See the cars talk
V2X2MAP is an app for iPhone and Android that receives and maps ITS-G5 / V2X traffic: the 5.9 GHz IEEE 802.11p messages cars and roadside infrastructure send to coordinate.
Android Auto soon** Android Auto comes with the next update, which is currently awaiting approval on Google Play.
Three steps. Then drive.
Plug a $20 ESP32-C5 dev board into your phone, drive somewhere with modern infrastructure, watch the CAMs, DENMs and SPATEMs roll in.
Install V2X2MAP
Get it from the App Store or Google Play: on iPhone via Bluetooth LE, on Android via USB-OTG or Bluetooth LE.
Connect the ESP32-C5
Plug it in over USB-OTG or pair via Bluetooth LE. The app detects the board and flashes the firmware automatically, in under a minute. Which board?
Watch the traffic roll in
Reception starts immediately. Every CAM, DENM and SPATEM lands on the live map.
Cars are already talking.
Modern cars and roadside units (RSUs) broadcast standardised safety messages on the dedicated 5.9 GHz V2X band.
V2X2MAP captures these in promiscuous mode, decodes the GeoNetworking headers locally and plots each message as a colour-coded marker on an OSM map. No cloud round-trip required. Everything runs on the phone.
Cooperative Awareness
Position, speed and heading of a vehicle.
I'm here, going X km/h
Decentralised Environmental Notification
Warnings about events on the road.
Hazard ahead!
Signal Phase + Timing
What a traffic light shows and for how long.
Traffic-light countdown
Map data
Lanes and connections of an intersection.
Intersection geometry
Know the light before you see it.
Signalised intersections broadcast their phases (SPATEM) and lane layout (MAPEM). V2X2MAP picks out the signal heads for your approach and shows them at the top of the map, one per direction.
- Left, straight and right, each with its own arrow
- Countdown when the intersection sends its timing
- Lanes on the map coloured by their current signal
Everything on one screen.
Live map, traffic-light phases, intersection lanes, radar, statistics and range measurement: all decoded on your phone.
← swipe for more →
Room for more on a tablet: map and live log side by side.
Built for the road.
Live map
OSM map, colour-coded markers per message type, heading-aware arrows for vehicle CAMs, auto-fade so the screen doesn't drown.
Auto-follow
Speed-adaptive zoom: 18 standing still, 14 above 80 km/h. The map keeps your dot centred.
Geiger-counter mode
A short tick on every frame, a higher beep + buzz on a DENM hazard. Drive with eyes forward.
BLE + USB
The C5 streams raw 802.11 frames over USB-Serial-JTAG and Bluetooth LE, time-shared with the sniffer.
Offline maps
OSMdroid tile cache up to 600 MB. Pan around online once, then go offline.
Recording & replay
One tap writes every frame to an .itsg5 file for later replay and analysis.
MQTT bridge
Optionally re-publish frames over MQTT. Default broker is the public OpenTrafficMap one; custom brokers configurable.
Localised UI
English by default, German for German devices. Both translations ship in the APK.
V2X2MAP for iPhone.
The fully native iOS app is now available on the App Store. Same receiver, connected over Bluetooth LE, plus lane-by-lane traffic lights drawn right into the map.
These clips are replays of a real drive through Stuttgart.
On your car's screen.
Traffic lights and hazard warnings, big and glanceable on the dashboard. Apple CarPlay works today; Android Auto comes with the next update, which is awaiting approval on Google Play.
Knows the local signal rules — red-amber or not, flashing arrows, km/h or mph, left- or right-hand traffic. Picked automatically by country.
One board. That's it.
The board supports 5.9 GHz IEEE 802.11p out of the box; the firmware drives it as a sniffer and forwards captured frames to your phone.
Waveshare ESP32-C5-WROOM-1 dev board
ESP32-C5 (Wi-Fi 6 + BLE 5) breakout with external 2.4/5 GHz antenna and pin headers. The exact board V2X2MAP is built for. Multi-protocol RF capable of 5.9 GHz IEEE 802.11p sniffing.
- Wi-Fi 6 + BLE 5
- 5.9 GHz 802.11p sniffing
- Firmware flashed by the app
Alternatives with built-in antenna
Smaller and cheaper, no antenna to mount. Same firmware, and each has a matching case. Range is a little shorter than with the external antenna.
A case for the car
Designed and printed in-house, an exact fit for each board. The lids snap on without screws, and the QR code on the lid leads straight to the app.
Soon on EtsyBoards, cases & mounts →
Optional accessories
Antenna upgrades for more range, plus what you need to run the receiver in the car.
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From the street to your screen.
A band of its own.
V2X safety messages live in a dedicated slice of spectrum at 5.9 GHz. In Europe the ITS-G5 band (5855–5925 MHz) is split into channels by purpose. The control channel carries the most safety-critical traffic.
What is V2X?
Vehicle-to-everything explained: V2V, V2I, V2N, V2P and why cars talk.
Read →ITS-G5 vs C-V2X
The two competing V2X radios (Wi-Fi-based vs cellular) compared.
Read →Message types
CAM, DENM, SPATEM, MAPEM, IVIM and CPM: what each one does.
Read →Frequency spectrum
How the 5.9 GHz band is split across Europe, the US and China.
Read →Green light. Get the app.
Everything runs in the V2X2MAP app: no desktop tool, no manual setup. On Android it even flashes the ESP32-C5 firmware for you; on iPhone you flash the board once in the browser at v2x2map.com/flash.
* Android Auto comes with the next update, which is currently awaiting approval on Google Play.
- 1Install from the App Store or Google PlayiPhone with Bluetooth LE, or any Android phone with USB-OTG or Bluetooth LE.
- 2Connect the ESP32-C5Firmware is flashed automatically, in under a minute.
- 3Watch the traffic roll inReception starts immediately. Every CAM, DENM and SPATEM lands on the live map.
Legal
Receiving and forwarding ITS-G5 radio data may be subject to national telecommunications law and data-protection law. The Android app shows a disclaimer on first launch. Use at your own risk.