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Comment by blunte | Hacker News Reader

Watching videos of "normal" people riding as passengers in fighter jets, you often see them pass out briefly. The pilots are have the training and strategies to push their G limits much much higher, but even so it's still a risk.

I wonder how long until we see a G-LOC accident in a modern fast accelerating electric car... I'm sure today's fastest accelerating street legal cars can do things to a body/brain that some people wouldn't be able to tolerate. (And also, if you consider how much ground you cover in the very brief 0-60 of a modern Tesla, it suggests that a poor choice with the right foot could lead to a very quick bad situation!)

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Two things make that unlikely; cars have to grip the road and by the time you're getting close to G limits tires will start to skid and second the forces aren't in the right directions. For the former the closest a car gets to the levels that induce G-LOG are Formula 1 cars during braking (~5G) and during cornering (4-6G) [0] so even the highest performing cars out there you're just barely approaching where you might threaten G-LOC. The latter is why I think it won't really happen though because the acceleration is (basically [1]) never vertical like in fighter jets during climbs and turns. The forces in a car are, w.r.t. the human riding, forwards, backwards, and side to side and those directions don't force blood out of the head. Braking gets closest because the feet are furthest forwards but it's not quite the same.

[0] Acceleration is a measly ~2G at peak

[1] To avoid pedantry there is a case but that's on extremely high bank turns that only exist on test tracks really, NASCAR track banks might get close but I don't think get Gs there get high enough before cars break free up into the wall to threaten G-LOC.

Indy cars IIRC have run into the problem on banked tracks.

They did something to slow the cars down and remove the need for G-suits.

Indy cars got to around 5G, which is pretty hard to sustain without a G-suit.

The 9G stuff in the F-16/F-22 absolutely requires the G-suit and the reclined seat which changes the force vector.

I've motorcycled on a NASCAR track, but not a very steeply banked one relative to the superspeedways. Even the lower banking changes the way turns feel in a very dramatic way though.

The Firestone Firehawk 600 got cancelled over concerns of g-loc. It had sustained g-loads of around 5.

https://en.m.wikipedia.org/wiki/Firestone_Firehawk_600

So yeah only really an issue in open wheel cars on the highest banked turns in racing like I was talking about in [1].

Even the latest Tesla only reaches ~1.5G - not even that. G-LOC won't happen until 5 or 6, so I think we're a way off yet!

Considering how faint some passengers have looked with my boy-racing in the past, I suspect the G limit for some people is much much lower :).

It wouldn't necessarily need to be g-forces, given how many Americans have severe underlying health issues, you might just go over a rough bump and have a stroke or something.

Roller coasters tend to hit a good amount of gs, but if you pass out you'll be fine since you're not driving. One wonders if a Tesla detects its pilot unconscious can it bring itself to a full emergency stop. Automatically contact emts and then automatically distribute snacks to the arriving EMTs

That's for young, fit, etc people. Some quick googling says a particularly susceptible person might very well pass out at as low as 3 Gs. Still way below what a Tesla can pull, though.

Cars generate horizontal forces, and won't drive the blood out of your head into your legs.

Unless the road is banked: https://en.wikipedia.org/wiki/Firestone_Firehawk_600

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