What Frostpunk Teaches About Radial City Plans

Every few years someone sends me a concept for a new town laid out as a perfect circle, streets radiating from a central square like spokes on a wheel. The drawings are always beautiful. The plans almost never get built as drawn, and the ones that do tend to spend the next century quietly fixing themselves. Radial plans look like order on paper and behave like a puzzle on the ground.

The best demonstration of why I have found in recent years is not a planning textbook. It is Frostpunk, the 2018 city builder from 11 bit studios, where you lay out a settlement in concentric rings around a giant coal-fired generator in a frozen crater. The game makes the radial plan feel inevitable, and in doing so it shows exactly what conditions a radial plan needs before it makes sense anywhere else.

How Frostpunk forces a circle

In Frostpunk the world is lethally cold, and the generator at the centre of your crater is the only reliable source of heat. Its warmth spreads in rings, and anything outside the heated zone freezes. Roads extend outward from the generator along fixed radial lines and wrap around it in circular rings, and buildings snap into the spaces between them.

The result is that every decision about where to place a building is really a decision about distance from the centre. Houses and medical posts go close to the heat. Coal mines, sawmills and hunters' huts go further out, where workers suffer but can still reach them. Heat is a radial resource, so the plan follows it. It is about the clearest example I know of form following a single dominant constraint.

Players often describe their early cities as "rings of tents around a furnace." That is not far from how some real settlements have grown around a well, a church, a market or a fortress. The question is what happens when that single constraint fades.

What real radial towns ran into

Two European examples are worth knowing in detail, because they were planned as radial schemes from the start rather than growing that way.

Palmanova, in north-eastern Italy, was founded by the Venetian Republic in 1593 as a fortress town, laid out as a nine-pointed star with streets radiating from a hexagonal central square. Its geometry was driven by artillery: the star shape let defenders cover every approach. The problem came when Venice tried to fill it with people. Few wanted to move to a military town with awkward wedge-shaped plots, and by the 1620s the authorities were offering pardons to convicts who agreed to settle there. The plan solved a defensive problem very well and a living problem very badly.

Karlsruhe, in south-west Germany, was founded in 1715 around a palace tower, with 32 streets fanning out from it, a design inspired by the radiating rays of the sun. Only the southern section of the fan was built up as a town; the northern part stayed as palace gardens and forest. The city grew and thrived, but much of its later expansion follows an ordinary grid, because the fan pattern does not extend gracefully once you are far from the centre.

The same three issues show up in both towns, and they are exactly the issues Frostpunk players hit when their city outgrows its first rings.

Plots become wedges. Rectangular buildings fit poorly into the triangular spaces between spokes. You either waste the corners or design odd-shaped buildings, which cost more.

The centre jams. Every journey from one side to the other passes through or near the middle. In Frostpunk this shows up as workers crowding the inner roads. In real towns it shows up as traffic converging on the central square.

The outer rings stretch. Each new ring is longer than the last, so the amount of road per building rises as the city grows. The spokes also drift further apart, leaving big gaps between them.

The advice I would challenge: radial plans are "more efficient"

A claim you will sometimes see in planning discussions, and frequently in game communities, is that radial layouts are inherently efficient because every point is a short straight line from the centre. That is true only if the centre is the only place anyone needs to go.

In Frostpunk it is close to true. Heat, the main workplaces and the gathering places are all near the generator. In a real town, people travel between dozens of places that are not the centre: schools, clinics, shops, friends' houses, the station. For most of those trips, a grid with a few diagonals performs better than a pure radial, because it offers many roughly equal routes rather than funnelling everyone through one point. Studies of street networks generally find that well-connected grids spread traffic more evenly, though the details depend heavily on block size and how the arterial roads are placed.

So I would rephrase the claim. A radial plan is efficient when one central resource dominates daily life. Remove that, and its advantages shrink while its costs stay.

Where the Frostpunk logic still applies today

The interesting part is that heat, Frostpunk's central resource, has quietly come back into real planning. District heating, where one plant pipes hot water to many buildings, works best when buildings are close together and close to the source. Copenhagen's district heating network reaches nearly every building in the city, and much of the reason it works economically is density. Piping heat a long way to scattered buildings loses energy and money in the same way Frostpunk's outer rings lose warmth.

This does not mean new neighbourhoods should be circular. It means that when a shared energy source is part of the brief, its location should shape the layout from the first sketch, with the densest, most heat-hungry buildings placed closest to it. Our piece on how heat pumps are changing the way we heat buildings covers the building-scale side of the same question, and why orientation decides a home's comfort handles the sun's part.

For a wider look at what city builders get right about planning, see how city-building games teach the logic of good architecture, and our notes on settlement planning and walkable neighbourhoods.

One exercise for this week

Pull up a satellite view of the town or neighbourhood you live in and find the single place most daily trips actually lead to. It might be a station, a supermarket or a school. Then trace the main roads and ask whether they point toward that place or past it. If the layout and the destination disagree, you have found the spot where your town, like a Frostpunk city that outgrew its generator, is quietly working against its own plan.