more than 60 per cent of Americans would watch the road, talk on the phone or sleep while riding in a self-driving vehicle – activities that would not necessarily lead to motion sickness.

The percentage is roughly the same for China; higher in Japan, Great Britain and Australia; and lower in India. Sivak and researcher Brandon Schoettle suggest that manufacturers can design self-driving vehicles to lessen the likelihood of motion sickness: maximise the visual field with large, transparent windows; mount transparent video and work displays that require passengers to face forward; and eliminate swivel seats, restrict head motion and install fully reclining seats.

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