# Urban Planning in 3-Dimensions

So we have both flying cars and jetpacks. Presuming they each act like their counterparts (cars go as fast as cars, but in three dimensions; jetpacks are like cyclists), and that they are becoming just as ubiquitous as their counterparts: what should an Urban Planner consider in city-design?

This is near-future on Earth, with new opportunities for access, but nothing like the jetsons, floating cities, or any of that "nonsense" ;).

To narrow it, this is in Western cities, and, as a metropolis, fairly progressive.

• Sounds a lot like Coruscant from star wars, definitely some inspiration there. – newton1212 Jun 6 '15 at 1:05
• The number one inclusion should be a ban on flying cars and jetpacks. With the number of bad drivers on the 2D road, I want to be far away from the bad drivers on the 3D "road." – Frostfyre Jun 6 '15 at 1:09
• Do we still have steering wheels in this future? that's so obsolete! Oops almost forget about building height limit since many things will be flying around lol. – user6760 Jun 6 '15 at 2:32
• Don't forget terrorism - national monuments have strategically placed concrete benches and the like to prevent anyone driving up to them with a car bomb. Flying cars would require some very creative defense measures. – evankh Jun 6 '15 at 2:57
• @knave are you thinking of AA guns situated on every rooftop reminiscent of black hawk down in Somalia except these are crows lol. – user6760 Jun 6 '15 at 5:35

3D Traffic Reduces Traffic Congestion

If traffic management can be handled, commuters won't be stuck in a traffic jam on the interstates. If there are no pedestrians and no buildings in the aerial traffic lanes, computer control could allow much higher speed. 100 or 200 mph. That means suburbs can spread out even more, and a 200-mile commute is no worse than 20 or 30 miles today.

Flying cars might cause lower buildings.

3D Traffic Replaces Lifts

If those flying cars have smaller danger areas than present-day helicopters, it might be possible to add landing platforms halfway up a skyscraper. One of the limitations on truly tall buildings is the number of lifts, that would be solved.

Flying cars might cause higher buildings.

Once the majority of traffic is in the air, the ground level might be converted into landing/parking spaces. That means all those commuters from the suburbs can find parking spots near their workplace.

Flying cars might replace mass transit.

An Accident Waiting to Happen

As Frostfyre pointed out, flying cars and trucks are even more dangerous than ground cars. That could lead to stronger regulation, like the computer control mentioned by User6760. You can't have an old pickup on the drive that's used every now and then to go to the hardware store. It would have to be a new and regularly maintained/certified pickup instead. If you can't afford that, tough luck.

Flying cars might require more and better mass transit.

When the cops see a broken tail light, they cannot simply stop that air car. That will deprive them of the "opportunity" to spot other suspicious things like DUI. If you believe in the broken windows theory of policing, unpunished minor crimes will lead to major crimes. If you believe that those stops are just a pretext for harassment, that will stop.

The crime rate will go up or down.

Fly-By Shooting

If air cars are under computer control, it becomes harder to use them as a getaway vehicle after a crime. Some criminals might reconsider their plans. On the other hand, it is pretty easy to drop a brick from a flying car. Who can prove where exactly it came from?

The crime rate will go down or up.

• I like these conclusions: Crime rate will go up or down. Flying cars might cause higher or lower buildings. :-) – Mnementh Jun 13 '15 at 5:35
• Flying cars might replace mass-transit... But only if standard ground vehicles can be easily converted into flying ones... And some people just might not like the noise. I think ground traffic may adapt, but not be phased out completely. – Ayelis Jun 16 '15 at 17:55
• This is an amazing example of "I don't know what will happen but here are possibilities." +1 for honesty and comicality. – Josiah Jun 17 '15 at 16:35
• "When the cops see a broken tail light, they cannot simply stop that air car." Why not? The cops would have air cars too. – JAB Nov 16 '15 at 17:48
• @JAB, they would have to escort the offending car to a safe landing spot. That will take time if the traffic lanes are like The Fifth Element or Coruscant in Star Wars. Fewer stops per patrol vehicle per day. – o.m. Nov 16 '15 at 18:10

The social stratification will be based on the available energy usage. Flying cars, jetpacks etc. require a lot of energy (far more than a 2D car or truck of equal weight), and will probably have much lower payload fractions as well for the same size (a lot of the internal space will be filled with engines, fuel tanks, controls avionics etc, while the space needed for rotors, ducted fans or other propulsion devices will be far more than the wheels and suspension of an equally sized ground vehicle. When you compare an air ambulance to a regular one you see they typical 4 litter air ambulance is far larger than a 4 litter ground vehicle). So only very rich people will be able to use air cars on a regular basis.

If only rich people have access to flying vehicles, then buildings may resemble large open boxes, so vehicles can have access to balcony landing pads on the "outside" and "inside" (atrium) surfaces. Very tall, thin buildings would have wind shear and "wind tunnel" issues, so would probably be discouraged as hazards to navigation. The exterior design of buildings would be driven by aerodynamic considerations, preventing wind shear and vortices from forming on the outside or roofs to minimize the possibilities of accidents between the structure and air vehicles coming close by for take off and landing.

If buildings are large "filled" structures, like Arcologies, then the people who do not have access to flying cars will form the second tier of the citizenry, using elevators and people movers to get around the interiors of these huge structures. They will also be deprived of light and access to natural surroundings, unless the builders choose to have atriums and light wells into the interiors. This may happen anyway simply to ensure the structures are light, and provide a larger "honeycomb" structure that suspends the living and work spaces inside.

The third tier of citizens may be the middle class; who have enough wealth to live in suburbs outside of the vertical megastructures and can afford the energy needed to drive 2D cars. They can save up and rent air cars from time to time, or drive to the base of the megastructure and use the elevators and people movers to get around inside and do their shopping, museum visits or whatever they choose to do in the "mega".

So we may see towering "megas" surrounded by rings of middle class suburbs, and the "megas"themselves divided between exterior "penthouse" type dwellings for the supper rich and the interiors filled with smaller, darker spaces where the service and support workers live and function.

We already have a sort of demonstration of this when we suddenly opened up travel from being (generally) foot-bound to the motor vehicle. I.e. suddenly massively opened up the space available for travel in a given time.

Upon invention, congestion will become a thing of the past, briefly. But then, as always, traffic will increase to fill the available space (yes, there might be a lot of it going up but there is still going to be some sort of flight ceiling). Even if "roadspace" is no longer the general constraint, you've still got to park those cars somewhere. Everyone has to start and end a journey, so those become the constraints (were they not already). For a sense of the effect, about 50% of Los Angeles land take is transport infrastructure/parking lots and that's not "solved parking". Where are all these new parking lots going? Even if you build up on parking, you've still got to get into and out of it; think pedestrians near a busy subway or rail station. The basic principles of crowding behaviour apply as much in 3D as they do in 2D.

From the urban design perspective, I don't really think anything changes. We spent half of the 20th Century ploughing highways through city centres and building huge amounts of vehicle infrastructure, only to realise that it's not workable/desirable in the long term and move back to people-scale infrastructure and urban densification with vehicle access restrictions and parking provision restrictions, and a focus on public transport provision.

So, at worst we go through another cycle of that process again. More likely is it becomes an excuse to stop maintaining existing road surfaces which now become pedestrian and cycle routes (and maybe public transport). Vehicle traffic is moved off the surface (up). Access and movement within buildings is still on foot so we aren't abandoning elevators, as a result the primary constraint on general building height still remains. Furthermore, the other main constraint on building height is the value of the space within; nothing about this changes that (if anything the potential for sprawl devalues it).

Assuming the flying cars aren't noisy, I'd say, not a lot changes.

Re jetpacks, I think all of the above still applies but look somewhere like Amsterdam (i.e. for what happens with mass-cycling) for the urban effect (i.e. none) compared to somewhere like L.A. for vehicles.

• I think this answer is pretty comprehensive, and provides insight into many of the issues an Urban Planner is going to have to consider. Though I certainly think that public transport is going to increase, at least, between the office and the aero-garages. – Ayelis Jun 18 '15 at 18:59

Streets would obviously be 3 dimensional. cities would be able to grow up more. the rich could have garages in penthouses. Entry ways could be on every floor. internal stairways and elevators wouldn't be needed.

Hopefully by then the Google self flying car will be the ubiquitous flying car. As such most cars are going to be taxi's that are always on the move shuttling people from one location to another, using optimization algorithms to keep things running efficiently, as such there would be a much smaller need for garages and parking ramps in general.

However, there would likely be parking spaces on the outside of the buildings in especially where views are poor to begin with. with a self parking vehicle (for those rich enough to own one) it can go and find it's own empty parking spot and park. Maybe using a 'smart' parking structure telling it what is available.

Actually, if we assume a gradual shift, cities would change relatively little.

Air traffic moves thru air, not buildings, so it would happen above the city. I assume the end result would be traffic with same speed and direction moving at the same level with some automated air traffic control to prevent collisions, but nature of the air traffic control is not really relevant. Alternately different speeds might travel at different "lanes" within the layer for their direction. This would essentially divide the layers into stripes of different speeds,so you would shift lanes left or right when accelerating or decelerating. Changing layers would happen at the intersection for slow speed lanes where traffic for all layers above and below you would have little or no horizontal velocity. These intersections would also be used drop down to building level or raise from buildings. At building level only minimal horizontal speed would be allowed.

It would be natural to have the jet pack and air cars stored at the top floors of buildings, so roof top garages and landing areas would be built.As such the appearance of the top floors of buildings would change. There would probably be regulations about the height of buildings, such as maximum height, which would be limited to the minimal speed "building level". And in densely populated areas there would be pressure to make all buildings that height to use expensive space effectively.

As more traffic moved to the air, the roads on the ground would be used by cars less, so eventually less area would be reserved for cars and more for pedestrians and recreation. Essentially roads would become narrower and walkways wider. More of the roads would also be restricted from private cars.

• I like the idea of public accessible roof-top entry garages! All those flying cars need to park somewhere. ;) – Ayelis Jun 12 '15 at 22:37
• Though I do doubt that the majority of buildings would change; I doubt most buildings are built with the forethought that something as heavy as a vehicle is going to park on the roof. I can certainly see city carparks changing the layout of their top-levels to accommodate incoming air traffic, however... – Ayelis Jun 18 '15 at 18:55
• @Ayelis You are entirely right. But you can convert a number of top floors to parking space to a reduced number of parking levels so that the rated weight stays same. It is actually easier to convert top floors, which have less weight on them, than basements and such. But I am sure somebody would try to cut corners and simply add the parking space without worrying whether the building can support the mass. That always seems to happen unless building codes are strictly enforced. Mostly I was thinking about buildings designed for air traffic, though. – Ville Niemi Jun 19 '15 at 0:08

To me this spells a split in society like never before.

Flyers literally will look down upon non-flyers. Reality being what it is I foresee a few specialized hubs per country or even continent, for example High New York and High Silicon Valley. Here you have the lifestyle everyone dreams about and few enjoy. It will look like Tomorrowland with extremely high spires, aesthetic architecture, enjoyable little parks and beautiful homes in odd places. Everyone inside being rich safety will be well ensured. Around these hubs life will continue just a bit worse, especially in the shade and fallout of the hubs.

• I can certainly see some of this happening. Hopefully Aerocar Garages have slightly increased security, so disenfranchised pedestrians can't get to the top level to key your skycar. ;) Then again, hopefully there are public personal free socialized skycars for everyone! – Ayelis Jun 18 '15 at 19:08

This is a very good question. There are a few answers to this:

1.) Introducing: the Holo-Street! This goes ten feet above your normal street, and has solid-light handguards so people don't fall off. This time-and-space-saving solution is also stackable, so you can move your streets even higher!

Of course, this means that older cars cannot drive on these streets because they lack the StreetStack Three-Dimensional Manipulation Gear, which allows cars to teleport up and down the streets with safety features designed to keep people from warping into another car!

This one might be a subversion of the question, though.

2.) Blockcars! Cars that are shaped like blocks! Simply put, these flying cars are safe blocks that can easily stack on top of each other, thus allowing congested streets to move upwards and begin to drive on top of the cars below. A cheap, affordable solution to a problematic situation.

• These ideas are quite inventive. Though with cars that drive on top of cars, you might have some of the same problems you'd have with the Conveyor SuperHighway. – Ayelis Jun 18 '15 at 19:03
• Also, I'm not exactly sure how the HoloStreet works. Is it a bridge made of solidified light, like in Portal 2? Or an actual hologram you would fall through? I recognize the manipulation gear from AoT but are you saying pedestrians would need it, or cars would need it? Do the cars actually teleport, or just fly up a level? So confuse! – Ayelis Jun 18 '15 at 19:06
• It's most like the Portal 2 solid light bridges. The manipulation gear is just a product name. It's... literally, just a gear in the axle that allows it to teleport-climb the streetstacks. Literally, just teleport. It'll be like a planar shift, except solely vertical and instant. – Nefer007 Jun 18 '15 at 20:28
• Cool beans! Sounds fun! – Ayelis Jun 18 '15 at 22:10

I think the 'driving' may well be mostly automated (Google will take care of that) due to the inability of humans to deal with the processing of extra spatial information, and that we will probably be wanting to text and jetpacking at the same time (which would be quite dangerous). However, this would depend on how people's attitude towards automated systems turn out in the future.

An alternate and simpler solution might be the simple extension of existing traffic rules and treat it as extra roads and paths that you can only traverse in a very specific manner, in which case it is no more or less complicated than current traffic systems to design and implement.

Another possibility is that traffic will be treated like how people currently solve the problem of colliding into someone else when we are walking in that there are no rules but some loose conventions. Which is to say that there will be a very simple collision detection rule that allows more complex behaviours to form which minimizes accidents.

Most, if not all traffic problems are to deal with human issues. So if you can predict or anticipate human problems then you can deal with it (which is to say that we will probably never be able to).

• Somehow i think that the texting-and-jetpacking-group would soon be handled by the Darwin Award Comittee, and one might argue wether that's good or bad... But it is definitely oone of the problems that solves itself. – Burki Jun 17 '15 at 11:11