Trafficity Traffic Light Phases: How to Tune Signals for Better Flow

A jammed junction in a city builder usually means widening the road or bulldozing a block. Trafficity offers a cheaper lever first: Trafficity traffic light phases you can reassign, retime, and expand by hand. This guide walks through how Trafficity traffic light phases work in the game's pre-release build, why a signal is often the right first upgrade, and how to tune one without starving the crossing it is supposed to fix.

Why Signals Matter More in Trafficity Than in Other City Builders

Trafficity inverts the usual city-builder priority. The zoning, building placement, and growth loop is deliberately relaxed, while the road network and vehicle simulation carry the complexity — and the roads are gridless, so you can draw free-form curves, one-way loops, and custom interchanges instead of snapping everything to a square.

That matters for signals because you are not decorating a fixed grid with stoplights. You are deciding, junction by junction, how conflicting movements share space on roads you invented.

Two structural details shape every decision:

• Buildings appear to be free to place; road infrastructure is what drains the budget. In the build shown, the objective loop asked the player to place specific buildings to advance, and only the roads came with a cost.
• The economy is mode-dependent. The preview showed a sandbox-style "chill" option with unlimited money, a standard experience, and an expert mode with stricter requirements and less funding.

The source for everything below is a single hands-on preview by the creator Exact Chaos, recorded on a pre-release key from the studio the video names as OnRamp Games. Treat build-specific details as a snapshot rather than a permanent feature list, and check Trafficity's Steam store page for the live feature set and release status.

Where Traffic Light Phases Come From: Junction Upgrades

Signals are not a road type you paint down. They arrive as a junction upgrade, offered when a crossing starts to back up. In the preview, the first genuinely congested intersection prompted an upgrade menu with three directions to go:

The preview used all three across the session, and the honest takeaway is that none of them is universally correct. A roundabout helped one junction distribute flow; extra lanes solved a pure capacity problem at another; and the signal was reserved for the messy, multi-directional crossing where queuing kept reforming.

Player experience from the same preview: adding lanes first, then layering a signal on top, produced the cleanest result — capacity, then control.

Step by Step: Setting Up Trafficity Traffic Light Phases

Once a signal exists, the interesting work begins. Here is the workflow the preview demonstrates.

1. Place the signal. Pick the traffic light option at the congested junction. It arrives with a default configuration — in the preview, two phases running out of the box.
2. Assign lane movements per phase. The signal editor lets you drag lane connections so you decide which approach lanes discharge in which phase. If a movement is already handled by a slip lane, you can remove it from the signal entirely.
3. Set relative phase length. You can make one phase longer than the other, which is the practical equivalent of giving the dominant movement more green time.
4. Build custom phases if the default split is wrong. Beyond the two-phase default, the editor supports creating your own phase sets.
5. Recheck the flow figure. Traffic flow is a tracked percentage, and the early objective in the standard mode asked for 95% flow alongside 95% building satisfaction.

That lane-level control is the heart of Trafficity traffic light phases. A signal is not a blanket "stop here" object — it is a small scheduling problem, and the editor gives you both the movements and the clock.

One caveat worth repeating: the preview's creator found the road tools occasionally finicky, particularly when rebuilding junctions, so expect to delete and redraw a connection rather than get it perfect first time.

Read the Overlays Before You Retime a Signal

Retiming a signal to fix a number you do not understand is how cities stall. Trafficity ships overlays that tell you which system is actually failing:

• Traffic flow — the headline percentage, tracked against your objectives.
• Building satisfaction — a composite of worker access, goods delivery, and customer access.
• Access to workers, nearby workplaces, nearby commercial, and input resources — the logistics view.
• Air pollution and road noise — side effects that follow congestion and heavy roads.
• Map-wide access — the tooltip in the preview noted that residents spend roughly a third of their time visiting locations across the whole road network, so point-to-point travel time matters, not just the junction in front of you.

If satisfaction is falling because homes lack nearby commercial, a signal will not help. If noise is spiking along an arterial, the fix is hierarchy and routing, not green time.

Trafficity Traffic Light Phases: Mistakes the Preview Exposes

Watching a transport planner play is a fast education in what not to do.

• Skipping road hierarchy. The preview builds around a primary arterial with collector and local roads hanging off it. Nothing connects directly to the arterial, which keeps the main corridor clean.
• Fusing everything into one grid. The creator noticed that because the simulation tests routes with many agents at once, a fully connected network sends everyone down the same attractive path. Deliberate disconnection is a tool.
• Crowding junctions together. Closely spaced crossings produced vehicles blocking each other. Spacing them out, using keep-clear markings, and adding slip lanes all reduced the damage.
• Expecting a signal to add capacity. A signal allocates conflict; it does not create throughput. The preview paired the signal with extra approach lanes and a slip lane, and only then did flow recover.

The broader lesson: Trafficity traffic light phases are the scalpel, not the hammer. Use them where movements genuinely conflict, and solve raw capacity with asphalt.

FAQ

Do Trafficity traffic light phases always beat a roundabout? No. The preview treated them as alternatives in the same upgrade menu. A roundabout handled moderate circulating demand well; the signal was chosen where turning and through movements kept colliding at a compact junction.

Can I change how long each phase lasts? Yes. The signal editor allows one phase to be set longer than the other, and it supports creating custom phase sets rather than forcing you into the default two-phase split.

Why did traffic get worse after I added a signal? Usually because the signal removed capacity the junction was relying on, or because route reassignment pushed more vehicles toward the new configuration. Pair signals with approach lanes, slip lanes, or better spacing before judging them.

Is this guide based on the finished game? No. Every detail here comes from a pre-release preview captured on 2026-11-09, so tuning values, upgrade options, and Trafficity traffic light phases themselves may change before or after launch. Verify the live build on Steam.