OpenTrafficMap

Original Article ↗ Hacker News Discussion ↗

OpenTrafficMap is an experimental project that uses cheap ESP32-C5-based receivers to capture unencrypted European ITS-G5 (Car2X) broadcasts from cars, trams, and smart traffic lights and visualize them live on a map, currently focused around Graz. Commenters highlight how unusual and exciting it is to do vehicle-to-everything (V2X) monitoring with sub‑€20 hardware, but note the site’s rough edges, limited geographic coverage, and lack of English documentation. The project also raises concerns about vehicle tracking and privacy, while prompting broader calls for open, global congestion and traffic data as an alternative to closed ecosystems like Google Maps.

Project & Data Source

  • OpenTrafficMap visualizes live traffic lights, trams/buses and Car2X-equipped cars using C-ITS / ITS-G5 (European 802.11p profile) data.
  • Vehicles broadcast unencrypted telemetry on 5 GHz: GPS, speed, acceleration, pedal positions, size, etc., up to 4 times per second.
  • Smart traffic lights transmit lane configurations and current/next signal phases (MAPEM/SPATEM messages); Graz reportedly plans ~165 such signals.
  • Data is collected by receivers and fed to a backend (currently via Wireshark dumps; Rust firmware is in progress). Aggregation is similar in spirit to ADS-B / AIS tracking sites.

Hardware & Openness

  • Core receiver: ESP32-C5, using its standard Wi‑Fi radio to capture ITS-G5 messages; a PoE board design is provided.
  • Hardware cost is ~€20 per receiver, and ~200 boards were ordered after a conference talk.
  • Repos and docs are hosted on Codeberg; users can contribute by running receivers that push to an MQTT endpoint.
  • Some commenters suggest complementary ideas like mobile apps for easier scaling; others note that’s outside the current project scope.

Coverage, Language & UX

  • Map works mainly in parts of Europe (e.g., Graz). Some users expected global coverage or at least US support and are disappointed.
  • Debate over whether it’s reasonable to assume a project with an English name and “Open…Map” branding is global.
  • Site is described as early-stage: partly German, partly English, sparse documentation, performance issues, and occasional “hug of death.”

Privacy, Tracking & Intrusiveness

  • Concern that persistent MAC addresses enable tracking. Thread notes:
    • Public transport vehicles appear to use persistent MACs.
    • Private cars change MAC every ~15 minutes, but packet sequence numbers may still allow correlation.
  • Comparison is made to existing tracking vectors: license plates, tire pressure sensors, ANPR cameras, and cheap radio loggers.
  • Some find the project exciting “true hacker” work; others explicitly call it intrusive or foresee backlash once widely understood.

Broader Mapping & Traffic Context

  • Strong interest in open, global congestion data as an alternative to Google/Waze, but skepticism about feasibility without OS-level tracking or carrier data.
  • Related projects like Cartes (OSM-based, open-source maps) are discussed, including styling, data freshness, and bugs.
  • Cycling and smart traffic light use cases (priority for bikes, rain-aware timing) are mentioned as promising applications of such data.