Ambient Traffic Jam

Ambient Traffic Jam drops a living, cosmetic traffic jam into any scene. Cars pack bumper-to-bumper in lanes and follow the car ahead — accelerating to close a gap, braking to a safe stop — while flipping between random go/stop phases, so pauses ripple backward as real stop-and-go waves. A camera-anchored window keeps the belt full: cars that fall off the rear edge are recycled to the front, so the jam never "ends" and the live car count stays bounded no matter how far the player travels.

It's built to be pure background dressing: no colliders during normal play (zero physics cost), and every bit of randomness comes from a private RNG, so it never disturbs a seeded/deterministic gameplay RNG. Per-car body colour is applied with shared material variants (not per-object property blocks), so every car stays SRP-batched — variety with no extra draw calls.

Fully data-driven and customisable: add as many lanes as you like, set each lane's position, side and crawl speed, drop in your own car/bus/truck prefabs, tune jam density, stop timing, colour palette and engine-audio, and optionally wake impact colliders around a target (e.g. on player death) via a single call. Great for endless runners, city drivers, top-down and isometric games, or any scene that needs believable idle traffic.

Includes a ready-to-use URP demo scene with original low-poly vehicles and engine-loop audio, plus a full PDF manual. Requires Unity 6000.3+ and the Universal Render Pipeline.