We have these things called "inner ears." I'm pretty sure deaf people have them, too.

Nature's accelerometers.

I've had mine go bad, and it wasn't fun.

Just sayin'...

Were you unable to drive when your inner ears weren't functioning?

I guess so.

I was unable to stand up.

Sounds horrible. I can understand that stopping you from cycling, but if you could have managed to sit in a car, would you have been able to drive it? I can imagine that inner ear issues can sometimes affect vision too as my wife suffered from positional vertigo for a while and I could see her eyes flicking rapidly when she was getting dizzy. (I did find a helpful YouTube video about a sequence of positions to put the sufferer through which basically helps to remove the otoliths from the ear canal).

In my case, it was a brain tumor. Took a bit more than Lotus Position.

It all came out OK, in the end, but it was touch-and-go for a while.

Ouch!

Not quite a Lotus Position, but I used the Epley Maneuver on her which immediately lessened her symptoms: https://en.wikipedia.org/wiki/Epley_maneuver

When the vertigo is bad, you can't even go as a passenger in the car because the movement is literally sickening.

Even driving with mild vertigo could be difficult because you want to restrict your head movement.

Source: my dad gets Benign paroxysmal positional vertigo (BPPV)

I'd recommend him trying the Epley Maneouvre as it's quick and easy to do (needs someone to help though) and is unlikely to make anything worse.

Thanks. I've tried to encourage him to learn it. He's stubborn and isn't interested. He's had physio do it when he was hospitalized...

He's mentally sharp, and has a science background, but nope!

vestibular system

There are more than three senses.

Yes and they're not really of much use in driving safely unless you're referring to some spidey-sense of danger.

I am not 100% sure which “sense” this would be, but when I drive I can “feel” the texture of the road and intuit roughly how much traction I have. I’m not special, every driver does this, consciously or not.

I am not saying that you couldn’t do this with hardware, I am quite confident you could actually, but I am just saying that there are senses other than sight and sound at play here.

Whilst that might feel re-assuring that you're getting tactile feedback, I doubt that there's many situations apart from driving on snow and ice that it's of much use. Fair enough if you're aiming for a lap record round a track, but otherwise you shouldn't be anywhere near the limit of traction of your tyres.

Snow, ice, and rain are cases that still need to be accounted for so that really doesn’t dispel anything I said.

I'm using inertial senses from my inner ear. I feel the suspension through the seat. I feel feedback through the steering wheel. I can feel the g forces pulling on my body.

Yes, but in what specific circumstances do they change your driving behaviour? If you weren't able to feel the suspension through your seat, how would your driving become less safe?

Pretty much all of them. The difference between driving a car and playing a video game is remarkable.

But that's sort of besides the point: why would you not use additional data when the price of the sensors are baked into the feature that you're selling?

One quick obvious example, they put tactile features on the road specifically so you can feel them. Little bumps on lane markers. Rumble strips on the boundaries. Obvious features like that.

While it doesn't often snow or ice up here (it does sometimes), it does rain a good bit from time to time. You can usually feel your car start to hydroplane and lose traction well before anything else goes wrong. It's an important thing to feel but you wouldn't know it's happening if you're going purely on vision.

You can often feel when there's something wrong with your car. Vibrations due to alignment or balance issues. Things like that.

Those are quick examples off the top of my head. I'm sure there are more.

Of course, all these things can be tracked with extra sensors, I'm not arguing humans are entirely unique in being able to sense these things. But they are important bits of feedback to operate your car safely in a wide range of conditions that you probably will encounter, and should be accounted for in the model.

As for auditory feedback, while some drivers don't have sound input available to them (whether they're deaf or their music is too loud or whatever) sound is absolutely a useful input to have. You may hear emergency vehicles you cannot see. You may hear honking alerting you to something weird going on in a particular direction. You may hear issues with your car. Those rumble strips are also tuned to be loud when cars run over them as well. You can hear the big wind gusts and understand those are the source of weird forces pushing the car around as opposed to other things making your car behave strangely. So sure, one can drive a car without sound, but its not better without it.