Engineering to curb motion sickness

Rear-seat video screens have to be located outside "the puke zone"

Published: April 24, 2014, 3:00 PM
Updated: November 22, 2021, 4:12 PM

Rear Seat Video Screen - Chrysler

I'll never forget my first ride in the back seat of Oldsmobile's now-forgotten 1998 Silhouette minivan. It's the first – and only – time in my life when I've come scarily close to being car-sick.

The reason for that anomalous occurrence wasn't the Silhouette's ocean-liner ride quality – although that may have been a contributing factor.

Primarily it was the result of watching a movie on the Silhouette's rear-seat video screen – an industry first in a volume-production model. The DVD system was standard equipment in the Silhouette's aptly named, top-of-the line Premiere model.

The guts of the system were encased in the back of the centre console but the screen flipped down from the roof, between the front-seat headrests.

In that position, the motion on the screen was framed by the contrasting movement of the landscape through the windshield, thoroughly confusing the synapses in my brain that govern spatial awareness – and motion sickness.

Given the millions of in-car video systems that have been produced and watched ad ifinitum since then – hundreds of hours by my own grand-kids – it's safe to say not everybody shared my initial experience.

But is that because they've evolved from a more visually-tolerant gene pool, or because the engineering of the systems has improved since then? Perhaps a bit of both.

For its part, General Motors says it has learned to place today's video screens outside what it calls "the puke zone."

In achieving that goal, the company's Human Factors engineering group enlisted the help of employees' children during past 'Take Your Child to Work Days'.

"We know through other scientific research that even if our eyes are focused on a fixed point – if we can see the outside passing by in the window – our brain is telling us that we are moving," said Don Shreves, the group's manager.

"But if our eyes are at a downward angle and do not see the view outside the vehicle, our bodies become sensitive to motion and increase the chance of sickness," he added.

It seems like a no-win situation.

To overcome the enigma, GM's engineers opted to keep the passenger’s eyes up and in a given spot. To determine the precise location required, they set up a DVD screen on a track that could slide fore and aft along the roof of a Buick Enclave.

Researchers recorded the responses of more than 75 kids who were asked when the screen distance was too close and too far away.

Then they graphed and compiled the data to determine the best location and turned the results over to the vehicle engineering team to integrate into the Enclave’s design.

Presumably, they and other manufacturers have found the sweet spot, for there doesn't seem to be an epidemic of car-sick kids.

I can't vouch for the fact myself, however, for I haven't watched a movie on a rear-seat video screen since my initial experience.