Streets and corridors

The one-minute explanation

Roads cost no development capacity (Part 1), so the limit on your network is not entitlement — it is whether the geometry works and whether the streets actually reach the buildings. Road access is one of the components of your transport score, measured at 80 m from every building zone.

Three ideas do most of the work in this tool:

The five classes

The speeds are defaults, not fixtures — every one can be edited per road afterwards. What the class really gives you is a coherent starting section, so a “branch” arrives already knowing that a community street has two directions and pavements.

The cross-section is yours

Once placed, the section card exposes the road’s whole geometry:

The card totals the resulting width live, and marks the road as modified once its section drifts from its class — which is how you tell a customised avenue from a default one at a glance.

Two habits pay off. The eyedropper copies a section from an existing road, so a consistent street hierarchy does not have to be rebuilt by hand. And favourites save a section you like as a preset, which can then be applied to many selected roads at once.

Ground, elevated or tunnel

How a road is carried is a separate choice from what class it is, and it persists when you switch class. That orthogonality is deliberate: an elevated secondary and an elevated expressway are the same construction decision applied to two different streets, and changing your mind about the class should not silently drop the viaduct.

Corridors: one road, several carriageways

A road with separated carriageways is not several roads that happen to be parallel. It is one corridor, carrying one name, and it can be edited as a whole — change the corridor and its carriageways are rebuilt from the centreline together.

This matters because the alternative is the trap: eight parallel fragments that drift out of alignment, each needing the same edit, and none of which the city recognises as the same street. When you do want a carriageway to go its own way, there is an explicit operation to break it out into an independent road.

Junctions state an intent

Where a new road meets an existing one, the city asks what you meant rather than guessing from geometry. The intents read as plain sentences — this exit leaves the highway here, this ramp merges into it, this one is merely snapped to the kerb and forms no connection at all.

That last case is the one to watch: a road can look connected and carry nothing, because touching is not joining.

When a connection does fail, the city names the cause and offers the remedy rather than reporting a generic error — there are eight distinct causes, each with its own explanation and a reconnect action. Working through the named cause is almost always faster than redrawing the road.

Drafts are first-class

A road you draw but do not confirm stays as a draft — dashed and yellow — and survives saving and reloading. You can plan a whole district speculatively, leave, come back and either confirm it, keep it as a draft, or discard it.

This is what makes the layer usable as a planning tool rather than a commitment device: nothing is built until you say so, and unbuilt intentions are not lost.

What you can do to a road afterwards

Beyond editing the section, a selected road offers a set of operations worth knowing by name:

• Extend — continue the road, inheriting its section. It keeps the name only when the new stretch carries on in roughly the same direction; a stretch that turns sharply away is treated as a new road and named on its own.
• Branch — start a new road from it.
• Openings — add or remove crossings through a median, which is what lets traffic turn where you intend rather than only at the ends.
• Local widening — over a stretch of at least 20 m, add a bus bay or a turning pocket without changing the whole road; a single action clears them all again.
• Duplicate — a parallel road with the same section.
• Elevated alongside — add a viaduct following the existing road.
• Independent — split a carriageway out of its corridor.
• Eyedropper — take this road’s section for the next one.
• Demolish — the road, or the whole corridor, or just dissolve the corridor grouping while keeping the carriageways.

Demolition checks your bus routes

Bus lines are routed over your streets rather than drawn on them, so demolishing a road can silently strand one. The city guards against this — but deliberately only against real damage.

It compares the network before and after the demolition, and blocks only two cases: a route with a stop or via point sitting on that road, and a route whose leg can be routed now and cannot afterwards. A route that merely passes along the road is not blocked, because a parallel street may well carry it instead — and blocking that case would forbid a legitimate edit like removing a redundant road and letting the line reroute itself.

When it does block, it names the routes so you know exactly which line to deal with first.

Practical habits

1. Set the class, then the construction method, then the section. In that order the tool stops fighting you, because the construction choice survives class changes.
2. Build corridors as corridors. Resist drawing two parallel roads by hand for something that is one avenue; the whole-corridor edit is worth it the first time you change your mind about lane count.
3. Place openings deliberately. A long median with no crossings is a wall, and it will show up as unreachable pairs in the demand board rather than as an obvious error.
4. Draft first on anything large. Drafts persist, so there is no cost to sketching a district and confirming it a session later.
5. Sweep for broken connections before judging your traffic. A road that touches without joining looks perfect and carries nothing.

Common misconceptions

“I should build cheap streets and upgrade later”

There is nothing to save. Roads consume no capacity and no money, so the only reasons to choose a smaller class are geometry, appearance and the traffic you expect.

“The roads are touching, so they are connected”

Snapping to a kerb forms no connection. The intent is explicit, and the city will tell you which of the eight causes applies when it fails.

“Two parallel roads are the same as a divided avenue”

Only a corridor is one object. Two hand-drawn carriageways must be edited twice, and can drift apart.

“Demolishing a road will break my bus routes”

Only if it genuinely would. The guard compares routability before and after, so removing a redundant street and letting the line reroute is allowed — what is blocked is a stop sitting on the road, or a leg that becomes unroutable.

Continue the collection

Next: the networks that run above and below these streets — city railways, four transit modes, and the bus lines that route themselves over what you just built.