Around half of the population has had a personal experience of nausea when travelling by vehicle, even on straight roads. As any and every one of them will attest, it’s not a bit of fun.
In a self-driving car, the person in the driver’s seat becomes a passenger, able (and encouraged) to keep busy with activities other than steering and watching the road. That’s one of the advantages being promoted of the AV future, but this new freedom is likely to result in a big increase in the incidence of motion sickness (or formally, “kinetosis”). That’s because those who pass the journey time by reading, watching movies, playing video games or working on a tablet in the car have a relatively high chance of getting carsick.
Due to the increasing variety of mobility options and constant viewing of smartphone screens, the issue is rapidly growing more relevant. When autonomous vehicles become common, the percentage of passengers will increase because of drivers becoming passengers who no longer need to keep eyes on the road, and vehicle occupancy will likewise increase because of shared mobility.
Motion sickness is caused by repeated motion, as from a vehicle, that agitates the fluid in the inner ear. Then the symptoms of motion sickness appear when the central nervous system receives conflicting messages from the sensory systems, that is, the inner ear, eyes, skin pressure receptors, and the muscle and joint sensory receptors. For example: sitting in a car and paying prolonged attention to something inside—reading or using a smartphone, for example. The inner ears sense movement up and down, left and right, but the eyes see a static view, as if there’s no motion at all. The resulting sensory conflict is held responsible for the dizziness, lightheadedness, exhaustion, and nausea of motion sickness. Some people learn early in their lives that they’re prone to the condition. One reason for this is that the organ of equilibrium is still growing at that age, and the sensory system is particularly sensitive. With age, susceptibility decreases, but most people never lose it completely.
This summer will see the start of a new research project on motion sickness and autonomous cars at the Charité Hospital in Berlin. They will collaborate with automotive engineering experts from the Technical University Berlin to figure out how autonomous cars could be constructed to not make people sick, which situations are particularly problematic, and what the driving style should be.
UMTRI, The University of Michigan Transportation Research Institute, has flagged three main factors behind motion sickness: conflict between vestibular (inner ear) and visual inputs, inability to anticipate the direction of motion, and lack of control over the direction of motion.
Meanwhile, a variety of companies and groups are working on it. Here’s a look at some of them and their activities:
Daimler is among the companies working on improving the wellbeing of all passengers in vehicles, including reducing motion sickness (which they call by a more formal synonym, kinetosis). The vehicle concepts division of Mercedes-Benz is already taking the prevention of kinetosis into account in the early development phase of its products. As part of a study with 25 test subjects aged 21 to 56 years, they equipped a test vehicle with a special seating system in the back. It allowed participants to sit upright (23-degree incline) or reclined (38-degree incline) while performing certain secondary tasks with varying dynamics and required levels of attentiveness. The test subjects were asked to complete a quiz on a tablet, watch a movie, read, and play an action game while the test vehicle travelled along a defined test route.
After each round, there was a short break, during which subjects were asked about their personal wellbeing and given a performance test. As expected, the concentration-heavy game caused the highest levels of vertigo and motion sickness in most of the test subjects.
The reclining position resulted in a significant reduction in motion sickness, and was also considered particularly comfortable—and subjective performance was demonstrably increased in this relaxed position, as well. Stop-and-go traffic, on the other hand, was found to be particularly uncomfortable and an aggravating factor in kinetosis. The reclining positing is beneficial for preventing motion sickness, as the need for active, conscious, muscular stabilization of the head is reduced when the backrest is at a flat angle.
ZF, meanwhile, has developed a system that recreates a virtual movement for the brain: an ultrasound emitter panel placed behind the headrest generates vibrations of ambient air perceptible by the passenger. By generating these vibrations at different frequencies and amplitudes between each side, it is possible to rebalance the feeling of accelerations. This system can be completed by two other right/left rebalancing devices, such as LEDs with several vertical LEDs and a frequency difference of the loudspeakers of the audio system.
These solutions are the results of the joint study of ZF and the SNNU (Systems Neuroscience & Neurotechnology Unit) at the University of Saarland in Germany over 10,000 km and bringing together more than 50,000 GB of physiological markers in the central and autonomous nervous system, in the form of thermographic data, imagery, and data on driving dynamics. A set of sensors is also developed so that the driver of the autonomous vehicle can know in advance if a rear passenger begins to feel ill—then the car can be programmed to adapt the driving style accordingly.
At Faurecia, a leading idea on the subject is a combination of seated posture to reduce the feeling of motion and allowing the occupant to see more of what is happening outside the vehicle, with a view on many promising concepts from active seat-based systems, to responsive systems that sense symptoms of motion sickness via passengers’ vital signs (in partnership with ESP, a French lab that uses cognitive science to optimize human wellbeing and performance in different situations).
A Visteon representative hints at that company’s work, saying “In an autonomous car, you don’t know when it will decide to exit the road or change lanes. The technology we are building in the cockpit, like augmented reality, can prepare the occupants”.
Yanfeng Automotive Interiors says the key is in “the behavior of the envelope”—that is, the box in which you will be sitting. They see their target as making movement as smooth, predictable, and linear as possible.
Among other ideas being developed and trialled: “Boarding Glasses” from French startup Boarding Ring, which partnered with car-maker Citroën, as previously reported in DVN-I.
The mobility of the future is changing, and so are the needs of passengers. This is why already today new interior concepts are needed to mitigate problems amplified by new mobility scenarios. The prevention of kinetosis is a centrally important part of this future.