In my experience, the congestion data is not the issue: even with the split across Google / TomTom / Here / Apple / some hyperlocal alternatives, everyone seems to have reasonably good idea where the traffic jams are. Having up to date POIs is a different can of worms only solved by Google, not by some clever algo, but through the sheer brand recognition. They're the only ones that have this data fed to them by POI owners.
Idea: an open website/app that updates POI information on every known platform simultaneously. To POI owners it would be a win because it means their info is reaching more people but there's not much extra work. The hard part is spreading the word, but I don't see why an open project's donations can't go towards marketing. The marketing material can also be used to promote the existing open platforms like OSM and some of the open review websites(mangrove.reviews and lib.reviews for example), such as sending free window stickers to POI owners that say "Review us on **!".
Well, Google has the most popular OS. Tomtom is not far from being the OS of lots of cars. Here, too. It's owned by Daimler/BMW/Audi (sold for 3 billions). Apple has the second most used mobile OS.
So yes, for these huge actors, it's quite easy to create congestion data.
The vast majority of POI churn information comes from streetview + machine learning object detection + automatic change detection + human verification. There are many clever algorithms in play through the entire pipeline. As moats go, its probably bigger than search.
You forgot the massive user base of Google. Users through comments are the first to tell Google that the POI changed. And shop owners are often the first users to worry.
How would you overcome the data source trust issue? In open data collection you either fingerprint the data to ensure validity or you anonymize the data to provide security, but striking the balance between the two seems like the biggest of hurdles in an effort like this.
The risk of the data being invalid seems as risky as the privacy implications in this case.
Hi, as the developer of opentrafficmap.org I can tell you that nearly all stations (traffic lights, cars, busses, trams, etc.) have a certificate, that can be validated against a trust chain managed by the EU. You can see the signature of you click "View JSON" on a tracked object
Good question. If one strong national actor (map app, for instance) could publish its live dataset, without even mixing with others, this could already be used.
https://cartes.app. Based on OSM of course, but OSM is just a geographical database, with lots of incomplete UIs built on top by the community. Cartes is one of them, we're trying to make it complete and modern :)
That looks pretty cool - sorry to have a complaint immediately:
When opening the map on Firefox/Linux zooming to like a France-size view and then not doing anything, the view keeps scrolling up and down relatively slowly, but very annoyingly.
Zooming all the way out, it looks like the globe is jiggling back and forth ever so slightly, but continually.
I've recently seen this happen on another mapping application ( cannot remember which one) so it's probably in down the stack somewhere in a library you are using.
For a while I tried creating traffic-light-free bicycle routes from my home in the suburbs to my office in Amsterdam center (because intersections, especially with trams, can sometimes take a long time.
Unfortunately there was no API with data on which intersections have traffic lights and I had to build these routes manually in Strava using satellite images.
I did learn in the process that some traffic light data is actually available from the government, but only for selected partners. The Flitsmeister app for example has it and shows at some traffic lights how long it will take for the light to turn green (in a car, not on a bicycle)
OpenStreetMap has traffic lights (at least in my municipality in the Netherlands) so it might be usable for this purpose.
Also, https://routeplanner.fietsersbond.nl/ has options for different route types including an option to avoid traffic lights if a reasonable alternative is available.
Rotterdam is using rain data to asjust traffic lights. Bicycles are waiting less at intersections. They also make the amber light longer to give you time to break for farther away and avoid a fall.
How does the hardware work? It seems like there isn't any radio hardware other than the ESP, so that can natively receive the ITS-G5 messages? Why not just use an ESP board with native ethernet then?
Found out about this today, up until now 802.11p hardware is very expensive, and so you cannot easily do anything with V2x messages like CAM or SPAT, but the fact this was done with sub £20 hardware is really interesting.
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?
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.
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.
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.
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!
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.
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.
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.
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.
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?
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.
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.
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.
This is an English translation from the talk description:
Did you know that if your car supports *Car2X* via *ITS-G5*, it transmits its exact GPS position, speed, longitudinal and lateral acceleration, pedal positions, length and width, and much more—all unencrypted—up to four times per second on a 5-GHz band?
Trams in Graz also transmit this data, including their line numbers. This allows us to track the trams in real time and display them on a map.
Many traffic lights in Graz now support *C-ITS* and transmit data every second regarding the exact configuration of the lanes, the current signal status, and when the next phase is expected.
With an *ESP32-C5*, we can already receive this data from a distance of several hundred meters.
We’ll show you how we collect and process this data. On a live map, you can see (within the coverage area) trams, the color of the traffic lights and when they’ll change next, and which cars equipped with Car2X are currently driving and at what speed.
Using Grafana, we display historical data on traffic light cycles and statistics, such as wait times at crosswalks and in traffic lanes. We also give you access to the collected data for your own analysis.
To improve coverage, we need your help! We’ve built a board with *ESP32-C5* and *PoE* that lets you capture *C-ITS* packets yourself and share them with us for our open map, or process them on your own.
The night bus service only runs the nights "before" Saturday and Sunday[1]. It's a small university city with 300k population (600k greater metropolitan area).
> It's a small university city with 300k population
Made me smile, I'm from outside a city we used to call "big city" when I was growing up, it had ~110K population and is the 9th largest in the country or something :P Anyways, that city still has night service, so not sure why a city with three times the population wouldn't, especially if it's a university city.
We need global open congestion data. At least on the european scale.
It's important so that alternatives to Google Maps and Waze (Google) can emerge.
To create congestion data, one needs to own an OS with location tracking, or be an international mobile network. Won't happen.
[disclaimer : I work on an open source alternative to big tech's maps]
In my experience, the congestion data is not the issue: even with the split across Google / TomTom / Here / Apple / some hyperlocal alternatives, everyone seems to have reasonably good idea where the traffic jams are. Having up to date POIs is a different can of worms only solved by Google, not by some clever algo, but through the sheer brand recognition. They're the only ones that have this data fed to them by POI owners.
Idea: an open website/app that updates POI information on every known platform simultaneously. To POI owners it would be a win because it means their info is reaching more people but there's not much extra work. The hard part is spreading the word, but I don't see why an open project's donations can't go towards marketing. The marketing material can also be used to promote the existing open platforms like OSM and some of the open review websites(mangrove.reviews and lib.reviews for example), such as sending free window stickers to POI owners that say "Review us on **!".
Well, Google has the most popular OS. Tomtom is not far from being the OS of lots of cars. Here, too. It's owned by Daimler/BMW/Audi (sold for 3 billions). Apple has the second most used mobile OS.
So yes, for these huge actors, it's quite easy to create congestion data.
The vast majority of POI churn information comes from streetview + machine learning object detection + automatic change detection + human verification. There are many clever algorithms in play through the entire pipeline. As moats go, its probably bigger than search.
You forgot the massive user base of Google. Users through comments are the first to tell Google that the POI changed. And shop owners are often the first users to worry.
How would you overcome the data source trust issue? In open data collection you either fingerprint the data to ensure validity or you anonymize the data to provide security, but striking the balance between the two seems like the biggest of hurdles in an effort like this.
The risk of the data being invalid seems as risky as the privacy implications in this case.
Hi, as the developer of opentrafficmap.org I can tell you that nearly all stations (traffic lights, cars, busses, trams, etc.) have a certificate, that can be validated against a trust chain managed by the EU. You can see the signature of you click "View JSON" on a tracked object
Good question. If one strong national actor (map app, for instance) could publish its live dataset, without even mixing with others, this could already be used.
Authorities could pay them for this service.
What is the OS alternative? OSM?
https://cartes.app. Based on OSM of course, but OSM is just a geographical database, with lots of incomplete UIs built on top by the community. Cartes is one of them, we're trying to make it complete and modern :)
That looks pretty cool - sorry to have a complaint immediately:
When opening the map on Firefox/Linux zooming to like a France-size view and then not doing anything, the view keeps scrolling up and down relatively slowly, but very annoyingly.
Zooming all the way out, it looks like the globe is jiggling back and forth ever so slightly, but continually.
I've recently seen this happen on another mapping application ( cannot remember which one) so it's probably in down the stack somewhere in a library you are using.
Yes, known bug, we've discovered it recently. Here's how to unbreak the map. https://codeberg.org/cartes/web/issues/2095
Heh
> For privacy reasons we've made the planet shake a little bit
Thank you for the hint. We live in a very complex world...
I recently learned that with smart traffic lights cyclists can change traffic lights -https://nltimes.nl/2026/04/28/new-app-turns-traffic-lights-g...
For a while I tried creating traffic-light-free bicycle routes from my home in the suburbs to my office in Amsterdam center (because intersections, especially with trams, can sometimes take a long time.
Unfortunately there was no API with data on which intersections have traffic lights and I had to build these routes manually in Strava using satellite images.
I did learn in the process that some traffic light data is actually available from the government, but only for selected partners. The Flitsmeister app for example has it and shows at some traffic lights how long it will take for the light to turn green (in a car, not on a bicycle)
OpenStreetMap has traffic lights (at least in my municipality in the Netherlands) so it might be usable for this purpose.
Also, https://routeplanner.fietsersbond.nl/ has options for different route types including an option to avoid traffic lights if a reasonable alternative is available.
Rotterdam is using rain data to asjust traffic lights. Bicycles are waiting less at intersections. They also make the amber light longer to give you time to break for farther away and avoid a fall.
https://popupcity.net/insights/rotterdam-traffic-light-prior...
Codeberg link https://codeberg.org/opentrafficmap
How does the hardware work? It seems like there isn't any radio hardware other than the ESP, so that can natively receive the ITS-G5 messages? Why not just use an ESP board with native ethernet then?
They are doing it with the standard WIFI receiver. Currently they are sending the Wireshark dumps to a backend for processing.
According to their presentation they are working on a rust firmware to do everything on the board.
Found out about this today, up until now 802.11p hardware is very expensive, and so you cannot easily do anything with V2x messages like CAM or SPAT, but the fact this was done with sub £20 hardware is really interesting.
Fully agree. That's the most interesting thing about this.
I haven't seen a theme on OSM data look this modern and fresh before. Beautiful color palette and iconography!
It looks like Mapbox Standard [1]. While a free tier is available, most sites are going to need a paid plan.
[1] https://docs.mapbox.com/map-styles/standard/guides/
Can you try this one ? Though not as flashy, it's a step away from most OSM styles.
https://cartes.app/#13.13/47.06727/15.44801
I, for one, do like it. I usually prefer lighter themes, but this one would be more than ok for me.
Cool ! It's fully open source. Quite a complex TS style https://codeberg.org/cartes/web/src/branch/master/app/styles...
And its Tilemaker profile to generate the tiles : https://codeberg.org/cartes/serveur/src/branch/master/tilema...
It's a Mapbox theme
Agreed - it is very similar to Google Maps.
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.
Even our tires blast out IDs.
https://www.rtl-sdr.com/exploring-the-privacy-risks-of-tire-...
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...
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.
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.
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?
Huge performance issues for me trying to use it on Chrome. But I like the idea.
It will be nice if we everybody could just add own receivers, then it will be quickly cover more cities. But still nice project.
Ahh, it send automatically to website! "mqtts://cits1.opentrafficmap.org"
Wow, I am dreaming a live NYC traffic map
I don't get this at all. Is this a live view of the traffic lights, buses, and more? How do they get the data?
This is an English translation from the talk description:
Did you know that if your car supports *Car2X* via *ITS-G5*, it transmits its exact GPS position, speed, longitudinal and lateral acceleration, pedal positions, length and width, and much more—all unencrypted—up to four times per second on a 5-GHz band?
Trams in Graz also transmit this data, including their line numbers. This allows us to track the trams in real time and display them on a map.
Many traffic lights in Graz now support *C-ITS* and transmit data every second regarding the exact configuration of the lanes, the current signal status, and when the next phase is expected.
With an *ESP32-C5*, we can already receive this data from a distance of several hundred meters.
We’ll show you how we collect and process this data. On a live map, you can see (within the coverage area) trams, the color of the traffic lights and when they’ll change next, and which cars equipped with Car2X are currently driving and at what speed.
Using Grafana, we display historical data on traffic light cycles and statistics, such as wait times at crosswalks and in traffic lanes. We also give you access to the collected data for your own analysis.
To improve coverage, we need your help! We’ve built a board with *ESP32-C5* and *PoE* that lets you capture *C-ITS* packets yourself and share them with us for our open map, or process them on your own.
I wonder if this could be used to track location of the vehicle
Isn't that the point of the project? I'm seeing a bunch of tracked vehicles, although they all seem parked at the moment.
Does Graz not have night bus service?
The night bus service only runs the nights "before" Saturday and Sunday[1]. It's a small university city with 300k population (600k greater metropolitan area).
[1] https://www.verbundlinie.at/en/customer-service/arriving-in-...
> It's a small university city with 300k population
Made me smile, I'm from outside a city we used to call "big city" when I was growing up, it had ~110K population and is the 9th largest in the country or something :P Anyways, that city still has night service, so not sure why a city with three times the population wouldn't, especially if it's a university city.
If it's not able to support a robust bus system, it's not a city, just a really big town.
Am I the only one here who thinks this is intrusive?
>WebSocket getrennt
Hug of death? Nothing loads.