BBC News

Why electric cars might be making some passengers feel sick

Research shows there are several reasons people might experience motion sickness in electric vehicles.

The article is based on anecdotal evidence, which it points out, but even then it doesn’t ask the right questions of the people interviewed to try and tease out some rigor.

Yep. Might help to look at driving styles - EV drivers may occupy a demographic that tend to accelerate and decelerate more rapidly, and take advantage of EVs higher low-end torque. Based on my own experience (and spouse's) as passenger in an EV, I would also suspect the way some regenerative braking is calibrated, which means that actual data should be gathered to see if the effect is also appearing in hybrids.

I suspect the sound thing is a red herring. If that were a necessary cue for the brain/vestibular system, more people would be ralphing their lunch from golf carts or electric light rail. And EVs aren't completely quiet - there's motion-indicating noise from wheels and air resistance and a motor whine.

Edited Saturday at 05:45 PM2 days by TheVat

What bothers me about electric ( and hybrid ) vehicles, is the fact, that due to regenerative braking, the vehicle can slow down without the brake lights going on.
Other than that, I have no issues.

I know ... anecdotal.

2 hours ago, TheVat said:

Yep. Might help to look at driving styles - EV drivers may occupy a demographic that tend to accelerate and decelerate more rapidly, and take advantage of EVs higher low-end torque. Based on my own experience (and spouse's) as passenger in an EV, I would also suspect the way some regenerative braking is calibrated, which means that actual data should be gathered to see if the effect is also appearing in hybrids.

I suspect the sound thing is a red herring. If that were a necessary cue for the brain/vestibular system, more people would be ralphing their lunch from golf carts or electric light rail. And EVs aren't completely quiet - there's motion-indicating noise from wheels and air resistance and a motor whine.

Yes, I have read about something to do with regen braking, but it seems very unclear what feature of this is responsible. I can't immediately see why regen braking would feel any different from traditional disc brakes. Is it really to do with the braking system or just inexperienced EV drivers driving jerkily or something? I can imagine if it is not easy to "feather" the braking when coming to a stop that might induce nausea. But I can hardly believe the manufacturers would be so inept as to offer a vehicle in which one cannot stop smoothly.

Have braking systems gotten worse? I had one of the first Prius hybrids made and I couldn't distinguish any difference between that car and any of the other cars I ever drove so far as brakes went. IMO it probably has to do with cues, especially audible ones, when changing speeds. I wonder if they looked at highway vs city driving?

3 hours ago, TheVat said:

Yep. Might help to look at driving styles - EV drivers may occupy a demographic that tend to accelerate and decelerate more rapidly, and take advantage of EVs higher low-end torque. Based on my own experience (and spouse's) as passenger in an EV, I would also suspect the way some regenerative braking is calibrated, which means that actual data should be gathered to see if the effect is also appearing in hybrids.

In addirion EVs are typically ~25% heavier and have a much lower CoG located centrally between the wheels rather than being dominated by the CoG of a combustion engine. In many respects, this is a chassis designer's dream as the vehicle suffers much less body roll during cornering, acceleration and braking, providing improved road-holding and increasing driver confidence when manoeuvring at speed. Everything one might want if you're a racing driver (except for the increased weight)

Chief impact on the suspension is a requirement for relatively stiffer spring rates and firmer rebound damping, which is going to transfer more higher frequency vibrations (road surface imperfections etc) into the cabin.

From a passenger point of view, the higher sprung weight can offset some of the harshness of the firm suspension particularly on low frequency road undulations. However, the inherent reduced body roll of the cabin does not apply to the passenger, since they are held in place only by a sealt belt (if that). Any change in velocity is likely to result in a greater shift of body position relative to the cabin, and impact their sense of balance. I understand that the link between impaired balance and feelings of nausea is fairly well established. This is where I would look. Not that I'm an expert, but I've dabbled in chassis design a bit at times.

Brings to mind those anti-static dog tail things cars used to have dangling at their rears. My age is showing.

15 hours ago, sethoflagos said:

However, the inherent reduced body roll of the cabin does not apply to the passenger, since they are held in place only by a sealt belt (if that). Any change in velocity is likely to result in a greater shift of body position relative to the cabin, and impact their sense of balance.

Seems like a reach. There must be a range of car body types and suspensions and overall weights, which would mean variation in such effects in both ICE and EVs. But who knows, maybe worth testing. Researchers will have to pay well, to get volunteers with motion sickness tendencies. I can see the ads now: "Earn money with your vomit!"

From what I've read about it, it might have something to with certain physically-sensed environmental cues being missing or diminished in EVs. Generative braking appears to add to the negative comments about EVs

Edited Sunday at 03:30 PM2 days by StringJunky

1 hour ago, StringJunky said:

From what I've read about it, it might have something to with certain physically-sensed environmental cues being missing or diminished in EVs. Generative braking appears to add to the negative comments about EVs

The only things that would make sense to me would be more brutal acceleration from overenthusiastic drivers, or the absence of traditional sounds from engine and transmission. I cannot see why regenerative braking would have any effect different from disc brakes, unless badly driven for some reason (why?).

I can understand why absence of sound during acceleration might make it a bit harder to rationalise the sensation of being pressed back in your seat, and possibly harder to anticipate it and (subconsciously) brace accordingly.

Edited Sunday at 04:47 PM1 day by exchemist

1 hour ago, TheVat said:

Seems like a reach.

Just throwing up some ideas to consider. Here's another.

Generations of drivers have grown up with learning how to drive cars with inherent understeer due, at least in part, for front-engined ICs to have more weight acting on the front wheels than the back, particularly as they decelerate into a turn. Now they have to learn how to handle a vehicle with more neutral steering characteristics and a 'twitchy back end'

Google 'motion sickness in rear-engined vehicles' and you'll find a lot of references going back many decades. Again, passenges in the rear seats especially are subject to mismatches between physical motion and visual cues leading to dizziness and nausea. Counter-steering in an oversteering condition is a learnt, somewhat counterintuitive response, so why should we not expect some passengers to have a rough time while inexperienced drivers get the hang of it?

Some idea of the driving skills involved (at least in a racing scenario) can be seen on https://www.youtube.com/watch?v=kQ5leWLp65I

Edited Sunday at 05:05 PM1 day by sethoflagos

One point I noticed in the article is that it is passengers that get to feel sick (or not) not the drivers.

The only electric car I have driven is a Kia Niro; I have also been a passenger in it and several others, including hybrids.

I did not experience any difference in any of them, apart form the obvious different handling characteristics.

The only annoying factor for me was finding how to turn off the annoying lane following feature, which I consider dangerous.

1 hour ago, exchemist said:

The only things that would make sense to me would be more brutal acceleration from overenthusiastic drivers, or the absence of traditional sounds from engine and transmission. I cannot see why regenerative braking would have any effect different from disc brakes, unless badly driven for some reason (why?).

I can understand why absence of sound during acceleration might make it a bit harder to rationalise the sensation of being pressed back in your seat, and possibly harder to anticipate it and (subconsciously) brace accordingly.

Apparently, pulling your foot away from the accelerator too quickly makes the deceleration more annoying. Used incorrectly, it can feel like you are slowing down all the time. This is about the passenger's experience.

1 hour ago, sethoflagos said:

Generations of drivers have grown up with learning how to drive cars with inherent understeer due, at least in part, for front-engined ICs to have more weight acting on the front wheels than the back, particularly as they decelerate into a turn. Now they have to learn how to handle a vehicle with more neutral steering characteristics and a 'twitchy back end'
...
Counter-steering in an oversteering condition is a learnt, somewhat counterintuitive response, so why should we not expect some passengers to have a rough time while inexperienced drivers get the hang of it?

I drove a mid-engined two seater for quite a few years. When the back end started coming around on you, it required all your concentration to fight it back on course.
Drove a Porsche 911, rear engine car, ONCE, and I spun it twice on the first aggressive corner I took.
Not pleasant, and I imagine it would take getting used to.

39 minutes ago, studiot said:

The only annoying factor for me was finding how to turn off the annoying lane following feature, which I consider dangerous.

Lane departure warning, though annoying, I can live with; lane following, where the steering wheel fights your lane changes, is quite unnerving.

I suppose, since passengers don't see the visual cues of upcoming 'departures' from smooth driving, the unexpected 'departures' could lead to disorientation/queasiness, especially in when the driver is unaccustomed to differences in EV driving/reacting.

13 minutes ago, StringJunky said:

Apparently, pulling your foot away from the accelerator too quickly makes the deceleration more annoying. Used incorrectly, it can feel like you are slowing down all the time. This is about the passenger's experience.

I talked to a sufferer today, and she told me it seemed likely to be the regen braking. She said that if one has motion sickness, the braking has a weird pulsation to it and, as you said, can feel like deceleration is happening for too long or where you don't expect it. (And she confirmed most MS happens to passengers, because drivers get more feedback and are controlling changes in motion so likely expecting them. I asked a family member who used to get MS and they also agreed that being the driver alleviates most of the symptoms.)

48 minutes ago, TheVat said:

I talked to a sufferer today, and she told me it seemed likely to be the regen braking. She said that if one has motion sickness, the braking has a weird pulsation to it and, as you said, can feel like deceleration is happening for too long or where you don't expect it. (And she confirmed most MS happens to passengers, because drivers get more feedback and are controlling changes in motion so likely expecting them. I asked a family member who used to get MS and they also agreed that being the driver alleviates most of the symptoms.)

This reminds me of something my grandad told me about when the aeroplanes flight controls were connected by tension wires and later changed to actuated. The engineers had to put some 'feel' or resistance back into the controls. Same thing will likely evolve with EV's, I guess. He apprenticed in 1936, so he worked with wood and canvas prop planes, through Lancaster and Vulcan.

12 minutes ago, StringJunky said:

This reminds me of something my grandad told me about when the aeroplanes flight controls were connected by tension wires and later changed to actuated. The engineers had to put some 'feel' or resistance back into the controls. Same thing will likely evolve with EV's, I guess. He apprenticed in 1936, so he worked with wood and canvas prop planes, through Lancaster and Vulcan.

Most actuated controls, such as the HOTAS pitch/roll control stick in fighter planes, now rely on 'force sensing', and don't actually move.

1 minute ago, MigL said:

Most actuated controls, such as the HOTAS pitch/roll control stick in fighter planes, now rely on 'force sensing', and don't actually move.

Interesting. So, over the ensuing decades, pilots never actually migrated to force-free controls.

Edited Sunday at 08:15 PM1 day by StringJunky

1 hour ago, TheVat said:

I talked to a sufferer today, and she told me it seemed likely to be the regen braking. She said that if one has motion sickness, the braking has a weird pulsation to it and, as you said, can feel like deceleration is happening for too long or where you don't expect it. (And she confirmed most MS happens to passengers, because drivers get more feedback and are controlling changes in motion so likely expecting them. I asked a family member who used to get MS and they also agreed that being the driver alleviates most of the symptoms.)

Pulsation? What would cause that?

1 hour ago, exchemist said:

Pulsation? What would cause that?

Integration of regenerative braking with anti-lock cadence braking?

Especially with one pedal EVs in urban driving where the vehicle is continually switching between ecceleration and deceleration.

3 hours ago, exchemist said:

Pulsation? What would cause that?

Damdifino. Seth might have a plausible reason. I will spare y'all my rant on one pedal EVs, but...not my cuppa.

What makes me wistful sometimes is the way the whole conversation in the US about EVs changed since the first Earth Day. I can remember from then how the future for a clean environment was seen as more in mass transit systems and less in personal vehicles. Then a lot of the movement gave up on that and tacked more to the center. The suburbs kept growing and that culture was welded to the private vehicle concept that went with that, "soccer moms" and all. (Now that all vehicles are so expensive, I'm starting to notice Zoomers and Millennials headed back to the older paradigm.

13 hours ago, TheVat said:

I talked to a sufferer today, and she told me it seemed likely to be the regen braking. She said that if one has motion sickness, the braking has a weird pulsation to it and, as you said, can feel like deceleration is happening for too long or where you don't expect it. (And she confirmed most MS happens to passengers, because drivers get more feedback and are controlling changes in motion so likely expecting them. I asked a family member who used to get MS and they also agreed that being the driver alleviates most of the symptoms.)

Yes, but it has been known for decades that drivers don't generally get car sick, so this can't be the explanation for why it is worse in EVs.

I looked up the one pedal issue and found an explanation of how it works in What Car: https://www.whatcar.com/advice/owning/what-is-one-pedal-driving-and-how-does-it-work/n27129

Evidently (and to my surprise) regen braking is only activated by releasing the accelerator, not by applying the brake pedal, and the degree to which it cuts in as you start to lift off the accelerator is typically a setting you can adjust. If you have it set to maximise regen, it can be a bit sensitive and can lead to over-deceleration unless you use it with a very light touch. So I can imagine some drivers being a bit clunky, over-decelerating and then re-accelerating to correct for that, repeatedly, which could easily lead to motion sickness. I didn't see anything in the way regen braking intrinsically works that would lead to pulsation, but I suppose if it is too sensitive the driver may be constantly adjusting the degree of braking, which would produce a nasty effect.

From the article, the moral of the story is to have regen braking set to be mild only, similar to the engine braking on the overrun in an IC vehicle, and to use the brake pedal to supplement it. But clearly, one needs a bit of practice to drive an EV smoothly. (This is useful for me actually, as I need to replace my ~20 yr old VW soon and was intending to buy an EV.)

8 hours ago, exchemist said:

Evidently (and to my surprise) regen braking is only activated by releasing the accelerator, not by applying the brake pedal, and the degree to which it cuts in as you start to lift off the accelerator is typically a setting you can adjust. If you have it set to maximise regen, it can be a bit sensitive and can lead to over-deceleration unless you use it with a very light touch.

Exactly.
And that leads to the EV in front of you slowing down, without brake lights going on.
Just annoying if you're paying attention; disastrous if you're distracted.

18 hours ago, TheVat said:

I can remember from then how the future for a clean environment was seen as more in mass transit systems and less in personal vehicles.

Used to be expected that EVs were supposed to replace ICVs.
What actually happened is that every EV owner who uses his EV for 'urban' errands, also has a IC truck, for heavy hauling and long trips.

16 minutes ago, MigL said:

Exactly.
And that leads to the EV in front of you slowing down, without brake lights going on.
Just annoying if you're paying attention; disastrous if you're distracted.

That’s not what I read in the What Car piece. According to that, regen braking does illuminate the brake lights.