# road

> Talos next · Since 0.6

A road: a ribbon with kerbs, barriers and trigger gates built from a `.road.json` file, with trimesh colliders and a centreline scripts can read (`ctx.world.road`).

Works in a scene with no terrain. The entity's transform places the road; its parts are entities placed at it (not parented) `<id>-surface`, `<id>-barrier` and `<id>-gate-<n>`.

Use it in a scene entity's `components` list as `{ "type": "road", … }`. The contract writes the fields flat and refuses unknown keys.

## Fields

| Field | Type | Required | Default | Allowed values | Description |
|---|---|---|---|---|---|
| `source` | `string` | yes |  |  | Project-relative .road.json file. |
| `material` | `PhysicsMaterial` | no |  |  | Physics material of the road surface collider (grip). Default: the engine's default. |
| `barrierMaterial` | `PhysicsMaterial` | no |  |  | Physics material of the barrier colliders (bounce). Default: the engine's default. |

## Rules that can refuse it

- `road-material-unknown`
- `road-source-invalid`
- `road-source-missing`
- `road.at`
- `terrain/road-buried`