City · Part 1 · About 10 minutes
Land, allowance and no construction fund
The City Map runs on different rules from the nation above it. Nothing here is paid for out of the Transport Fund, because there is no construction fund at all. What limits you instead is an allowance — how much land your population reaches across, and how much building your development has earned the right to.
There is no construction fund
On the national map, the Transport Fund pays for everything. A road is quoted against it before you build, maintained from it every month afterwards, and depreciated on the balance sheet for decades. Every decision up there is a decision about that account.
The City Map has no equivalent. There is no construction fund behind it, and the Transport Fund does not reach into it: a boulevard, a metro line, a district of towers, a reclaimed island — none of them is quoted, none is charged, none appears in the Income Statement, and none changes a single figure in your national accounts. You can redraw a city ten times over and the nation will not notice, because nothing was ever billed.
This is the single most important thing to carry into the layer. Players arriving from the transport game look for a quote against the Transport Fund, find none, and then meet a wall they did not expect. The wall is the allowance, and it is not made of money.
The land you may build on
The buildable area is drawn from population, not from anything you do in the city.
Each settlement in the metro projects a circle sized by its own population. The metro then adds one more circle at its centre, sized by the combined population of all its members. The buildable area is the union of all of them — so a conurbation reaches further than its towns would separately, and the area grows on its own as the population does.
Member circles plus one metro-wide circle at the centre. Nothing you build changes it.
Only dry land inside that reach can be built on. A coastal metro may have a wide reach and much less ground.
Two consequences worth planning around. A metro on a peninsula or split by water has far less usable land than its population circle suggests — and the HUD reports the real figure, land area rather than reach. And the reach expands while you are inside the city: the game recomputes metro membership every quarter, so a growing city quietly gains room at its edges.
Anything you try to place outside the reach is refused, including a road whose envelope — its full width with sidewalks and frontage roads — crosses the boundary even when its centreline does not.
The allowance you may build with
Land is permission to occupy space. Development capacity is permission to build, and it is metered separately for each kind of thing you might build.
For every member settlement and every category, the cap is:
Each member is measured with its own population and its own development, then the results are added. This matters: a small, highly developed town cannot inflate the allowance of a large, undeveloped neighbour it happens to share a metro with.
What development is worth
The development factor runs from 60% at level 0, through 100% at level 50, to 140% at level 100. So the allowance never starts at zero — an undeveloped city can still build — but the difference between a backward and an advanced settlement is a bit more than double.
Crucially, each category reads its own development fields rather than the overall score. Residential capacity is driven by administration, healthcare and education; industrial by industry and logistics; commercial by commerce. Raising the field that matters lifts exactly one cap.
What each category is worth per person
The per-person allowance is where the city’s intended shape is encoded. A few of the sixteen, in square metres per resident:
| Category | Per person | Driven by |
|---|---|---|
| Residential | 30 m² | Administration, healthcare, education |
| Parks and green space | 10 m² | Administration |
| Civic infrastructure | 6 m² | Administration, logistics |
| Industry | 4 m² | Industry, logistics |
| Offices | 2 m² | Commerce, administration, education |
| Education · Sport · Parking | 2 m² each | Their own fields |
| Commerce | 1.5 m² | Commerce |
| Plazas | 1.5 m² | Tourism, administration |
| Medical | 1.2 m² | Healthcare |
| Public services | 1 m² | Administration |
| Passenger terminals | 0.8 m² | Logistics, commerce, tourism |
| Stations · Airside | 0.5 m² each | Logistics, commerce, tourism |
| Heritage and religion | 0.3 m² | Tourism, education |
Read the ratios rather than the absolute numbers. Thirty square metres of housing per resident against one and a half of shops is what makes a plausible city: the residential allowance is enormous because people need somewhere to live, and the commercial allowance is small because a shop serves hundreds of them. Trying to build a city of towers with no housing runs out of allowance almost immediately.
Lines are free; stops are not
One asymmetry surprises everybody. Roads, railways, transit lines and bus routes consume no capacity at all — you may build as much network as you can draw. But a station, a passenger terminal or an airside area is a zone, and it draws on the transport allowance like any other category.
So the constraint on your network is geometry and usefulness, never entitlement. The constraint on the buildings that serve it is entitlement like everything else.
How your usage is measured
Two kinds of thing are counted two different ways:
- Buildings are counted as floor area: the zone’s footprint multiplied by its floor count. Adding storeys spends allowance exactly as spreading out does. A courtyard cut into a building is excluded.
- Land uses — parks, plazas, water — are counted as ground area, and overlapping shapes count once. You cannot inflate a park by stacking copies of it.
Mixed-use zones are split across the uses they declare, in the proportions you set.
When the allowance is full
The refusal is precise about the remedy:
It fires when you place a zone, when you add floors, and when you change a mixed-use split — anywhere your usage would rise.
What it does not do is invalidate what you already built. The rule is deliberately forgiving: a city already over its cap may stay over it, and may always reduce. Only a change that increases usage and ends above the cap is refused. So a settlement whose development falls — after congestion, or a decline — never has its city condemned. It simply cannot grow further until the development recovers.
That gives you two ways out of a full category, and they are genuinely different plays: raise the driving development field on the national map, or demolish something you no longer want. Both are covered by the instruments in Reading your city, which shows every category’s bar.
The city cannot touch the nation
The city reads the nation constantly — population, development, terrain, your macro roads and railways — and can change none of it. This is enforced in the code itself, not merely intended: the national state arrives in a form the city layer is incapable of writing to.
So no amount of city design will move a GDP figure, alter a demand matrix, reroute a national line or spend a currency unit. The city is a plan drawn on top of a country.
The one thing that goes back
Exactly one number crosses in the other direction. When you leave a city, its completeness score is recorded: how much of its core allowance is actually built out, weighted with how well its streets and transit serve it.
That score becomes a small multiplier on the development growth of the metro’s member settlements — starting at up to +5%, and rising to +10% and +15% as you reach the Million City and Metropolis milestones. It is anchored to the population at the moment you left, so the bonus decays as the city outgrows its snapshot; returning, extending the city and leaving again refreshes it.
This is the loop that makes the layer worth playing: development grants allowance, allowance lets you build, building well accelerates development. The composite and how to raise it are covered in Reading your city.
What is saved
Each city is stored per metro and per save game, alongside your national save rather than inside it, and it holds everything you drew — streets, corridors, railways, transit and bus lines, zones, markers, terrain edits, reclamation, named entities and their logos. Unbuilt drafts persist too, returning as dashed outlines.
A save-state dot reports clean, unsaved, saving or failed. One deliberate behaviour is worth knowing: if a city’s data cannot be read, the game opens it read-only and refuses to write, rather than risk overwriting a good save with an empty one.
Common misconceptions
“I should budget for this district”
There is nothing to budget. City construction has no quote, no maintenance and no depreciation, and never draws on the Transport Fund. Budget pressure lives entirely on the national map.
“I need a higher development score”
Not the score — the field. Each category reads its own development fields, so raising healthcare lifts medical capacity and leaves industry exactly where it was.
“My development dropped, so my city is illegal”
Existing development is grandfathered. You keep what you built and may tidy or shrink it; you simply cannot add to a category that is over its cap.
“My road network is using up my allowance”
Lines cost no capacity. Only zones do — including the stations and terminals that serve those lines.
Continue the collection
Next: the instruments that show your allowance, your completeness and the traffic your plan produces.