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Comment by inlineint | Hacker News Reader

> Once we've accepted the hypothetical that technology allows for a single car to fly from A to B safely (which is almost certainly automated), it seems clear that having cars move at different altitude will be trivially possible.

In real world we can't accept this because there are always unpredictable factors, we can only say that probability of a safe flight in a single car is say 99.999%. Then if there are 20 cars one right above another, then probability that none of them crash is only 99.98%, and it could damage all cars below it, so the resulting probability of safe flight in a car reduces to something of order 99.99% instead of 99.999% for a single car. And 99.99% is really not safe enough for everyday flying during many years.

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Avoiding a car that crashes in the lane next to you is a lot harder than avoiding a car that falls 100 feet from above. Yet we have multi-lane highways.

That's an asinine statement if I've ever read one.

I've been present for 2 highways collisions, avoiding them is super easy. Which is why full lane closures and multi-car pile-ups are as infrequent as they are relative to the frequency of two car accidents.

A vehicle that falls from 100 feet above will be accelerating unlike vehicles in an accident on a highway which will rapidly decelerate.

Furthermore, you now have multiple vehicles taking evasive action based on dynamic predictions that cannot incorporate a collision. The second that one car hits another you're going to lose a chunk of your column from pachinko like bouncing.

Now, instead of a small mechanical failure you can have drastic loss of life because all of the occupants plummeted to their death.

Do you work for Uber?

Upvoted because you're right, but not sure why you felt it necessary to be so hostile

I'm trying to reduce the hostility of my posts. What parts of this do you feel was hostile?

Edit: We've hit the end of the reply chain. I see your point about both the opening and closing sentences. Is there any way to say the first one without coming off as hostile? My goal/point was trying to demonstrate how patently wrong the earlier statements were.

I commend your desire to improve your posts. That's something that's always on my mind as well.

From my unsolicited, third-party perspective, two things jump out at me.

- You could do without the first sentence entirely.

- The insinuation that the parent is possibly a shill (an Uber employee)

The rest of it is fairly neutral.

Most cool. Proud of you. grzm said it exactly.

My goal/point was trying to demonstrate how patently wrong the earlier statements were.

The evidence or examples you provide should make that clear. Unless you have very strong irrefutable evidence, I would hesitate making any absolute statement declaring someone wrong. What does it gain you? No one likes to be told outright they're wrong. The goal shouldn't be to score points: it should be to reach common understanding.

If this is something you'd like to cultivate further, you might find the references in my profile useful. I refer to them myself regularly.

I'll assume based on your comments below that you retract the hostile language, so I'll now reply.

As I mentioned earlier, the future we are talking about is one with self-driving cars. The fact that the vehicles are accelerating is much less of a concern than sheer number of seconds allowed for an automated system to take evasive maneuvers. (Coordinating evasion is also much easier for automated systems, and traffic collision avoidance systems are widely used in planes, but this is a secondary point https://en.wikipedia.org/wiki/Traffic_collision_avoidance_sy... )

Your anecdotal experience is not really informative. But what is informative are car and plane accident rates, and the fact that altitude separation for planes is already a standard practice for avoiding collisions.

https://en.wikipedia.org/wiki/Separation_(aeronautics)#Verti...

It is a strong contributor to the fact that mid-air collisions are much more rare than the multi-car pile-ups from having cars in adjacent lanes. As I read your logic, you would assert that planes would be better off flying parallel, all at the same altitude, so as to avoid the need for grade separation. But this is not how air traffic is managed. Yes of course planes are able to separate out further horizontally than cars can (and just as a flying car would be able to), and this reduces the risk of collision debris dropping down on top of any other random plane. But this clearly does not mean that if, for whatever reason, planes became more horizontally restricted, they would make less use of vertical space.

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