Traffic Architect Interchange Placement & Turn Rules

Start from the placement case you actually have

Place it, inspect it, then resume

1. Pause before making the build so you retain the documented immediate undo option.
2. Choose Interchange and the road class you want its generated roads to use.
3. Position it using the relevant case above. On open ground, position the center, then orient each road using the preview and available snaps.
4. Inspect the whole footprint, connections and neighboring roads before completing the placement.
5. After placement, inspect the ramps and permitted turns where they meet the main road.
6. If the placement is wrong, use one Ctrl+Z while paused. The 1.0.7 notes say this takes the interchange back and restores the crossing as it was.

That is a paused-build undo rule, not an unlimited demolition refund after the city has continued running. The refund tag beside the balance shows what is currently available.

The interchange may also place no-turn signs

Since 1.0.8, a new interchange on a main road without a median places no-turn signs where its ramps meet that road. The purpose stated in the patch is to keep cars using the ramps instead of cutting across traffic; sign cost is included in the interchange price.

Inspect that result rather than adding another physical turn lane in an attempt to ban the movement. For manual changes, use the junction’s turn controls. Reset junction also removes its turn bans in 1.0.8, so record intentional restrictions before resetting it.

If a road or ramp refuses the placement

Use the actual current preview and error. Earlier fixes and the newly released full version change the context:

• The early Demo notes say a refused interchange shows its full red footprint, helping you see the space it needs.
• 1.0.7 improves cloverleaf fitting and handles roads drawn in pieces. It does not prove every crossing can fit every interchange.
• Full 1.1.0 limits the second road to allowed angles and fixes a ramp being built on top of a road beside it. Those are developer-announced full-version fixes; a Demo update to the same build is unverified.

If it still refuses, keep the selected class, shape, version and a screenshot of the complete preview. A bend, adjacent road or different-width merge is a specific geometry case, not evidence that you must erase the whole district.

Placement is only one part of a working junction

An accepted footprint does not guarantee better traffic. Check that required entry and exit routes still exist, then judge the traffic after the change. This guide covers placing and reversing the tool’s result; it does not claim an optimal interchange for every city, a solution to every challenge or a coordinated signal system.

The placement task is complete when the intended road class and directions are connected, the generated ramp junctions have the restrictions you want, and you have kept or undone the build before leaving its paused undo window.