5 ms·

> Flying is not a valid commute solution and never will be because of physics. All things equal, the energy requirements to change elevation will be too great t

> Flying is not a valid commute solution and never will be because of physics. All things equal, the energy requirements to change elevation will be too great to justify adoption. There are lots of technical roadblocks to feasible flying cars but the cost of the potential energy to change elevation is not one of them. The optimal altitude flown would be lower for shorter trips, and when normal cars must change elevation (i.e, drive over hills/mountains), they do not use so much fuel as to make the trips infeasible. In a flying car, much more energy is used fighting air drag and gravity drag.

iaw 10y ago
> The optimal altitude flown would be lower for shorter trips Where does the column of flying cars go? Do they expand vertically or horizontally as traffic increases? In the underpopulated area's of the US where 10% of the population lives this is a feasible mode of transit, what about the 90% that actually have traffic? If the cars broaden vertically it's a safety risk, if the cars broaden horizontally it's a violation of property rights (and a different safety risk), if the cars don't broaden it rapidly becomes inefficient and dangerous. Also, with the advent of KERS and other regenerative systems cars will be able to recapture the bulk of energy consumed for elevation changes. To my knowledge there's no such effective system for planes. So the efficiency on cars is still higher than air vehicles.
- jessriedel 10y ago
  > If the cars broaden vertically it's a safety risk, That's the evidence you're giving to dismiss the ability of flying cars to distribute over multiple altitude? 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. > Also, with the advent of KERS and other regenerative systems cars will be able to recapture the bulk of energy consumed for elevation changes. To my knowledge there's no such effective system for planes. So the efficiency on cars is still higher than air vehicles. No one is disputing that regular cars are more efficient than flying cars. But trucks are less efficient than container ships, and we still use the former when the latter is impossible or too slow. You said "Flying is not a valid commute solution and never will be because of physics", and this just isn't true.
  - inlineint 10y ago
    > 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.
    - jessriedel 10y ago
      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.
      - iaw 10y ago
        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?
        tomcam 10y ago
        Upvoted because you're right, but not sure why you felt it necessary to be so hostile
- mahyarm 10y ago
  Bridge chokepoints and other small hops over bodies of water / mountains are a great case for flying cars. It would be great for seattle, manhattan, SF, hawaii, islands, etc. You also don't need to build much infrastructure other than landing/takeoff sites. Large infrastructure alone, especially in a place like the USA is a big blocker.

iaw 10y ago

> The optimal altitude flown would be lower for shorter trips Where does the column of flying cars go? Do they expand vertically or horizontally as traffic increases? In the underpopulated area's of the US where 10% of the population lives this is a feasible mode of transit, what about the 90% that actually have traffic? If the cars broaden vertically it's a safety risk, if the cars broaden horizontally it's a violation of property rights (and a different safety risk), if the cars don't broaden it rapidly becomes inefficient and dangerous. Also, with the advent of KERS and other regenerative systems cars will be able to recapture the bulk of energy consumed for elevation changes. To my knowledge there's no such effective system for planes. So the efficiency on cars is still higher than air vehicles.

jessriedel 10y ago
> If the cars broaden vertically it's a safety risk, That's the evidence you're giving to dismiss the ability of flying cars to distribute over multiple altitude? 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. > Also, with the advent of KERS and other regenerative systems cars will be able to recapture the bulk of energy consumed for elevation changes. To my knowledge there's no such effective system for planes. So the efficiency on cars is still higher than air vehicles. No one is disputing that regular cars are more efficient than flying cars. But trucks are less efficient than container ships, and we still use the former when the latter is impossible or too slow. You said "Flying is not a valid commute solution and never will be because of physics", and this just isn't true.
- inlineint 10y ago
  > 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.
  - jessriedel 10y ago
    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.
    - iaw 10y ago
      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?
      - tomcam 10y ago
        Upvoted because you're right, but not sure why you felt it necessary to be so hostile
mahyarm 10y ago
Bridge chokepoints and other small hops over bodies of water / mountains are a great case for flying cars. It would be great for seattle, manhattan, SF, hawaii, islands, etc. You also don't need to build much infrastructure other than landing/takeoff sites. Large infrastructure alone, especially in a place like the USA is a big blocker.