Cool, but it there's no links for more info, and it doesn't seem to work in the USA at all.

The site is definitely lacking. It's half in German, half in English.

The concept is that there is this protocol called ITS-G5, which is a European profile of 802.11p. Vehicles and traffic infrastructure can transmit telemetry on 5 GHz. Other vehicles and traffic infrastructure can use it for situational awareness.

This website collects that data using local receivers and aggregates it onto a map, similar to what website like ADSB-Exchange do with ADS-B.

What is concerning is that vehicles appear to broadcast a MAC address. Does this mean that ITS-G5, 802.11p, and C-ITS could be used for persistent tracking?

Reading the translation of the talk, public transport vehicles have a persistent MAC but for private cars the MAC address changes every 15 minutes.

As discussed in the video they are not resetting the packet sequence number though, making it easy to match them with the other data transmitted.

That still doesn't seem very private.

For a vehicle with a highly visible unique identifier on the front and rear? In my country basically every private carpark has ANPR cameras, the tech is dirt cheap now.

Particularly anywhere rural or off the beaten path

You wouln‘t really have the kind if hardware there. The communication relies on a multi hop mesh that would‘t work anywhere without sufficient coverage.

You do know you have a unique ID displayed on a big tab on the vehicle, right?

> What is concerning is that vehicles appear to broadcast a MAC address.

Somewhat related: 'Your car’s tire sensors could be used to track you': https://networks.imdea.org/your-cars-tire-sensors-could-be-u...

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What about the traffic lights on the map do they also have transmitters?

Yes, they also have transmitters. The traffic lights send out MAPEM and SPATEM messages. They describe the layout of the lanes at the intersection as well as the red/green phase timings of the signal.

In Graz, the city where the authors live, there are 165 of such signals planned.

This should be a top level comment as it has a ton of useful info and can be voted to the top.

Did they re invent APRS?

The project was shared as part of a talk at Graz Linux Tage. You can find it here, unfortunately it is only available in German

https://media.ccc.de/v/glt26-688-c-its-mit-einem-esp32-ampel...

Happy to see this popping up here, I watched the Linux Tage talk last week. The demo just kept getting better and better, to a point where the audience just interruptively cheers and claps away. I know nothing about the contents, but this warmed my heart. True hacker project!

Is there a link to the hardware they mention in the description?

They built their own circuit board but the core module that does the 802.11p is just a ESP32-C5

Yes, I understand that. The translation makes it sound like they have published the software and design, or are somehow making boards available.

>To improve coverage, we need your support! We have built a board with *ESP32-C5* and *PoE* that allows you to capture *C-ITS* packages yourself, and provide us for our face-up card, or process it yourself.

Edit: found it, https://codeberg.org/opentrafficmap

Pastebin here containing AI-generated English translation, LGTM: https://pastebin.com/fK5Atwzg

It's based on Car2X/Vehicle2X data that's sent unencrypted and can be received with chips you can order from China.

Will be interesting to see how it fares when it does come to the US. It seems like there are some cars that already have the tech installed. But the US is allegedly more interested in the cellular version, which I am guessing is not as easy to pick up with a simple receiver?

My gut feeling is that this seems like one of those things likely to face a lot of backlash when it becomes widely known.

I guess we only find out if some people order those chips and check if there is some data. From my understanding the idea is the same like maps showing air planes or ships (for ships it’s AIS). So without volunteers/pioneers who participate we won’t know. It seems like traffic lights and trams also can send data.

If I had a dollar for every time I've seen an American on the Internet assume that anything published in the English language must be US-centric...

You still wouldn't have nearly as many dollars if you subtracted the times those people were correct in that assumption. Personally I assumed the site would be global. It doesn't have any info though, so I rely on finding out somewhere else I guess.

> Personally I assumed the site would be global

The only reason you would assume a site would be global is if your definition of "global" is "works in the US" & you never bother to check for support of other countries. I live in the anglosphere outside of the US & I encounter more than enough US-only web projects for that not be to a default assumption I hold.

Most sites are not global - it's very odd to assume they would be.

Another reason could be that calling this OpenTrafficMap gives an impression that it is similar to OpenStreetMap, which is global.

Fun fact: OpenStreetMap started out with maps of only the UK. OpenTrafficMap does support data from all around the world.

OSM launched as a London / UK project. Even today, it's a lot more comprehensive in some parts of the world than others.

If I got the impression that it was like OSM, that would give me the impression that it is only as global as my contributions to it (which is what lead to OSM becoming global).

Expecting support globally is of course unreasonable. Expecting it to be designed to be somewhat location-agnostic for contributors and including some obvious docs (which could just be "coming soon" or "here's what we need to expand") is pretty reasonable to me.

I don't get why there isn't even a stub repo for a mobile app to contribute with. Or am I just not finding it?

The repos are there: https://codeberg.org/opentrafficmap

https://codeberg.org/opentrafficmap/its-g5-receiver: "Current ordering situation

(as of 2026-04-23)

After the talk on Grazer Linuxtage (media.ccc.de, youtube.com) we got many responses from people also wanting to buy this receiver. We fixed a few issues of the first revision and ordered 200pcs of Revision 2.

We expect the 200pcs to arrive in the first week of May, 2026. The cost of one complete receiver (excluding case and mechanical parts) is about 20 €.

If you want to purchase a receiver PCB, please contact us at the email liked in the Imprint/Impressum of opentrafficmap.org"

That's for a hardware receiver. It does not appear to have mobile app or API doc accompanyment or a doc on what is needed for expansion. I would imagine that there is a minimum critical mass and municipal buy-in for such devices to work. Theoretically, mobile apps would require far less barriers to start being useful.

It seems pretty weird to use all English words in the domain for a service that offers no English translations and operates in no English speaking countries.

The map is based on international standards and technically it does not restrict locations to German speaking countries.

The authors of this project also shared that they intend on publishing more around this project. This seems to be mostly an early demo that was intended for the live event.

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The Germans and Danes and Swedes and Norwegians I see on the Internet developing and publishing software often have a better grasp of the English language than many born in the USA Americans.

That's true for Scandinavians, Germans are not as gut.

Ja ja, maybe not as gut as the Scandinavians, but still better than many US Americans.

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Is expecting something to work in the US the same as expecting it to be US-centric?

Conversely, if I had a penny for every time someone complained about Americans... ;-)

That's one way to get rid of our (US) pennies now that they're useless!

I did scroll across to the UK and was disappointed that there's none for here.

But I'll probably add my own receiver soon!

This is an American site to be fair. Mapbox is also an American company.

It does have an English name, so why the surprise?

OpenStreetMaps works in the US and much of the rest of the world.

It's entirely reasonable to expect that a project with an extremely similar name would also work in most of the world, which just happens to include the USA.

I mean I don’t anyone thought this was in the US since the UI is not in English. Maybe it’s more of, this neat, wish we had it here?