How to Run Modded Assetto Corsa Traffic Servers (2025 Guide)

Assetto Corsa’s mod scene makes open-world cruise and traffic servers the go-to experience for car meets, touge runs, and role-play communities. This guide walks you through hardware sizing, mod packaging, and the exact server settings needed for stable modded traffic lobbies.

What you’ll learn:

• Required tools (Custom Shaders Patch, Sol, Content Manager, traffic packs)
• Recommended hardware and bandwidth by player count
• How to assemble and sync a traffic-ready mod bundle
• Key server_cfg.ini, entry_list.ini, and CSP traffic settings
• Performance tuning, admin workflows, and launch checklist

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Table of Contents

1. What Are Assetto Corsa Traffic Servers?
2. Core Mods and Tools
3. Hardware and Network Requirements
4. Hosting Options
5. Build Your Mod Pack
6. Server Installation & Configuration
7. Traffic Logic & AI Lanes
8. Syncing Mods with Players
9. Performance & Stability Tuning
10. Admin Tools & Monitoring
11. Common Issues & Fixes
12. Launch Checklist
13. Host with Mamba Host

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What Are Assetto Corsa Traffic Servers?

Traffic servers swap competitive racing for open-world immersion. They combine:

• Free-roam maps (Shutoko Revival Project, L.A. Canyons, Pacific Coast, Akina)
• CSP traffic routes with AI lane files and spawn logic
• Mixed vehicle classes (traffic, police, player cars) with dynamic weather and day/night cycles
• Channels for role-play, cruises, drifting, and photography

A typical lobby runs 24-64 concurrent drivers, spawns AI commuter traffic, and enforces consistent mod versions so every client sees the same world.

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Core Mods and Tools

• Custom Shaders Patch (CSP): 0.1.80+ for traffic planner, extended physics, and rain. Enable “New AI behavior” and “Traffic planner support.”
• Sol 2.3+ or Pure: Adds weather, dynamic lighting, and time sync.
• Content Manager (CM): Third-party launcher with Server Manager, mod auto-sync, and CSP tweaks.
• Traffic Pack: traffic.json, ai_lanes.ini, traffic car models, and spawn groups. Popular packs ship with Shutoko or L.A. Canyons downloads.
• Server binaries: acServer (Windows) or Linux binary from SteamCMD (steamcmd +login anonymous +app_update 302550 validate).
• Optional extras: CSP WeatherFX controller, SimHub telemetry, Discord bots for status pings.

Keep mods in version-controlled folders (Git LFS, rclone, or CM “Presets”) so the server and clients stay aligned.

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Hardware and Network Requirements

Players   CPU (Boost)       RAM      Storage     Upload Bandwidth
--------  ----------------  -------  ----------  ----------------
16        4c/8t @ 3.5GHz    8 GB     40 GB SSD   20 Mbps
32        6c/12t @ 4.2GHz   16 GB    60 GB NVMe  50 Mbps
64        8c/16t @ 4.5GHz   24 GB    80 GB NVMe  100 Mbps

• Strong single-core speed is vital for physics threads.
• NVMe storage shortens load times for huge traffic packs.
• Traffic AI adds CPU overhead; reserve 20-25% headroom.
• Enable DDoS protection and low-latency routing (players sync positions multiple times per second).

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Hosting Options

• Managed host (easiest): Mamba Host, GTX, Nitrado. Benefits include instant provisioning, traffic-friendly bandwidth, automatic backups, and panel-based CSP toggles.
• Self-host VPS/dedicated: Full control but requires manual port management (TCP 8081, UDP 9600/9601) and security hardening.
• Hybrid: Run lobby on managed hardware, mirror mods via Git or rclone to keep local testing in sync.

Managed providers shine when you need 24/7 uptime, DDoS mitigation, and quick mod rollouts.

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Build Your Mod Pack

1. Choose your map (e.g., Shutoko Revival Project v0.9.2). Verify AI lanes exist or plan to generate them.
2. Collect car packs:
   • Player cars (tuned, drift, police) in content/cars.
   • Traffic cars with low-poly models to conserve CPU/GPU.
3. Assemble required CSP configs (extension/config/tracks/loaded/yourtrack.ini).
4. Bundle weather and PPFilter presets so every driver gets the same sky and lighting.
5. Document dependencies in a README_sync.md explaining installation via Content Manager > Settings > Content > Install from folder.

Export the mod pack as a single .7z archive or use CM “Share” to produce a download link with checksum metadata.

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Server Installation & Configuration

1. Install binaries:
   • Windows: Copy Assetto Corsa Dedicated Server from Steam Tools to C:\ACServer.
   • Linux: Use SteamCMD (app_update 302550) to /opt/acserver.
2. Copy mods into content/cars, content/tracks, and extension inside the server directory.
3. Configure server_cfg.ini:

[SERVER]
NAME=Shutoko Traffic Cruise
PASSWORD=
ADMIN_PASSWORD=admin123
UDP_PORT=9600
TCP_PORT=8081
MAX_CLIENTS=48
REGISTER_TO_LOBBY=1
PICKUP_MODE_ENABLED=1
LOOP_MODE=1
UDP_PLUGIN_LOCAL_PORT=11000
SEND_BUFFER_SIZE=0

[RACE]
TRACK=srp_shutoko
CONFIG=inner_loop
SUN_ANGLE=24
WEATHER=sol_clear
LAP_NUMBER=0
TIME_OF_DAY_MULT=5

4. Define entry_list.ini with player slots and car restrictions:

[CAR_0]
DRIVER_NAME=Traffic Placeholder
TEAM=AI Traffic
MODEL=ac_traffic_toyota_prius
GUID=AI
MODEL_CONFIG=base
SPECTATOR_MODE=0

5. Launch with acServer.exe (Windows) or ./acServer (Linux). For managed panels, paste configs into the web UI and click Start Server.

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Traffic Logic & AI Lanes

• Ensure each track folder contains ai/ai_lane.ai, ai/fast_lane.ai, and data/traffic.json.
• Use the CSP Traffic Planner (Content Manager > Tools > Traffic Planner) to:
  1. Import the track.
  2. Mark spawn points, speed limits, and lane directions.
  3. Export traffic.json with trafficCarClasses matching your traffic car IDs.
• Optional: Create dedicated police.json or delivery.json groups for special spawns.
• Enable CSP > New AI Behavior > Allow traffic on both server and client to avoid desync.

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Syncing Mods with Players

• Content Manager auto-sync: Upload your preset to CM’s Server Manager. When players join, CM will fetch missing cars/tracks automatically.
• Version hash: Prefix mod folders with version numbers (srp_shutoko_v0.9.2). Update the server message of the day with the required version.
• Download mirrors: Host the pack on Google Drive, rclone-backed object storage, or Mamba Host’s CDN. Provide the link in Discord announcements and the server welcome message.
• Integrity checks: Use CM’s “Analyze missing content” before launch so all clients match server files.

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Performance & Stability Tuning

• Set TICK_RATE=60 in server_cfg.ini for smoother traffic updates; drop to 50 if CPU usage spikes.
• Adjust CLIENT_SEND_INTERVAL_HZ=18 for players on slower connections.
• Keep MAX_BALLAST_KG=0 to prevent unintended physics changes.
• In CSP Settings > Traffic, limit concurrent AI vehicles (e.g., 80) and reduce spawn distance for dense maps.
• Schedule restarts every 6-8 hours to clear memory fragmentation.
• Monitor CPU load; aim for <75% utilization during peak traffic to prevent warp.

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Admin Tools & Monitoring

• Remote kick/ban: Use asserver console commands or the managed panel. Example: /kick 76561198000000000.
• Live logging: Tail server/out.log to watch join/leave events and CSP traffic warnings.
• Discord webhooks: Post server status (uptime, player count) to a management channel. Mamba Host exposes webhooks out of the box.
• Updates: Track CSP nightly builds in a staging environment before pushing to production.

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Common Issues & Fixes

Issue	Cause	Fix
Clients stuck on loading screen	Missing traffic car or mismatched CSP version	Share updated mod pack and enforce CSP minimum via server message
Rubber-banding traffic	Tick rate too low or high latency	Increase TICK_RATE to 60 and migrate to lower-latency host
AI cars despawn	Traffic.json lane naming mismatch	Rebuild lanes with CSP Traffic Planner and ensure laneType matches
Weather desync	Clients running different Sol preset	Provide Sol configuration and enforce via CM preset
Server crash on restart	Corrupt entry_list cache	Delete /cfg/entry_list.ini cache and regenerate

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Launch Checklist

• Ports 9600 UDP and 8081 TCP open and DDoS-protected
• server_cfg.ini validated (names, track, passwords, tick rate)
• entry_list.ini synced with allowed cars
• Traffic pack version documented and distributed
• Content Manager preset tested on staging lobby
• Backups for configs, mods, and CSP settings
• Status bot posting uptime to Discord
• Restart schedule configured

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Host with Mamba Host

Mamba Host’s Assetto Corsa plans are optimized for traffic-heavy sessions:

• Ryzen 9 CPUs and NVMe storage designed for 60+ tick rate cruising
• One-click Content Manager sync and CSP toggles in the panel
• Automatic daily backups and easy mod rollbacks
• Global Anycast DDoS protection with <40ms peering in NA/EU
• 24/7 support staffed by sim racing specialists

Start an Assetto Corsa Traffic Server

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Last updated: October 29, 2025