Ambient Audio
The TrafficTool runs a Dynamic Ambient Audio system that turns a silent track into a living environment. On top of the expected sounds — engine noise attached to each traffic car and sirens on police units — the system continuously evaluates where you are in the world and layers additional environment sounds on top, distance-based, with a set of context rules that decide which loops play and how loud. The result is a soundscape that shifts as you drive: the forest sounds different from the beach, the open meadow sounds different from a dense downtown road, and the transition between them happens without you touching anything.
Where to find it
The master ambience toggle is in the Main tab’s Quick Settings. Per-layer volume sliders live under Advanced Traffic Settings → Sound when Show Advanced Settings is on.
How the Dynamic Ambient Audio system decides what to play
The system reads your position in the world and looks for features around you: traffic lanes, trees, open grass, water bodies, sand, and so on. Each kind of feature has its own ambient layer, and the system mixes those layers together based on how close you are and how much of each feature is present. As you drive, the mix shifts: one layer fades as you leave it, another fades in as you arrive. Nothing about it is manual — you do not place zones yourself, you do not pick which loop is active, and the system does not wait for a scripted trigger.
Below are the rules that produce the current soundscape. You can hear each of them by driving into contexts that satisfy them.
Road ambience near traffic lanes
Being near authored traffic lanes activates a street ambience layer — the low-level sound of cars driving past, tyre hum on tarmac, general road atmosphere. Volume scales with how many lanes are near you and how close you are to them: a single lane on the other side of a field produces a soft hum; a six-lane boulevard right next to you produces a dense, busy sound. This is separate from any individual traffic car’s engine audio — it is the background the cars sit inside.
Forest and birdsong near trees
When there are trees around you, the system adds a forest layer — leaves rustling, birdsong, the characteristic hush of a wooded area. Drive out of the forest and the layer fades; drive back in and it returns.
Wind on open meadows with little traffic
Standing on grass away from traffic lanes produces a wind layer — a light breeze across open ground, without engine sound and without road hum. This is what gives a rural pull-over a distinctly different sound from a pull-over on a city roundabout even when both are technically quiet.
Harbour ambience on highways near water
When you are on a highway stretch that runs near water, the system adds harbour ambience — rigging, distant foghorns, dockside activity. The combination of “fast road” and “water nearby” is the trigger, so a seaside highway sounds unmistakably different from a seaside dirt track.
Waves and beach at the water’s edge
Standing next to water with sand around you brings in waves and beach ambience. This is a more specific rule than just “water nearby” — the sand is what tips it from a generic shoreline into a recognisable beach.
Other context rules exist for niche situations. If you hear a specific layer you cannot place, it is the system reacting to a combination of features in the world around you. None of this is randomised: drive back to the same spot under the same conditions and you will get the same mix.
Right-click to reset
Every volume slider reverts to the current preset’s default value when right-clicked. Use this if you have been experimenting and want a neutral baseline.
Traffic and police sounds
Separately from the Dynamic Ambient system, traffic cars carry their own engine audio and police units play siren sounds when they are in pursuit. Both have dedicated volume sliders (Traffic Sound Volume, Police Siren Volume) alongside the ambient slider. These are not part of the dynamic ambient system — they are per-car audio sources — but they share the mixing panel for convenience.
Troubleshooting
- No ambience at all
- Check the master Enable Ambient Sounds toggle, and confirm Ambient Sound Volume is not at 0 (setting it to 0 also disables the master toggle).
- I hear the wrong ambience
- The system reads the features around you in-world. If it plays forest when you expect open road, it is because the track places trees close to where you stand — check the actual geometry around the car.
- Ambience cuts in and out
- You are at the edge of two contexts. Driving slightly into one or the other stabilises the mix.
- Volumes reset after clicking a preset
- Presets reapply default sound levels. Tune after clicking a preset, not before.