A study released this week says 6-10 percent of American adults in fully autonomous self-driving vehicles “would be expected to often, usually, or always experience some level of motion sickness.”

This is one finding in the survey, research and analysis conducted by Michael Sivak Brandon Schoettle or the University of Michigan Transportation Research Institute Ann Arbor, Mich.

The mention of “Americans” is relevant as the researchers found slightly varying responses to a survey leading to their conclusions depending on whether the respondents were from the U.S., China, India, Japan, the U.K., and Australia.

Speaking further of Americans, “6-12 percent of American adults riding in fully self-driving vehicles would be expected to experience moderate or severe motion sickness at some time,” says an abstract for the research.

“Again, the highest expected percentage range is for Indians (8-17 percent),” says the abstract. “(The differences between the nationalities are due to the differences in the expected involvement in activities that individuals would be doing while riding in fully self-driving vehicles.”

In all cases a varying degree of motion sickness led the researchers to posit that “motion sickness is expected to be more of an issue in self-driving vehicles than in conventional vehicles.

Why? Three reasons that add up to having no control, losing sense of direction while in the car and sickness that results which the researchers say is akin to seasickness.

“The reason is that the three main factors contributing to motion sickness (conflict between vestibular 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.

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

Motion sickness is a physical condition, a response to the disorienting and upsetting circumstances that at its more extreme can include vertigo and vomiting said the researchers citing comprehensive research from 1975 on motion sickness.

How that is relevant today and into the future is the study examines how people will respond to cars in which they may one day be passive occupants.

What the occupants are doing appears to make a difference in how sick they will get, suggests the research abstract.

Details such as what direction one is looking at while talking on a phone while riding in an autonomous vehicle, or the same for other activities like watching TV, working, playing games also makes a differnce. In general a “downward gaze” can bring on symptoms of motion sickness, says the paper.

Whether humans will adapt and essentially be able to get over the tendency to get motion sickness appears to be an open question as some results are extrapolated and not the result of long-term mass exposure to actual autonomous vehicles.

Also whether future autonomous passengers may resort to antiemetic medications appears a possibility.

The researchers concede more study will be needed but their results are published after extensive analysis of the data at hand.