Impossible Cities

This paper outlines a design proposal for building car-free cities, circa 2020.

  1. Streets designed for mobility — better design choices
    • This proposal hinges on a re-design of what a city street looks like, to try to get less congestion, twice the average travel speed, and twice the total throughput (compared to, say, Manhattan New York). See chapter 1.
  2. Mobility for prosperity, not for faster commutes
    • The main goal of the new design is to increase urban mobility. However, non-intuitively, the benefit is not faster commutes, but is instead higher wages & more social opportunities, as well as higher land values & better investment return rates. See chapter 2.
  3. Beyond mobility — better cities & better outcomes
    • The main goal is better mobility, but the design has a variety of other potential upsides. Cities like this should be greener, cleaner, fairer, safer, simpler, and more reliable & resilient. See chapter 3.
  4. This matters now
    • This is an important area for study & discussion right now, because there’s about to be a huge influx of urban population, and a huge increase in urban construction. The construction of buildings will happen no matter what, so it would be good to try to do it in conjunction with the construction of modern transportation networks, rather than just repeating what was done in past decades. See chapter 4.
  5. This requires better funding models & better value capture agreements
    • Construction is very expensive. In order to fund the huge amount of construction required for new transportation networks, we need to get much better at land value capture. We need to set up reliable “fiscal engines” that can robustly recover the value created on each development project and reinvest it quickly on the next project. See chapter 5.

Chapter 1 — Streets designed for mobility

The Impossible City proposal hinges on a basic redesign of what a city street could look like.

The Impossible design

The result is:

     
 
2nd Avenue, Manhattan
Impossible Street Design
right-of-way 100-foot wide right-of-way
(including sidewalks & street)		 100-foot wide right-of-way
(including sidewalks & pair of center buildings)
sidewalks two 20-foot wide sidewalks two 15-foot wide sidewalks at ground level
two 25-foot wide “High Line“-style greenways with footpaths
streets one 60-foot wide open-air street two 30-foot wide enclosed streets elevated on 2nd floor
lanes six conventional vehicle lanes
all one-way southbound
each lane 10 feet wide		 eight bicycle lanes
4 northbound & 4 southbound
each lane 6 feet wide, plus two shoulders, each 3 feet wide
vehicles 1 bus-only lane
4 lanes for cars, trucks, taxis, etc.
1 lane parking & curbside loading		 8 lanes for bicycles and bike-sized vehicles
cross-streets about 20 per mile 8 per mile
traffic lights about 20 per mile none
intersections at-grade conventional intersections grade-separated intersections
trees about 150 per mile about 200 per mile
speed limits
as posted		 25 mph1 18 mph
actual speed
average		 7.1 mph for cars2,3
7.5 mph for buses2		 15 mph
vehicle
throughput		 1 bus lane at about 6,000 people per hour (+/- 2,000)
4 car lanes at about 1,000 people per hour each (+/- 400)
1 parking & delivery lane at 0 people per hour
total: about 11,000 people per hour		 8 bike lanes at about 3,500 people per hour per bike lane each (+/- 250 per hour)
total: about 28,000 people per hour
sidewalk
throughput		 about 10,000 people per hour about 10,000 people per hour
bottom line less than half as many people as Impossible City design
each moving half as fast		 twice as many people as Manhattan
each moving twice as fast
  Costs  
traffic fatalities 23 fatalities per million people per year 1 fatality per million per year
CO2 footprint
for transportation
kg per person per year		 1,000 kg 1 kg
cost of public transit
annual dollars per capita		 $360 in fares paid by riders
$720 in city funded transit subsidies
$1,080 total		 $0
private vehicle costs
annual dollars per capita		 $1,000
mostly for cars
about 1 car per 10 people		 $1,000
mostly for bicycles, e-bikes, mopeds, scooters, etc.
about 1 vehicle per person
air quality good really good
noise levels noisier quieter
(see noise)
  Land area & real estate  
roads for cars 17% of land area (2,450 total acres in Manhattan4)  
off-street parking for cars 7% of land area (1,000 total acres in Manhattan4)  
floorspace no real estate floorspace in street 680,000 square feet of floor space per mile

 

Impossible intersection design

Bike-sized vehicles

The Impossible street design replaces cars & buses with a wide variety of different kinds of bicycles & bike-sized vehicles. For this design “bike-sized” means:

  limits for most vehicles limits for licensed cargo vehicles
narrow 30 inch width limit 48 inch width
lightweight 111 pounds or less 222 pounds
underpowered 2 horsepower or lower 4 horsepower
slow 18 mph speed limit city-wide
with automated enforcement		 15 mph
  Examples
  (The copyright to these pictures belongs to their respective owners. The pictures are used here under fair use, and are not included as part of the Creative Commons Zero v1.0 Universal license/waiver that applies to the rest of this paper.)
bicycles bike commuter bmx bike
family bicycles family bicycle family bicycle family bicycle family bicycle
folding bicycles
&
compact hybrids		 halfbike halfbike YikeBike Gocycle Jack Rabbit
electric bicycles Riese & Muller Delite Riese & Muller Roadster
mopeds & scooters
(electric)		 Bird scooter electric scooter two-person scooter sitting scooter Bird sitting scooter
passenger trikes Doohan iTango Doohan iTango Doohan iTango Toyota iRoad Carver Carver Schaeffler Bio-Hybrid
cargo trikes Truck Trike Bakfiets.nl Ester Heavy Load Electric Assisted Cargo Trike Nihola Flex Sanitov's movE Rad Power Bikes RadBurro
cargo vans UPS UPS eav eav FedEx
motor-chairs
&
wheelchairs		 TankChair Speedster Toyota i-real Toyota i-real
hoverboards
segways
ninebots
electric skateboards
etc.		 Ninebot Mini Pro Ninebot ONE S2 Kiwano KO1+
delivery robots Amazon scout brain OS FedEx bot R2-D2

No technology holds as much promise as the humble bicycle—especially when we include its newfangled, electrified cousins—to solve the geometry problem that is getting people short distances around a big city… We don’t need no flying cars. Just give us a place to ride, and watch e-bikes eat everything. 5

Freight

The Impossible City design strives for good urban mobility not just for people, but also for freight shipments and package delivery.

The design constraints for cargo mobility have a lot in common with the design constraints for human mobility, and there’s considerable overlap in terms of what good solutions look like. In the Impossible City design, most packages and cargo would travel on the same elevated bikeway streets that commuters use.

On the bikeway streets, almost all cargo and packages would be carried in narrow, bike-sized vehicles. Cargo vehicles would include human-powered cargo trikes, electric-assist trikes, and fully electric cargo vans, in both 3-wheel and 4-wheel flavors. Self-driving delivery robots could also work well, once that technology becomes reliable and cost-effective.

Cargo trikes and cargo vans are fine for small package delivery, and for tasks involving lots of small items, such as keeping grocery stores and retail stores stocked. Even items as large as sofas and refrigerators are appropriate for small cargo vans.

For larger items, the city needs other alternatives. The Impossible streets are intentionally designed to be large enough to accommodate objects such as standard 40-foot intermodal shipping containers, or the modular mast segments of a conventional construction site tower crane (see video). These wide loads would be the exception, not the rule, because they would take up two or three side-by-side lanes of the bikeway streets, which would inconvenience ordinary commuter traffic. If necessary, the bikeways are also large enough for conventional buses, panel vans, and box trucks.

   
shipping container shipping container
(Copyright KMJ, licensed under the CC BY-SA 3.0 license and GNU Free Documentation License.)

Some oversize items, such as heavy industrial equipment, may be too large to put in shipping containers or box trucks. These items can be transported on ground surface right-of-ways, rather than on the elevated bikeways. The Impossible City design has fewer ground surface right-of-ways, at a wider spacing, and even the ground surface right-of-ways will have a 16’ vertical clearance, identical to the U.S. Interstate Highway standard 16’ clearance.

Emergency vehicles

The Impossible streets are intentionally designed to be large enough to accommodate ordinary fire engines, ambulances, and other emergency vehicles. The city boulevards are painted with lane markings for narrow 6-foot lanes for bike-sized vehicles, but the boulevards themselves are always 4 lanes wide, plus shoulders. The bikeways have an unobstructed width of about 30 feet, and unobstructed height clearance of 14 feet. The entrance and exit ramps are single-lane, but have intentionally been designed to be wide enough for standard emergency vehicles.

Although traditional fire engines can use the boulevards, they may not be necessary. It may be possible for the city to have a larger number of smaller fire-fighting vehicles for different sorts of cargo:

Ideally the Impossible City buildings would all be built with standpipes and fire sprinkler systems, so pump engines and tender vehicles may be less important in an impossible city, allowing the city to instead have more ambulances, hazmat vehicles and rescue vehicles.

A variety of small vehicles can be used for different types of emergency response. These types of vehicles are uncommon here in the United States, but are not a new invention, and are in use elsewhere in the world in places with narrow streets. Examples include:

Foton water tank fire truck

Chapter 2 — Mobility for prosperity, not for faster commutes

The impossible streets & intersections are designed to yield faster travel times and higher throughput, compared to conventional streets in cities like San Francisco or New York.

Beyond a faster commute

You might think that faster travel times would lead to faster commute times, but, surprisingly, that’s usually not the case. Instead, when faster travel is possible, most people choose to use it to travel further per day, instead of using it to travel for less time per day. (See Rules of thumb: Marchetti.)

In practice, the result of faster travel times is not shorter commute times for everyone, but is instead an increase in daily kinematic range for everyone.

Kinematic range

 

Why does kinematic range matter?

Good mobility is more important than it sounds. It’s not just about making rush-hour traffic a little less tiresome. Beyond just convenience, better mobility and kinematic range bring serious changes to the entire metabolism of a city, and to the amount of opportunity and prosperity available to people.

For people, having more destinations within reach means:

For shops, employers, and industry, more kinematic range means:

For 911 calls & first responders, more kinematic range means:

Kinematic windfall

Around the world, larger cities, with their larger kinematic ranges, tend to have higher wages than smaller cities.

As city size increases, when the number of people (and destinations) in the city grows by 100% (meaning a doubling in size), then the economy of the city tends to grow by about 115% (meaning it more than doubles in size), so that there is effectively a 15% “bonus” in per capita economic output for everyone in the city.7

This superlinear growth seems to apply to the whole physical and social metabolism of the city, rather than just the economic aspects of the city. The windfall shows up in statistics about:

“The study finds that when inventors move from a smaller to a large cluster, they experience increases in both the number of patents they generate and the impact of those patents, based on their subsequent citations. For example, a computer scientist who moves from the median cluster to a cluster at the 75th percentile in size would experience a 12 percent increase in productivity, while an inventor in biology and chemistry doing the same would see an 8.4 percent productivity gain. Overall, just a 10 percent increase in the size of a cluster leads to a 0.66 percent increase in the number of patents produced by a top inventor each year.”8

Density & kinematic range

In low-density cities, there are fewer destinations within a given distance, so you have to travel farther to have the same kinematic range as you would in a high-density city. In theory, the low-density city could be less congested, so traffic might flow more smoothly, allowing faster speeds and longer distances in a given amount of time. In some cases it does work out that way, but there’s a lot of variation, and low-density cities may or may not have good kinematic ranges.

Low density cities are susceptible to unfortunate feedback loops. Lower density means more suburban sprawl and longer travel distances, which means more total miles of car trips per day, which means that as the city density decreases, the total number of miles of road (and square footage of road) actually increases. If destinations are no longer close enough to have shared parking, then each destination needs it own parking lot, which takes up more space, which in turn leads to more pressure for even lower density further from the city center, which in turn creates more circulation overhead, more miles of road, and so on.

Cities with high population density may or may not have better kinematic range than cities with lower population densities. If you’re in a city with a high population, that means there are lots of people within a short distance of you, and lots of destinations within a short distance. But kinematic range is about time, not distance. Some very dense cities suffer from serious congestion, resulting in poor kinematic ranges.

The kinematics of existing cities

Larger cities have more total destinations than smaller cities, but some destinations may be too far away for some people to get too. Denser cities have more destinations that are within a shorter distance, but in a congested city, even nearby destinations may take a long time to get to. In practice, different cities have very different kinematics.

Singapore and Dallas-Fort Worth have very different transportation networks, with very different kinematic ranges.

  Singapore Dallas-Fort Worth
population roughly 6 million roughly 6 million
density 20,000
per square mile		 600
per square mile
main mode of
transportation		 mostly public transit mostly cars
time it takes for two people on opposite ends to meet in the middle9 60 minutes 30 minutes
estimated 30-minute kinematic range 25%
of all city
destinations		 75%
of all city
destinations

Improving existing cities

Existing cities, all over the world, have serious traffic congestion problems10,11, despite spending billions on transit projects and on widening roads, in efforts to incrementally improve mobility and kinematic range. As cities grow and economies grow, the congestion problems just get worse.

Cities can improve kinematic range by moving more people or moving people faster

Cities can also improve kinematic range by becoming denser, so that more people and more destinations are nearby

Someday, in the future, cities might also be able to improve kinematic range by using newly invented transit options

Co-location is not the answer

“Co-location” is one tempting approach for trying to improve urban traffic congestion problems. Co-location is the idea arranging places in the city so that people are naturally close to where they want to be, to make it so that they don’t have to go as far to get to the places they want to go.

A real-world example of co-location would be a university or boarding school, where dorms, classrooms, cafeterias, and health-care services have all been placed on a single campus, so that students can do most of the things they need to do without ever needing to leave campus.

In a city with mixed-use zoning, new developments could include a mix of housing, retail, offices, and light industrial space. People, could, in theory, live right next to where they work.

This idea comes up surprisingly often in essays about new urbanism. Unfortuntely, co-location isn’t actually practical in big cities. It would be practical, if each person only wanted to be connected to one “thing”. If all you want is to be at university, then living at the university is practical. Or, if all you want to do in life is go to your job, then living near your office is practical. But in reality, most people are a lot more multi-faceted: they don’t just have a job, they also have outside interests like book clubs & sports teams, and they have people in their life that they want to live with or see often, including parents, children, spouses, partners & friends. Most of these people are connected to other places: their own offices, schools, churches, etc. And each of these people has their own set of connected people, branching into a giant social network. Without severing these connections, there is no practical way to “sort” all the people into geographic regions, so that each person is always living near the places they want to get to.

Co-location in not the answer. Co-location is no substitute for mobility.

Transit vs. cars

Here in the United States, in discussions about urban planning and transportation, many people fall into one of two opposing camps:

In addition to the pro-transit camp and the pro-status-quo camp, there’s also a third camp: people who are optimistic about new technologies for automated, on-demand transportation, like self-driving cars and delivery drones.

Proponents of shared, self-driving cars point to advantages like the greatly reduced need for parking compared to conventional cars, yet the convenience of direct door-to-door routes.

Opponents of self-driving cars point to inherently low throughput-per-lane numbers for cars vs. buses and trains, and the real-world congestion problems that we’re already seeing from on-demand car-share services like Lyft and Uber.

The “Impossible City” design proposal

Given what we know about the cost and throughput of cars, buses, and rail, and given what we know about the emerging new alternatives, what’s the best we could possibly do?

If we could plan a whole urban transportation network from scratch, what’s the optimal mix of different transit modes? Which options are the most affordable, and which ones maximize personal mobility, speedy deliveries, and kinematic range?

What follows is a design proposal for what I believe is a simple, cheap, reliable, low-risk city transportation network that has high throughput, good transit speed, nearly door-to-door convenience, and takes up less space than roads, leaving more land area for parks and buildings.

The Impossible City is just one simple design for a more kinematic city and its transportation network. I’m not suggesting that this is the best design; rather, I’m putting it out as a straw-man proposal, in hopes that it might be a step in the right direction, and that it might spark conversation that leads to better ideas.

The Impossible design calls for:

What would it look like?

A grid

A big grid

With normal buildings

But with sheltered streets

Why is this a better design?

The Impossible design is built entirely around bicycles, bike-sized electric vehicles, and sheltered streets with no intersections. At first blush, it’s hard to imagine that this is a practical design. It doesn’t seem like an entire city could have no buses, trains, or cars, and still manage to move millions of people a day with reduced travel times and increased travel ranges.

It seems impossible, because cars seem like fast, long-range vehicles, and buses and trains seem like high-capacity transit.

Cars truly are fast when they’re on highways, but in cities cars are hugely inefficient and ineffective, requiring huge amounts of lane space per car, and traveling with high burst speeds but poor average speeds.

Buses and trains truly are high-capacity and high-throughput when everyone on them is going from point A to point B. If you have a group of 50 people who are all gathered together (e.g., at a hotel) and who all need to go to the exact same place (e.g., an office or work site) at the same time, then a bus is a wonderfully efficient and effective choice. But in a city, if people are starting from a variety of different places (different apartment buildings on different blocks), and going to a variety of different places (schools, stores, offices), then buses turn out to have quite poor average throughput.

Chapter 3 — Bonus features beyond mobility

If you’re building from scratch, then with a few good design choices it’s possible to build an urban layout that works far better than traditional cities do. New designs can maximize:

(A) Affordability

(B) Blank (this space intentionally left blank)

(C) Conviviality & convenience

(D) Durability, reliability & resilience

(E) Economic prosperity

(F) Freedom, independence & agency

(G) Green sustainability

(H) Health & safety

Affordability

There’s no point in designing a new urban development that is too expensive to build, and no point in building a new urban development that is too expensive for people to afford to move to.

Conviviality & convenience

Significantly increased mobility & kinematic range means that it’s easier to go see people and easier to get to more places. A more mobile city is a city with more social opportunities and social prosperity.

Durability, reliability & resilience

By striving for simplicity, these new designs avoid using lots of “fragile” technologies, like elevators and traffic lights.

Economic prosperity

A city should provide for a good life for the people who live in it and work in it. As described in chapter 2, the Impossible design strives to maximize mobility and kinematic range, with the goal of harvesting a superlinear windfall in wages, wealth, patents, land value, etc. The design is intended to create cities that thrive economically compared to similarly-sized typical cities, with more prosperity, and greener prosperity.

Prud’homme and Lee’s paper, titled “Size, Sprawl, Speed and the Efficiency of Cities,” shows that productivity per worker is closely correlated to the average number of jobs per worker that are reachable in less than 60 minutes. In Korean cities, a 10 percent increase in the number of jobs accessible per worker corresponds to a 2.4 percent increase in workers’ productivity.16

People who live closer to jobs are more likely to work. They also face shorter job searches and spells of joblessness. Proximity to employment proves particularly important to certain kinds of workers and residents. For instance, the duration of joblessness among black, female, and older workers tends to be more sensitive to job accessibility than it is for other kinds of workers. For poor residents, living closer to jobs increases the likelihood of working and leaving welfare. Proximity matters for lower-income, lower-skill workers in particular because they tend to be more constrained by the cost of housing and commuting. They are more likely to face spatial barriers to employment, thus their job search areas tend to be smaller and commute distances shorter. In contrast, higher-income, higher-skill workers, who can afford to commute by car and exercise more choice in where they work and live, have more prospects than just the jobs near their neighborhoods and commute longer distances on average.6

Freedom, independence & agency

A city design should not inadvertently restrict people’s freedoms, limit people’s independence, or obstruct fair access. The Impossible design offers more:

Green sustainability

Compared to a conventional city, the Impossible design should provide:

Health & safety

An Impossible City should be safer and more fun to live in.

How would it compare?

  Proposed Impossible City San Francisco New York
Trips
annual, per million people		 1.2 billion 1.2 billion27  
Commute time
minutes per day
(average per commuter)		 60 minutes 60 minutes 76 minutes
Traffic fatalities
annual, per million people		 1 30 23
CO2 footprint for transportation
annual per capita		 1 kg 2,000 kg 1,000 kg
Commute kinematic range
square feet		 5 billion 1.25 billion  
Kinematic windfall
wages, GDP, patents per capita, etc.		 1.3x 1x  
Proximity to friends
number of neighbors within 15 minutes		 2 million
(without car)		 1 million
(requires car)		  
Proximity to places
number of places within 15 minutes
library, coffee shop, playground, groceries		 2x
(without car)		 1x
(requires car)		  
Proximity to trees
number of trees within 15 minutes		 > 125,000 trees > 125,000 trees  
Cars
per million people		 100 450,000 220,000
Trucks
per million people		 100 60,000  
Buses, etc.
buses, streetcars, light rail vehicles, etc.
per million people		 1 1,380  
Cost to city to subsidize public transit
annual dollars per capita		 $0 $720  
Cost of public transit paid by riders
annual dollars per capita		 $0 $360  
Cost of car ownership
gas, insurance, repairs, payments, etc.
annual dollars per capita		 $0 $4,000 $2,000
Cost of bike ownership
bicycles, mopeds, scooters, segways, trikes, etc.
annual dollars per capita		 $1,000 $100  
Exercise while commuting
minutes per day
(average per commuter)		 15 minutes
(if 3 of 4 bikes
are e-bikes)		 5 minutes  
Air quality really good good  
Noise levels slightly lower than
San Francisco22		 slightly more than
proposed city		  
ADA accessibility
percent of total city floor space		 90% ?  
Free-range kids yes no  
Power-outage impact
on transit times		 no bikeway lights
(just daylight/moonlight)		 no BART
no traffic lights		  
Daylighting
Spatial Daylight Autonomy (sDA) percent
Annual Sun Exposure (ASE) percent
(also several others)		      
Home sizes
square feet per person, average		 275 275  
Office space
square feet per person, average		 260 260  
911 response time
minutes, average		 4 minutes 5.75 minutes  

Chapter 4 — Why this matters now

Figuring out how to design better cities is especially important right now, at this moment in history, for a few reasons.

There’s no way to cheaply or practically re-build existing cities, or move people en masse from existing cities to new cities, but, when new cities, new suburbs, and new satellite developments are being planned and built from scratch, it would be slightly crazy to fail to try designing them as “kinematic cities”. Building from scratch has its own challenges, and is also crazy expensive, but it does have the advantage that it can be done much more quickly.

The Impossible design does not depend on a particular climate, or on particular building materials. It’s an anywhere-in-the world city, not just a European city, an African city, or an Arctic city. It could be built on the outskirts of an existing city, or it could be built in a brand new “greenfield” site.

“If you build a new city you don’t have to relocate or work around existing roads or rivers or factories or houses. You also don’t have to work around existing political processes, community groups, civic organizations … or even existing regulations and rules.”28 — John Macomber, senior lecturer, Harvard Business School.

Urban population boom

In the next 30 years, by 2050, urban population is expected to grow by 60%, with another 2.5 billion more people living in cities.28

Year Urban
portion
of world		 Total urban population29
1950   0.75 billion
2018 55% 4.2 billion
2050 68% 6.7 billion

Perhaps existing cities will absorb nearly all of the 2.5 billion additional people who will live in cities by 2050, but in doing so some of their suburbs will essentially develop into big satellite cities of their own right. The Impossible City ideas are relevant for how new developments in those satellite cities are designed. If 4% of those 2.5 billion additional people did move to entirely new urban developments, that would be 100 million people in new urban developments.

Urban construction boom

Existing cities are too few and too small, by a factor of two, for everyone who will live in them by 2050. To handle the influx, cities will build another 2.5 trillion square feet of new buildings. These numbers can be hard to believe at first. For different projects by different authors, see the notes about urban growth below.

This wave of construction is going to happen no matter what, whether we prepare for it or not. People will build housing for themselves, even if they can’t do it legally, in slums and informal settlements like those in Kibera, Dharavi, Neza, and Orangi Town. If we could muster more planning, forethought, and funding, then these new developments could end up with infrastructure like comprehensive sewer systems and high kinematic-range transportation networks.

“If we stick to business as usual most of it is going to be disorderly and less functional than the stuff we already have.”28 — Paul Romer, Nobel prize-winning economist, New York University.

“Megacity” urban agglomerations

Currently, the world has about 33 “megacities”, where a megacity is defined as an urban agglomerations with more than 10 million inhabitants. The world is projected to have 43 megacities by 2030, and about 50 megacities by 2050, with an additional 125 large-but-not-mega cities that land in the range between 4 million and 10 million inhabitants.30

City clusters already exist of course, like the Randstad in the Netherlands, which links Amsterdam, Rotterdam, The Hague, and Utrecht. The urban development around San Francisco Bay could also be considered a city cluster. What is different with the Chinese concept of cluster is their scale. The Randstad connects only 7 million people, while San Francisco Bay (including Silicon Valley) has only 6.2 million people. By contrast, the urban cluster of the Pearl River Delta already had 65 million people in 2010, larger than the entire population of the United Kingdom but concentrated on less than 10,000 square kilometers! The recent urban cluster including Beijing-Tianjin-Hebei links together more than 105 million people.16

Kinematic lag

Kinematic range generally increases as cities get bigger. I believe that increase in kinematic range is what drives the superlinear scaling effect.

As a city grows, at first, kinematic range increases as population increases, perhaps in a roughly linear relationship. Unfortunately, as cities get too big, they start to sprawl and suffer from traffic congestion. Eventually, there’s a kinematic lag, where the kinematic range stops its 1-to-1 tracking of population growth, and begins to lag behind.

This whole Impossible Cities proposal is all about trying to reduce that kinematic lag in larger cities. The proposed Impossible City design is an attempt to keep increasing a city’s kinematic range even as its population grows in the multi-millions.

As the world adds more and more large cities and megacities, kinematic lag becomes a bigger and bigger problem, kinematic range becomes more important, and design ideas like the Impossible City design become more important.

 

“Contrary to common perception, megacities have not been driving global growth for the past 15 years. In fact, many have not grown faster than their host economies, and we expect this trend to continue. We estimate that today’s 23 megacities will contribute just over 10 percent of global growth to 2025, below their 14 percent share of global GDP today. Instead, we see the 577 fast-growing middleweights … contributing half of global growth to 2025, gaining share from today’s megacities. Worldwide, we will see 13 middleweight cities become megacities by 2025.”31

Lost opportunities

Take the San Francisco Bay Area as an example. The Bay Area is a conurbation that encompasses major cities like San Francisco and San Jose, as well as lots of smaller cities, like Oakland, Berkeley, and Mountain View. The entire population is about 8 million people, depending where you draw the boundaries.

If you estimate floorspace at about 600 square feet per person, that means there’s about 5 billion square feet of floorspace in the Bay Area. Your thirty-minute kinematic range (KR30) would be 5 billion square feet, if you could magically get from any point in the area to any other point in under 30 minutes. But you can’t.

As a rough estimate, let’s say that from any room in any random building in the Bay Area, within 30 minutes you can reach about one quarter of the other buildings in the Bay Area. That means your actual 30-minute range would be about 1.25 billion square feet.

If we could just improve your travel times enough, we could quadruple your KR30 range. If kinematic range is in fact what drives the superlinear scaling effect, then doubling the 30-minute range for the Bay Area would yield a 15% windfall in average hourly wages, patents per capita, GDP, etc. Doubling the 30-minute range gets you a 15% windfall, and quadrupling gets you a 30% windfall (actually more like 32%, because 1.15^2 is 1.3225).

GDP. The San Francisco Bay Area GDP was about $535 billion in 2019.32 A 30% annual increase would be an additional $160 billion annual GDP.

Real estate. The San Francisco Bay Area has about $1.3 trillion of residential real estate. A 30% increase in value would be a $400 billion increase, just for the residential portion of the real estate. Commercial real estate would be roughly another $400 billion. There would also be additional floor space in the roadway buildings, which might amount to another $200 billion, for a total of about $1 trillion of additional real estate value. San Francisco is one of just a few cities in the United States that has a market value higher than the $1 trillion Apple Inc. value.33 But other cities have even higher real estate values. In New York City, the housing alone is worth $1.5 trillion. In the Upper East Side, housing value has reached $100 billion per square mile.34

Hope? I’m not suggesting that anyone could somehow re-build the San Francisco Bay Area to quadruple kinematic range, but I am saying that hypothetically, if the Bay Area had been built kinematically to begin with, then the real estate would be worth $1 trillion more than it is now. In the case of the Bay Area, that’s $1 trillion in real estate value that somehow got left on the table: value that was lost just because of past choices about streets, geometry, and buildings.

Is it conceivable that the Bay Area could be re-engineered to quadruple travel ranges? Yes, but it would require a lot of changes: maybe a hyperloop, or a lot of Boring Company tunnels. It would be expensive, and it would take decades. The Bay Area has already calcified, and for all practical purposes, big changes now are pipe dreams. For context, here are a few examples of the giant cost of modest mobility improvements:

Current opportunities, GNP

As of 2017, the worldwide gross national product (GNP) was about $80 trillion per year. Some of that GNP comes from rural activities, like farming, and other remote activities, like mining and fishing. But the majority of GNP, more than 80%, comes from urban areas, for a total of about $65 trillion per year.31,35

By 2050, global GNP will probably roughly double, to about $160 trillion per year. By 2050, more than $140 trillion of that total is likely come from the urban areas.

Some of those “urban areas” are actually small towns with just a few thousand people, but increasingly, the majority of the urban population will be living in larger and larger cities, and those large cities also generate a disproportionately high amount of the total GNP. By 2050, about 16% of the world’s population, 1.6 billion of the world’s 9.8 billion people, will be living in the world’s 175 largest cities, with 4 million to 40 million people each.30 A conservative estimate suggests those 175 cities will contribute $30 or $40 trillion per year to worldwide GNP.

Because of their size, all of those 175 cities will probably suffer from kinematic lag. If we could intervene, and by 2050 we could somehow double the kinematic range in each of those cities, we could expect to yield a 15% kinematic windfall on the GNP from those cities. A back-of-the-envelope calculation suggests that would be an ongoing windfall of maybe $4 trillion to $6 trillion per year in increased GNP. Other authors give significantly higher values for annual return in increased GDP from urbanization:

In Africa “we should be building 40 million new homes or 160 Atlantas every year. … Africa has 54 countries. Altogether they do not build 1 million homes a year. The gap is the opportunity. 40 million modest homes require an investment of more than $1 trillion every year. The multiplier effects would add $10 trillion to annual GDP. That is 5 times current GDP. Closing Africa’s housing gap can generate 5 times current GDP!” — Paul Musembwa, CEO of Warp Developments

In a paper published in 2015, the economists Chang-Tai Hsieh and Enrico Moretti found that, between 1964 and 2009, the high cost of housing in some US cities relative to wages had lowered aggregate US GDP by 13.5 percent: “Most of the loss was likely caused by increased constraints to housing supply in high productivity cities like New York, San Francisco and San Jose. Lowering regulatory constraints in these cities to the level of the median city would expand their work force and increase U.S. GDP by 9.5%.16

Current opportunities, land value

In the San Francisco Bay Area, the total residential and commercial real estate is worth about $2.6 trillion.

The total value of all real estate, worldwide, was about $280 trillion at the end of 2017. Of that total, most is residential real estate, at $220 trillion, with just $33 trillion of commercial real estate and $27 trillion of agricultural real estate. Worldwide, residential real estate is worth more than all of the equities & debt securities combined. 36

In Manhattan, land value grew at an annual rate of 5.5 percent beyond inflation 1950 to 2015.37 That’s an unusually good return, but in general real estate value has increased at roughly the same pace as GNP. By 2050, total worldwide real estate might be worth about $560 trillion.

By 2050, the world’s 175 largest cities will have residential real estate worth more than $100 trillion. If we could double the kinematic range in those cities, we could expect to yield a 15% kinematic windfall, for maybe a $15 trillion increase in residential real estate value. Unfortunately, trying to double the kinematic range of even a single city is probably impossible.

In a world where another 2.5 billion people will be moving into cities in the next 30 years, we should think twice about how much prosperity we want to leave on the table. Real estate developers who care about the value of their land should care about building kinematically. And it’s not just real estate. It’s also hourly wages, GDP per capita, and patents per capita. Our current cities are sub-optimal to the extent that there are hundred of billions of dollars of lost value per major city. Anyone, or any coalition, who can optimize on that can begin to harvest that windfall. In practice, the windfall would get split up between lots of different parties, with enough incentives to go around.

There would be:

Chapter 5 — Why this is impossible

We know that:

Unfortunately, actually building cities this way is probably impossible, because of:

Location problems

These new urban development designs could be built in a few different types of locations, but they all have problems:

Network effect problems

Depending where construction happens, the Impossible Cities design faces one of two different network effect problems.

Cost problems

Constructing even small buildings is expensive. Constructing entire neighborhoods or entire cities requires not just building housing and office space, but also building all the transportation infrastructure for roads, street lights, traffic lights, bus shelters, subway stops, and more. Plus all of the utility infrastructure, including sewers, water supply, power lines, telephone lines, and the rest.

Bootstrapping problems

The problem of how to minimize upfront costs comes down to a bootstrapping problem, and amounts to a chicken-and-egg problem. A new city project doesn’t actually have to build a huge new city over night, but how do they create a minimum viable seed that’s large enough to spin up enough economic activity to propagate its own growth?

At a minimum, it seems like the project founders would need to:

Building even a small seed of an Impossible City would take a long time and lot of resources. A minimum viable start might need:

Land value capture problems

Building good urban infrastructure, including transportation infrastructure, is extremely expensive. But in a city with good transportation infrastructure, the value created by the transportation infrastructure far exceeds the cost of the infrastructure.

“With the right framework, astonishing prosperity is possible. The independent city of Singapore overtook the world’s GDP per capita in less than 30 years, and that of the USA in less than 50 years.” 47

Possible vs. Impossible

  Possible Impossible
Vehicles needed
(existing)		  
Construction technology
(existing)		  
Location problems  
Network effect problems  
Cost problems  
Bootstrapping problems  
Land value capture problems  

FAQ, etc.

FAQ: Frequently Asked Questions

Could we build an Impossible City?

Yes. The Impossible City plans are designed with existing technology in mind, and with an eye toward simple, affordable technologies. It’s about bicycles and water pipes, not about floating ocean domes and orbital towers.

Where could we build an Impossible City?

Anywhere. The Impossible City design would work equally well in either low-income countries or high-income countries. The design would also work in any of the wide range of climates where existing cities are located. Here are some ideas about Hypothetical locations.

How much would it cost to build an Impossible City?

A fortune. In a high-income country, building construction costs might be something like $300 per square foot, with perhaps 600 square feet per person. So that’s about $200,000 per person, just for the construction of buildings, not counting land purchase costs, and not counting construction costs for infrastructure like sewers, dams, reservoirs, water treatment plants, airports, etc. Even in a low-income country, mid-rise building construction costs are likely to be at least $30 to $50 per square foot, with perhaps 150 square feet per person. That comes to at least $7,500 per person just for the construction of homes, shops and workplaces, not including land purchase and infrastructure construction.

How many people would live in an Impossible City?

Anywhere from 50 thousand to 50 million people. The Impossible City would work fine for a wide range of city sizes. The design does not make sense for small towns or villages, because the transportation system overhead is overkill for a town without any traffic problems. For cities of 50,000 or more the Impossible City design might offer some advantages over conventional designs. The Impossible City design begins to shine for cities of 4 million or more, offering better kinematic ranges than conventional cities. Impossible Cities with tens of millions of people would work well too, although they would need to also include subway systems or light rail systems.

How much indoor space would people have?

A normal amount, but not cavernous mansions. An Impossible City in California could have about the same amount of space per person as does a city like San Francisco, at roughly 600 square feet per person. An Impossible City in India could have an amount of space typical for that region, perhaps 150 square feet per person. But an Impossible City could not have a lot of cavernous mansions with thousands of square feet per person, because the transportation system would not work at those low population densities.

How much green space would people have?

A typical city amount, but not a typical suburban amount. An Impossible City in California could have about as much green space as does a city like San Francisco. But an Impossible City would not have single family houses each with their own front and back yards.

Could we turn London or Paris into an Impossible City?

No. Existing cities have a lot of physical infrastructure that’s expensive to change. People can make incremental changes, like adding new roads or bridges, but it’s not practical to change the fundamental layout and transportation network of an existing city.

Could Impossible City ideas trickle down to existing cities?

Yes. Over time people in existing cities like New York and San Francisco could adopt some of the ideas in the Impossible City designs, and make their cities incrementally more kinematic, even if they can’t change the fundamental layouts. One “simple” change would be re-stripe some of the lanes on some of the roads so as to split an existing automobile lane (at, say, 12 feet wide), into two side-by-side bicycle-sized vehicle lanes (at, say 6 feet wide each).

Do Impossible City ideas impact democracy and governance?

No. The Impossible City designs are politically neutral. The designs are only about transportation systems and about the physical, spatial layout of the buildings in the city.

An Impossible City could have a traditional city government structure, or it could experiment with less conventional structures. That’s a big topic, and one for another author. Suffice it to say, the questions of governance are largely orthogonal to the ideas presented here about the physical layout of a city, the transportation choices, etc. An authoritarian government could build an Impossible City, or a utopian libertarian collective could build an Impossible City, and they would both be Impossible Cities.

Rules of thumb

City Population Average Hourly Wage
(this is not actual observed data,
just example numbers)		 Superlinear Scale Factor
40,000 $16 (-15%)^4 below $28
80,000 $18 (-15%)^3 below $28
160,000 $21 (-15%)^2 below $28
320,000 $24 -15% below $28
640,000 $28 100% average
1.25 million $32 +15% above $28
2.5 million $37 (+15%)^2 above $28
5 million $43 (+15%)^3 above $28
10 million $49 (+15%)^4 above $28

Economic literature linking the wealth of cities to spatial concentrations is quite abundant and is no longer controversial in academic circles. … The 2009 World Bank Development Report “Reshaping Economic Geography,” and the report of the Commission on Growth and Development “Urbanization and Growth” (published the same year) exhaustively summarize and document the theoretical and empirical arguments justifying the economic advantage provided by the spatial concentration of economic activities in large cities.16 — Alain Bertaud

“High-tech invention is extraordinarily concentrated in just a handful of cities. … The top 10 city-regions account for nearly 60 percent of inventors in biology, chemistry and medicine, with greater New York and the San Francisco Bay Area accounting for more than 10 percent each. Seventy percent of inventors in computer science are in the top 10 regions; the Bay Area alone has more than one-quarter of them. And the top 10 regions account for almost 80 percent of inventors in semiconductors, with one-quarter again in the Bay Area and another 15 percent in greater New York.” … “This clustering of inventors has only increased over time, growing by about five percentage points for biology, chemistry, and medicine, 15 percentage points for computer science, and about 20 percentage points for semiconductors between 1971 and 2007.”8

Effective altruism

Effective altruism is the idea of trying to find the most cost-effective interventions for improving global well-being, and then directing money and resources towards those efforts. Non-profit research organizations like GiveWell(link) work hard to evaluate wide arrays of possible interventions and try to find the most effective ones. Private foundations like the Gates Foundation have similar internal research departments.

The idea of building Impossible Cities might be worth studying as a candidate intervention for effective altruism. Building cities is far more expensive than most philanthropic interventions, but it also has the potential for a variety of simultaneous large-scale positive outcomes.

Appendixes

Books & software

Books

Software Tools

Glossary

<= more common     vs.     less common =>

Hypothetical locations

Just as a thought experiment, it can be interesting to look at regions of existing cities and think about which places might be large enough to sustain a new car-free kinematic district…

Treasure Island, near San Francisco

Question: Would a site like Treasure Island (including Yerba Buena Island) be a suitable test site for a new neighborhood with an Impossible City design? It’s about 2.5 square kilometers, but currently only has a population of about 2,500?

Answer: No, Treasure Island is too small. Also too remote – being entirely surrounded by water is a loss in terms of commute times and ranges. Ferries are slow. Cars are subject to all the existing traffic congestion. A BART extension would cost billions, and perhaps tens of billions. Potentially that BART extension alone would be more expensive than an entire seed neighborhood on a 50-square mile greenfield site.

Treasure Island would certainly have huge market demand. Every apartment you built would rent for thousands of dollars a month. But buying all the land on Treasure Island, at market prices, would cost you billions. And construction costs would be $500 per square foot, so even once you owned the island, it would still cost $400,000 per apartment to build housing. If you built office space too, and high schools, and police stations, pretty soon you’ve got a construction budget up over ten billion for this “small scale” starter project!

In contrast, buying 50 square miles in a satellite location on the outskirts of a city in Africa could be relatively affordable, and you might be met with a warmer welcome in the whole multi-year design review & permitting process.

Brisbane, California

Brisbane Baylands would be a better site than Treasure Island. The city of Brisbane, just south of San Francisco, does have a large undeveloped parcel that would be big enough to build a bit of an Impossible City in.

Brisbane Baylands has slightly more land area than Treasure Island, and there’s no new construction work already underway like Treasure Island has. Plus the Caltrain commuter train and highway 101 run right through Brisbane Baylands, and a Muni light rail station is there. It’s also immediately adjacent to San Francisco, with no bridge crossing or ferry required.

Brisbane Baylands already has a private land owner and private developer that want to build on it. It could be a great location for a kinematic district, but only if the voters in Brisbane wanted denser development, which they don’t.

Stanford University, California

The Stanford University campus, at 13 square miles, is more than an order of magnitude larger than Treasure Island and would be a candidate for a new Impossible City district. It’s also already situated in a developed urban area, with good connectivity to highways 101 and 280, Caltrain, and two existing international airports. And, unlike Treasure Island, it’s not surrounded by water, which means all the area immediately around it falls into its kinematic range.

But for Stanford to work as a location, people would have to be willing to tear down some of what’s already built there. And the whole project would only be possible in some very like scenario where the city of Palo Alto were willing welcome hundreds of thousands of new neighbors, with all the strain that would bring on already congested highways, airports, and train lines.

Other San Francisco Bay Area sites

There are other sites all around the Bay Area that are big enough and well located, if it were possible to get approval to build densely on them. Half Moon Bay, Pescadero, or, oddly, the huge empty space right in middle of the Bay itself, north of the Dumbarton bridge and south of the 92 bridge, which in many ways would be nearly perfect, except for the fact that construction in the Bay is completely off limits, given its status as a protected nature reserve.

The Sea Ranch, California

Further afield, there’s the Sea Ranch. It has more land area than the Stanford Campus, but with a population of only 1,300 people, so there is only a small pool of existing owners to buy out, and a small number of buildings to be moved, removed, or incorporated into the new plans. The weather is great, the views are great, the hiking is great. But it’s remote: it’s only got a tiny airport, and no port, no rail, no major highway. I think it would only really work in some science fiction scenario where you could build a hyperloop tunnel to San Francisco and Silicon Valley.

Northern California Coast

There are other similar sites up the California coast, like in the Eureka area, with similar pros and cons. Or the area around the Little River Airport by Mendocino, if the State of California suddenly decided to allow development in the State Park property.

The Northern California Coast is one of a number of unusual places in the world. For some sorts of development projects, it might prove to be a “Goldilocks” location, with a rare collection of attributes:

Greenfield locations

Alternatively, instead of looking at locations in places like California, it might be easier, faster, and more fruitful to work with people who are already in the process of planning large new developments on open greenfield sites, the way people are doing in Asia, Africa, and the Middle East.

Fast-growing locations

The best locations might be ones that are close to the cities that are expected to grow the most dramatically in the coming decades and have very large populations by 2050:

City 25-year
growth
projection		 25-year
growth %		 2050 population
projection 30,60		 2025 population
projection 60
Kinshasa, DRC 18 million 109% 35 million 17 million
Lagos, Nigeria 17 million 107% 33 million 16 million
Mumbai, India 16 million 61% 42 million 26 million
Delhi, India 14 million 61% 36 million 23 million
Dhaka, Bangladesh 13 million 60% 35 million 22 million
Karachi, Pakistan 13 million 66% 32 million 19 million
Kolkata (Calcutta), India 12 million 61% 33 million 21 million
Dar es Salaam, Tanzania 10 million 181% 16 million 6 million
Kabul, Afghanistan 10 million 138% 17 million 7 million
Manila, Philippines 9 million 59% 24 million 15 million
Cairo, Egypt 8 million 54% 24 million 16 million
Nairobi, Kenya 8 million 143% 14 million 6 million
Khartoum, Sudan 8 million 102% 16 million 8 million
Baghdad, Iraq 7 million 87% 15 million 8 million
Chennai (Madras), India 6 million 61% 16 million 10 million
Lahore, Pakistan 6 million 53% 17 million 11 million
Luanda, Angola 6 million 74% 14 million 8 million
Bangalore, India 6 million 61% 16 million 10 million
Hyderabad, India 6 million 61% 15 million 9 million

Impossible City design summary

Transportation

The Impossible City design calls for:

Instead, the design has:

Spatial layout proposal

A Impossible City design has:

Instead, it has:

Ramp proposal

Optionally, an Impossible City could have:

In this scenario, the only way to go “upstairs” or “downstairs” in an Impossible City would be by using:

The idea of having no stairs and no elevators sounds crazy to most people when they first hear it, because it’s so different from all the normal buildings and cities that we’re used to.

However, if you run the numbers, and run simulations, it turns out that getting rid of elevators and stairs works out just fine. Instead of making it harder to get places, having no elevators makes it faster to get between any two random locations.

The Impossible City ramp-only design:

Safety proposal

An Impossible City could have:

Instead, it would have:

Source material, chaper 1

Throughput per lane (source: NACTO63)

Throughput Width Mode
people per hour    
600 to 1,600 one lane, 3 meters wide private motor vehicles
1,000 to 2,800 one lane, 3 meters wide mixed traffic with frequent buses
6,500 to 7,500 one lane, 3 meters wide two-way protected bikeway
4,000 to 8,000 one lane, 3 meters wide dedicated transit lanes
8,000 to 9,000 one lane, 3 meters wide sidewalk
10,000 to 25,000 one lane, 3 meters wide on-street transitway, bus or rail

Throughput per lane (source: Bertaud16)

Throughput Vehicle type
passengers per hour per lane
at about 15 km/h		  
1,000 Bus, M1: 5 minutes headway
1,600 cars
2,600 Bus 4 routes: 1 minute 48 seconds headway
2,800 motorcycles
5,500 bicycles on entire lane width

Width per 10,000 throughput (source: NACTO64)

Throughput Width Mode
people per hour    
10,000 one lane, 12’ to 15’ wide sidewalk
10,000 one lane, 12’ to 15’ wide protected bike lane
10,000 two lanes, totaling about 23’ wide bus-only lanes, with 80 buses per lane per hour
10,000 13 lanes of conventional arterial, at about 156’ wide mostly cars, with 800 vehicles per lane per hour

Car speeds

“cars in the busiest parts of Manhattan now move just above a jogger’s pace, about 7 m.p.h., roughly 23 percent slower than at the beginning of the decade.” 3

Pedestrian speeds

“the average human walking speed at crosswalks is about 5.0 kilometres per hour (km/h), or about 1.4 meters per second (m/s), or about 3.1 miles per hour (mph). Specific studies have found pedestrian walking speeds at crosswalks ranging from 4.51 kilometres per hour (2.80 mph) to 4.75 kilometres per hour (2.95 mph) for older individuals and from 5.32 kilometres per hour (3.31 mph) to 5.43 kilometres per hour (3.37 mph) for younger individuals” 65

    Walking
speeds
per
horizontal
distance67		      
Stair
gradient		 Grade Up stairs Down stairs Up stairs Down stairs
(degrees) (rise:run) over 50 age 30 to 50 over 50 age 30 to 50
38.8 80:100 0.435 m/s 0.485 m/s 0.47 m/s 0.59 m/s
35.0 70:100 0.515 m/s 0.565 m/s 0.585 m/s 0.645 m/s
30.5 59:100 0.58 m/s 0.635 m/s 0.64 m/s 0.74 m/s
24.6 46:100 0.72 m/s 0.76 m/s 0.80 m/s 0.865 m/s
32 62.5:100 0.41 m/s 0.60 m/s 0.52 m/s 0.60 m/s
27 51:100 0.43 m/s 0.73 m/s 0.58 m/s 0.73 m/s 
tan(27 degrees) = 0.51 => 51% grade = 51 foot rise per 100 foot run

0.73 m/s horizontal on 27 degree stairs => 0.37 m/s vertical = 1.22 feet/sec vertical

CO2-e emissions

CO2-e emissions16 Vehicle type
grams per passenger km  
151 average US car
26 Nissan Leaf in California
5 Nissan Leaf in Sweden
67 New York subway
180 US urban bus

Noise

“…the population in Wuhan is 8.3 million, much greater than that in Sheffield, at 0.6 million. … For Wuhan, given that the number of vehicles per person is still much lower than that in Sheffield by tenfold … it is very interesting to note that the average noise levels in all of the sampled areas are lower than those in Sheffield by 2dBA to 11dBA. … In terms of Lmin and L90 … the difference is even greater – for example, up to 15dBA in the area with a motorway.”22 — Jian Kang

Density

People per
square mile		 City Land area
square feet
per person
85,829 Central Paris68 325
78,874 Impossible City Proposal
(density of city districts, sans greenbelt)		 353
71,340 Manhattan, New York69 391
68,376 J.H.Crawford’s Carfree Cities Reference Design
(density of city districts, sans greenbelt)68		 408
52,593 Paris70 530
27,751 New York City71 1,005
18,838 San Francisco72 1,480
10,117 J.H.Crawford’s Carfree Cities Reference Design
(combined density of city districts and greenbelt)68		 2,756
10,101 Suburban single-family housing68 2,760
  For more examples of city densities, check out DensityAtlas.org.  

Floor area ratio

FARparcel FARoverall Place  
0.316   US suburbs  
  0.41 San Francisco  
~ 1.7 Proposed Impossible City  
3.516   Historical Paris  
4 to 1016 3 to 773 Manhattan residential  
1516 10 Manhattan office buildings  
2516   Singapore highest FAR  
    For more FAR examples, check out DensityAtlas.org.  

“urban planners historically focused on residential travel and personal behavior, failing to integrate the movement of goods into their planning.” 74

Source material, chaper 2

Kinematic range

Kinematic windfall

“Third, the clustering of high-tech inventors brings real benefits to the American economy as a whole. … [Enrico Moretti] estimates that the U.S. would produce about 11 percent fewer patents each year under such a scenario. The country would see a roughly 15 percent annual decline in semiconductor patents, a 13 percent decline in computer science, and a 10 percent decline in biology and chemistry, if the geography of inventors was more equal.”8

Bicycles

We see that bicycles provide a much higher road capacity at speeds below 15 km/h than any other mode of transport.16

Because of their higher speed and increased comfort, electric bicycles, where they are authorized (as in Chengdu, China), could meaningfully compete with buses or cars as a means of commuting in larger cities.16

The emergence of small footprint, on-demand, shared vehicles … will change the way urban transport is organized. The pattern of roads and arterials may also change to adapt to these new modes of urban transport. Instead of concentric traffic on a few high-capacity highways or arterials, numerous smaller low-capacity roads would allow the flexibility required by trips from dispersed origins to dispersed destinations.16

Small cars

By contrast, compared to the motorcycle, compact Smart car performance (except for energy use) in terms of road capacity is not much better than that of an ordinary car. … The width of the vehicle, not its length, is the important parameter to consider when trying to reduce street area consumption.16

Congestion

“In a study last year, Inrix estimated that the cost of congestion in the United States alone was $305 billion (USD)” 10

“In L.A., nothing concerns locals more than traffic—not personal safety, the cost of living, or even the housing market—according to a 2016 poll by the Los Angeles Times. Drivers there spend an average of 80 hours in gridlock every year, according to a report by Texas A&M University.”11

Source material, chaper 3

Affordability

“Above six storeys, significant extra costs are incurred in sprinkler systems, and after ten storeys, the need for enhanced fire escape provision means that the extra costs can only be recouped if storey heights push up above 15 storeys.”13 — Susan Roaf

“For five Melbourne office buildings of the following heights: 3, 7, 15, 42 and 52 storeys, the two high-rise buildings were found to have approximately 60 per cent more energy embodied per unit gross floor area (GFA) in their materials than the low-rise buildings.”13 — Susan Roaf

Height
in stories		 GJ per square meter
gross floor area13
3 10.7
7 11.9
15 16.1
42 18.0
52 18.4

“In addition, there are higher operation and maintenance costs in taller buildings…”13 — Susan Roaf

Parks & trees

“Meyer-Lindenberg is currently tracking how different parts of the city affect our mental wellbeing, using a technique called ecological momentary assessment, in which participants repeatedly report on the environment around them in real time. Various studies have suggested that nature – be that a tree or a park – has an important impact on people’s mental health.”23

“Studies have consistently linked city living with poorer mental health. For example, growing up in an urban environment is correlated with twice the risk of developing schizophrenia as growing up in the countryside.”23

“Mental health is almost uniformly worse in cities… that’s just what the data shows,” [Andreas] Meyer-Lindenberg says over the phone. “There isn’t really a bright side to this.”23

Resiliency

“Resiliency is the ability to bounce back better, but also the ability to not have to bounce back as much.” — Sylvester Wong, Vice President of AECOM76

“Because its location and design were deliberately chosen to withstand natural calamities, New Clark City will serve as the government’s continuity hub, disaster and risk recovery center – an alternative capital city in case a disaster strikes Manila”76

Source material, chaper 4

Global urban growth

“Half of the urban area that will be needed [by 2050] hasn’t been built yet.”28

“Over the next 40 years, the newly built floor area in the world is expected to double.”77

“We’re going to develop more urban area in the next 100 years than currently exists on Earth”28 — Paul Romer, Nobel prize-winning economist, New York University.

“The amount of floorspace in buildings around the world—currently about 2.5 trillion square feet—is set to double by 2060” — Brian Bienkowski 78

It is estimated that by 2050:

“This will be by far the largest migration of human beings to have ever taken place on the planet … The resulting challenges to the availability of energy and resources and the enormous stress on the social fabric across the globe are mind-boggling … and the timescales to address them are very short.”7 — Geoffrey West

“The UN estimates that each year cities across the world will gain more than 72 million new residents.”84

“averaged over the next thirty-five years, about a million and a half people will be urbanized each week … the equivalent of another New York metropolitan area [every two months]”7

120 “new cities” are currently being built, in 40 countries.38 These developments are frequently called “new cities”, although often they are more like new suburbs or new satellite neighborhoods of existing cities, rather than brand new cities in their own right.

“China … is on a fast track to build up to three hundred new cities each in excess of a million people over the next twenty to twenty-five years. … At the present rate it will be moving the equivalent of the entire U.S. population (more than 300 million people) to cities in the next twenty to twenty-five years.”7

“India, for example, will be home to 7 cities with populations greater than 10 million residents by 2050.”84

“projections show that Kinshasa, the capital of the Democratic Republic of Congo, will reach 35 million residents by 2050.”84

California urban growth

In California alone, “to satisfy pent-up demand and meet the needs of a growing population, California needs to build 3.5 million homes by 2025.”85

“Broadly speaking, there is no solution to the California housing crisis without the construction of millions of new houses,” said David Garcia, policy director for the Terner Center for Housing Innovation at the University of California, Berkeley.39

“The infrastructure here is really tapped,” Zuckerberg said Thursday. “Housing prices are way up. Traffic is bad.” He added that while Facebook is trying to do what it can to help with what he called the region’s policy challenges, “at this point we’re primarily growing outside of the Bay Area.” … The CEO said he prefers big hubs where Facebook engineering teams could be around one another, and that he doesn’t want to have a lot of small offices around the world, except for where sales teams need to be in the markets they’re serving.86

“58 of the 89 biggest — with headquarters of 100,000 square feet and above — tech and life science companies based in the Bay Area have leased 30.4 million square feet of office space in other U.S. cities since January 2010”86

Refugee migration

“An estimated 2.4 billion people–40% of the world’s population–live in a coastal region and will likely be impacted by rising sea levels as a result of climate change.”83

As of 2018, 70 million people were currently displaced by war, persecution and conflict. Of the total, 51 million were Internally Displaced People (IDPs), and 26 million were refugees (including 13 million refugee children). Most refugees live in towns and cities, not rural areas or refugee camps. Nearly 4 in every 5 refugees are in displacement situations that have lasted for at least five years.87

“Indonesia has already announced a $34 billion plan to move its sinking, flood-prone 30-million-person capital to higher ground”88

“There are billions of people living on coastlines that are going to be flooded. It’s going to be worse and worse and worse year by year and they are going to have to move eventually, and where are they going to move to? … we’re going to have to deal with that on a large scale” — Dr. Tom Goreau, president of the Global Coral Reef Alliance.88

“it has been estimated that it’s going to cost the USA alone around $400 billion over the next two decades in sea level rise damage control”88

Lost opportunities

“The San Francisco metro area [the counties of San Francisco, Alameda, Marin, Contra Costa, and San Mateo] is the third most valuable region in America based on the value of its residential real estate. The area’s total residential real estate value hit an astonishing $1.3 trillion and it’s outranked only by the Los Angeles and New York metro areas, with total residential real estate values of $2.2 trillion and $2.6 trillion, respectively.” … “San Francisco is one of three cities nationwide that can claim a market value higher than Apple Inc.’s $1 trillion.”33

“New city” greenfield developments

More than 120 new cities are currently being built in 40 nations around the world28, and 11,000 new buildings are built every day, meaning 4 million new buildings a year 89. (These developments are frequently called “new cities”, although often they are more like new suburbs or new satellite neighborhoods of existing cities, rather than brand new cities in their own right.)

“Neom is best described as a $500 billion … plan for a 10,000 square mile area”84

“New Cairo, … when completed, it could house as many as 5 million residents”84

“Forest City is a $100 billion new city development which will house 700,000 residents when completed. Forest city is a 5600-acre development.”84

New York land value

“At 305 square miles, New York City makes up only 0.008% of the total land area of the U.S., yet its $1.5tr of housing value is about 5% of the Nation-wide total. Only four states are worth more than New York City, one of which is New York State.”34

“Manhattan‘s housing alone is worth about $733bn, which would make it the 14th most valuable state in the country. Manhattan measures only about 20 square miles, 7.5% of New York City.”34

“What I found most striking of all was the value of some Manhattan neighborhoods. The Upper East Side, which occupies less than one square mile, has an astounding $96bn of housing value. That places it above Staten Island and the Bronx as well as above six states: New Hampshire, North Dakota, South Dakota, Vermont, Wyoming, and Alaska.”34

“The developable land in Manhattan—excluding parks, roads, and highways—was worth between $1.54 and $1.95 trillion, for an average of $1.74 trillion”37

Source material, chaper 5

Greenfield development vs. retrofitting

“when planned, built, and governed well, cities can be massive agents of positive change,” … “They can be catalysts for inclusion and powerhouses of equitable economic growth. They can help us protect the environment and limit climate change. That is why we need a new vision for urbanization.” — UN Secretary-General Ban Ki-moon 90

“Our biggest urban problems today—growing inequality, rampant gentrification, housing unaffordability, and increasing segregation—all have roots in the staggering cost of urban land.”37

“Three-quarters of the residential land in Los Angeles is restricted to single-family homes, according to UrbanFootprint, software that helps government and businesses understand cities and urban markets. In San Jose, the figure is 94%.” 39

Projects in existing cities can be staggeringly expensive.

“Retrofitting cities, where cities already exist, can be up to three times more expensive than planning for infrastructure in advance of settlement.” 38

“only about a quarter of New York City’s 472 subway stations are wheelchair accessible” … “subway officials … plan to add elevators at 70 stations in the next five years.” … “The Metropolitan Transportation Authority … estimates that accessibility fixes will cost about $78 million per station.” 15

Construction costs

“the price of construction for an apartment fully equipped with kitchen and bathrooms may cost several thousand US dollars per square meter (about US$2,500 per square meter in New York in 2013 for residential buildings three to seven stories tall).”16

“In the lowest-income countries, where construction is the cheapest, households would need to be able to afford at least US$6,000 for a studio of 12 square meters; US$6,000 is the global market commodity price for the basic construction materials of concrete and steel required to build 12 square meters.”16

“San Francisco has the world’s second-highest construction costs… The city’s average construction costs of $330 per square foot was second only to New York, according to a study last year by Turner and Townsend, a construction consultant. Apartments cost around $425,000 per unit to build.” 41

“New York and San Francisco topped the list of the most expensive construction markets, costing respectively an average of $354 and $330 per square foot to build. Seattle, which faces many of the same labor market and housing supply pressures as San Francisco, came in at $280 per square foot.”42

Funding for new city projects

“Cities generate roughly 80% of global GDP and are home to more than half of the world’s population today, a share that the United Nations projects will reach two-thirds by 2050,” the report said. About 40% of the population lives within 100 kilometers of a coast, and one in 10 people live in areas less than 10 meters above sea level, it said. 35

“The money being thrown at new cities is staggering. Saudi Arabia’s King Abdullah Economic City comes at a price tag of $100bn (£78bn), while the country’s Neom megalopolis is slated to cost five times that. Malaysia’s Forest City had its price initially pegged at $100bn, while Ordos Kangbashi cost a hulking $161bn. Adding up the costs of more than 120 new cities around the world means a mountain of investment that can be measured in the trillions of dollars.”28 — Wade Shepard, author and columnist

“An estimated $100 billion is being invested in new city projects across Africa; [the city of] Diamniadio alone will cost the Senegalese government an estimated $2 billion.”38

“Google pledged $1 billion to help create 15,000 homes in California.”91

“Apple commits $2.5 billion to address California’s housing crisis and homelessness issues”92

“South Sudan’s First Vice-President Taban Deng Gai said the government is working on a master plan for the proposed new capital city of Ramciel that will cost the nation 10 billion US dollars.”93

In 2019, U.S. Presidential candidate Andrew Yang called for $40 billion in subsidies, grants, and loans for people in coastal communities who want to either move inland or elevate their homes.94

Large private-sector projects

In the past, the truly large-scale new developments have all been done by governments, at least up to now. But until recently that was true for space exploration too. Times are changing.

The global banking and investment system is taking on larger private projects now, computers and the internet enable cheaper and faster R&D, recruiting, project management, etc. Global GDP gets bigger every year, and the world takes on new and bigger projects, both public and private.

Perhaps in the coming decades we’ll see increasingly large private-sector real-estate developments. Or, in the public sector, perhaps we’ll see some central planning efforts that are looking for big, cost-effective, high-impact solutions to giant housing shortages.

In recent decades we have begun to see the private sector take on very large scale projects, without government funding.

City Center, in Las Vegas, Nevada, is a good example

Banks, real estate developers, and the construction industry are now operating at a level where they can coordinate the successful delivery of very large projects.

In the 2020s and 2030s, is will not be crazy to propose a $20 billion privately funded construction project. The project just needs to pencil out well, be low risk, and meet the needs of customers.

Land value capture

There are established public-sector mechanisms for funding development projects, such as Tax Increment Financing (TIF).

“Portland, Oregon, currently dedicates about 40 percent of its TIF revenues to affordable housing. Over nine years, the program generated nearly a quarter of a billion dollars for affordable housing…”59

“The $6 billion Lincoln Yards development in Chicago … stands to receive $1.3 billion in TIF funding”59

“Value capture is a way to generate revenue by recouping a portion of the gains in the value of land that result from improvements of public transportation. … Common value capture mechanisms include:”45 ~ Leasing development rights or selling land. (e.g. Hong Kong) ~ Land Value Tax. ~ Tax Increment Financing (TIF). (e.g. New York)

“To conclude from the above literatures, value capture models are applicable to cities that have a good coordination of land use, city planning and economic development.”45

“Second, it should be able to acquire land at a favorable price, which will minimize the cost and maximize the profit from future land transition.”45

“despite this potential … value capture … doesn’t work in areas that are already developed. … undeveloped area provide the most room for growth.”44

“Hong Kong’s public transit development method, which is well known as a distinctive example of transit value capture. … Hong Kong is one of the few cities in the world where public transport makes a profit.”45

“In terms of land attribute, all land in Hong Kong is state property and the only land tenure is leasehold. The government of Hong Kong is responsible for land management, development, and its lease to private entities, based on China’s Basic Law passed in 1990. Private developers bid to lease land with a general 50 years term.”45

“The state leasehold system captures value from four major aspects: initial land auction, lease modification, lease renewal, and land rent collection. Among the four, initial land auction has been the major source of lease revenue, accounting for about 75 percent of government’s total land income (Hong, 1998).”45

“During the whole process, MTR is functioning as the master planner. It creates a development layout plan, monitors development quality, and manages the lease and sales of completed properties. It is a bridge between the government and developers. It sets clear rules to multiple stakeholders, making the partnership smooth and efficient.”45

“One reason that projects like Tsing Yi Station come into success is that the land use integration is evaluated at the master planning stage by MTR (Tang, Chiang, Baldwin & Yeung, 2004). This magnifies the interaction between railway and property development.”45

“Hong Kong’s strategy can be applied in cities where government owns the land.”45

“Thirdly, the planning of public transportation requires multiple levels of government and agencies to work together. It is important to form a good collaboration between the different development stages, including land acquisition, planning, construction, operation, and property management. In Hong Kong, for example, MTR as a single agency is responsible for the whole development cycle. The process is more efficient, because it saves additional administrative cost, and there is only one principle from beginning to end. For New York, however, as MTA is only responsible for railway construction and operation, and it has no right of land use, the capability of capturing land value is to some extent undermined.”45

“Bartholomew and Ewing’s (2010) study indicates transit accessibility, walkability, and environment quality can be capitalized into real estate prices. The existence of high walkability and mixed land use types are likely to increase land values independent of transit accessibility.”45

“Other factors related to the value generated from public transportation include the service quality, the extent of network, and the ticket price. Andersson (2010) conducted a research about the high speed rail in Taiwan, and finds out that it has little impact on land values due to the high ticket price (A monthly ticket can take up to 70% of the median monthly wage in Taiwan). It is difficult to capitalize expensive services into land values.”45

“Hong Kong is a small island city with an area of 1104 square kilometers. To date, the city has a population of 7.1 million, and is projected to reach 8.6 million by 2026 (HK Census and Statistics Department, 2014).”45

“Zoning regulations allow special FARs in key station areas to attract private investments and comprehensive development.”45

“Corner lots are significantly more valuable than mid-block lots, according to the study, and lots in close proximity to Broadway, which runs the length of the island, also have higher values.”37

Source material, additional

“More recent data, however, reveal substantial urban‐rural fertility gaps (i.e. of one child or more per woman) that tend to be wider at more advanced stages of the fertility transition” 49

“In the full sample of countries, rural fertility is almost 20 percent higher than the urban level on average in the pre‐transitional cohorts. … The ratio increases sharply in the first 20 transition cohorts to 40 percent, stabilizing at this level in the subsequent 10 cohorts. After 30 cohort years have elapsed since the transition onset, the average rural‐urban ratio has dropped monotonically down to 1.23 (in the 55th transition cohort).” 49

“Double the size of a city and on average you’ll find twice as many businesses. The proportionality constant is 21.6, meaning that there is approximately one establishment for about every 22 people in a city, regardless of the city size. Or to put it slightly differently, on average a new workplace is created each time the population of a city increases by just 22 people. … on average, there are only about 8 employees for every establishment, again regardless of the size of city.”7 — Geoffrey West

Congestion pricing

In their 2009 book, aptly title Mobility First, Sam Staley and Adrian Moore describe in detail the cross-disciplinary reforms in road and urban transport design and in road pricing, among other things, that would be required to maintain mobility in cities in the twenty-first century.16

The rent charged should vary with the time of day, the location, the area, and the length of time the road is used. The rent charged for roads should be similar to the fares charged by airlines to passengers or the room rates charged by hotels, except that the rate would not be for a fixed 24 hours but for the number of minutes the roads are actually used.16

Freight

“And New York City, where more than 1.5 million packages are delivered daily…” 3

In New York City, “Delivery trucks operated by UPS and FedEx double-park on streets and block bus and bike lanes. They racked up more than 471,000 parking violations last year, a 34 percent increase from 2013.” 3

“The main entryway for packages into New York City, leading to the George Washington Bridge from New Jersey, has become the most congested interchange in the country. Trucks heading toward the bridge travel at 23 miles per hour, down from 30 m.p.h. five years ago.” 3

“The average number of daily deliveries to households in New York City tripled to more than 1.1 million shipments from 2009 to 2017, the latest year for which data was available, according to the Rensselaer Polytechnic Institute Center of Excellence for Sustainable Urban Freight Systems. … Households now receive more shipments than businesses.” 3

“And it could be just the beginning. Just 10 percent of all retail transactions in the United States during the first quarter of 2019 were made online, up from 4 percent a decade ago, according to the Census Bureau.” 3

“About 15 percent of New York City households receive a package every day, according to the Sustainable Urban Freight Systems center at Rensselaer.” 3

Notes

TODO: include on this web page some animated images of traffic simulations for the Impossible City design, maybe somewhat like the SUMO simulation output images on this page: sidewalk-talk

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