Last year, 13 million new electric vehicles rolled out onto China’s roads as the country continued a rapid transition to new energy. But as eco-friendly rides begin to dominate transport, the new technology appears to be hauling old baggage – motion sickness.
After investigating growing numbers of reports of EV passengers feeling dizzy, nauseated or breaking into cold sweats, researchers in Japan may have come up with a low-tech solution for the hi-tech problem: a simple sound that can be downloaded and played before a passenger’s next journey.
Studies have revealed that EVs are more likely than conventional combustion engine vehicles to induce queasiness because of their unique acceleration and deceleration characteristics.
According to researchers at Chongqing University and China Automotive Engineering Research Institute, motion sickness can affect the health as well as the comfort of vehicle passengers, who may often feel fidgety and tense while riding in the vehicles.
For instance, regenerative braking systems can induce motion sickness, according to findings published last month by a team led by the Hong Kong University of Science and Technology (Guangzhou).
The system is a unique function in EVs that converts kinetic energy into electrical energy when the vehicle is slowing down to charge the vehicle’s battery, resulting in low-frequency deceleration, which can provoke symptoms of motion sickness.
Researchers from Shanghai University and Chinese carmaker SAIC Motor found that for electric vehicle passengers, “the brain’s functional connectivity undergoes reorganisation to cope with the physiological and psychological stress induced by motion sickness”, according to their study published in October.
To relieve motion sickness, scientists at Japan’s Nagoya University have found that listening to a 100Hz tone for one minute before riding in an EV could help alleviate the problem.
The findings, which they said were a safe and effective method to ease symptoms such as lightheadedness and nausea, were published in the peer-reviewed journal Environmental Health and Preventive Medicine in March.
“Vibrations at the unique sound stimulate the otolithic organs in the inner ear, which detect linear acceleration and gravity,” lead author Masashi Kato said in a university statement.
“This suggests that a unique sound stimulation can broadly activate the vestibular system, which is responsible for maintaining balance and spatial orientation.”
Study participants listened to the audio clip for a minute and then went on a swing, a driving simulator or a vehicle where motion sickness was induced.
Their symptoms, such as lightheadedness and nausea, were alleviated, the researchers found.
“These results suggest that activation of sympathetic nerves, which are often dysregulated in motion sickness, was objectively improved by the unique sound exposure,” Kato said, referring to the part of the nervous system that promotes the fight-or-flight response.