Ideal in terms of travel time efficiency, not energy efficiency or space efficiency.

Travel time is the wrong property to optimize for when we're looking at transportation and urban design. It's the mistake we've made in America for the last century.

We should be optimizing for quality of life and health. Optimizing for those things yields design like Copenhagen -- bike paths, walking paths, trains and busses for longer trips. It's quiet. It's energy efficiency. It's much better for our health. It encourages healthy social interaction and the feel of community.

>Travel time is the wrong property to optimize for when we're looking at transportation and urban design.

You'll probably eat those words. Or maybe your grandchildren or great great grandchildren will.

The value of human time has been steadily going up for millennia. We used to have slaves build pyramids and pick cotton, now we use machines. We used to churn our own butter. Now there's enough wealth in the world that we can afford to have butter specialists make butter and logistics specialists get it to the store shelves. Tasks that we used to think it was reasonable to allocate human time and effort two we no wouldn't think about doing manually today.

I would be highly surprised if in the future we did not continue to optimize for smaller travel times. Of course there are energy and space trade-offs. I think it's highly likely that we will chose to solve the problems caused by those trade-offs rather than having people endure longer travel times when we have the power to shorten them (with tradeoffs).

Spending less and less human time on "overhead" tasks (like churning butter, washing clothes, traveling, etc.) has been a constant theme for millennia. I do not see any reason why that will change.

Flying autonomous vehicles can reasonably be energy efficient, and clearly are space efficient (due to the three dimensions that provide plenty of space).

Travel time is the correct property to optimize for my values. I don't want to spend unnecessary time in transit. That's a subjective value, of course.

You can optimize for quality of life, health and short travel times at the same time. Copenhagen might be a good target with current level of technology, not necessarily the technology of future.

I don't care for imposed social interaction due to public transportation. People don't really interact with strangers in public transportation anyway (in my culture that is).

> Ideal in terms of travel time efficiency, not energy efficiency or space efficiency.

Not even in terms of the first, because of the last; it's the optimal individual choice in terms of travel time, but making it the socially dominant option produces sprawl (because of space inefficiency); and flying doesn't actually change that (because any dense arrangement means high concentration near the endpoints, and because flight in built up areas is problematic.)

Ideally, I'd just walk and use no vehicles at all to be most effective.

This assumes lots of services, jobs, and housing all within decent walking distances which is quite common in older (European) cities.

Merely walking doesn't scale but the natural extension for longer distances is to walk to a suitable public transit stop, hop on the train/tram/subway, waiting for a while, and continue walking to your destination.

This will also effectively double the locations you might be interested in visiting: you can walk around near home and you can walk around near your workplace.

So, you can use the most effective mode of transport i.e. walking around hundreds of locations (shops, restaurants, services) but you can also switch the whole area by changing transit to another local centre.

It's like looking up stuff really fast in the whole cache line, and then making calculated jumps to read another location into your cache and continuing to traverse locally there.

Even more ideally you can fly anywhere quickly instead of settling for either long transportation times or walking to whatever is nearby.

This would be the case if businesses were scattered around like in the auto-centric USA.

There's no way any transport can be more efficient than me walking a couple of blocks and checking out maybe 100 doors to different businesses to be considered on my way.

The ideal "public transportation" being a private vehicle completely ignores climate change issues. Even an electric private vehicle needs to charge from the grid which so far isn't very sustainable, plus each private vehicle needs its own power. The fact of the matter is shared public transportation is the most sustainable option we have.

This is important - the idea that the future is a private flying vehicle is an artifact of 20th century science fiction. It does not fit into 21st century ecological and economic realities.

Agree with the current level of technology. That's why Boeing is developing new technology to solves these issues.

Due to noise and safety issues, none of these new VTOL aircraft are going to operate in residential neighborhoods. They certainly aren't going to land in your driveway. In some cases they might be a good option for short trips across congested urban areas, but they'll still have to operate from designated landing pads. So they won't do anything to solve the last mile transportation problem.

> In some cases they might be a good option for short trips across congested urban areas

Well, if you need to get from an uncongested area to an uncongested area with a congested urban areas in between and no bypass motorway, and no accessible public transit maybe.

If either origin or destination is congested adding take-off and landing traffic is just going to make things worse.

Private transports are efficient at delivering individuals to locations. Public transport has the advantage of delivering a lot of people to an approximation of their destination. The latter enables more urban density and more efficient cities overall.

There's nothing preventing "flying cars" of delivering a lot of people to various locations. 3D space is quite large.

"Private transports are efficient at delivering individuals to locations"

Not all locations though - I wouldn't dream of driving to work in central Edinburgh as the drive would be a pain, take longer and the parking would be more expensive than getting the train.

That’s not how “efficient” works. Not only do you look at each person individually instead of the whole system, in which everyone having their whole transport is ridiculously inefficient in required space, energy and coordination effort alone, it’s also likely to actually be so incredibly inefficient on the whole system that the value breaks down for each individual person, even if you completely overlook the drastic side effects on the whole system, by not actually getting anybody anywhere in a timely manner.

Thinking like this baffles me, I can only hope that you are very young.

If the vehicle is flying and autonomus (like what Boeing is developing), then there's plenty of space in three dimensions. Coordination should be solvable with software. Energy use is an interesting factor, of course. There are possibilities (like cheap nuclear power) to solve that.

Because those vehicles can move in the third dimension as easily as in the other two? Because this wouldn't require an intense amount of coordination between vehicles, and tons and tons of added security measures and protocols, given that cars can now literally fall from the sky and onto each other? Because the resources to build those magic cars are easily and sustainably acquirable? Because this does not need a much more involved inspection and maintenance infrastructure? Because energy considerations has been solved, and things "like cheap nuclear power" are safely and readily available? And the insane amounts of power required are so easy to distribute among those ubiquitous cars?

I just don't see how this is "efficient".

It's true that 2D is a lot easier than 3D. It would also require a lot of new technology. It is a solvable problem, though, and we need to solve it to some degree even today (due to airplanes). The need to solve coordination will only increase thanks to proliferation of drones, too.