Hi!
I was wondering what are the antennas on the Traffic Lights for? Anyone knows?
And If i can read the crosswalk Signal, If there is a Signal for that.
Greetings
In Portugal they are not antenas, they are sensors to detect cars/people so that they can adapt the lights acordingly - example if the are no people on a cross-road the time for it to change to green it will be way longer than it will be if the sensor detect people. Same for cars. Are you sure the ones you have are antennas ?
In some countries there are system in place used by emergency cars / ambulance / police triggered by remote that will change the light to green on a designated interception to be used in emergency to provide priorirty on that road/way, maybe that is what you have ? If so your best bet would be to have access to the device that trigger the emergency behaviour like the ambulance/police device/radio. In Portugal we don’t have that and sensors on traffic lights are for what i described plus in some cases to act as radar and tur the light to red if cars are over-speeding. Also they are using cameras to take photo of license plate in case of infraction.
There are different systems for that („LSA Vorrangschaltung“)
Car2X is used sometimes; in combination with OpenTraffic System 2. very very few Infos about
Public Transport uses telegrams (sometimes alone, sometimes only only in combination with IR Beacons)
To learn more about radio telegrams: here’s some explanation of VDV
https://www.vdv.de/voev-04-05-1-erg.pdfx
Yes, it’s old, but probably still commonly in use.
(Hint: R09.1)
Edit: public services (BOS) use very different systems also, if any at all.
Some cities have antennas at big intersections for that. But I think mostly digital radio (TETRA) for that.
here in Qatar we have two systems, first one is pedestrian crossing sensor which uses infrared to automatically detect pedestrians and change the green signal. The second system is Emergency Vehicle Preemption System (EVPS) , which allows ambulances and Civil Defense trucks to override the signal and change it to green, as far as I know here they use OPTICOM system, Im not sure about what signal does it use.
Unfortunately the frequency for the systems that public transport uses in Germany, is basically outside of the Flippers spectrum. These systems (RBL for example) work on frequencys from about 145 to 155 MHz. I checked the datasheet of a receiver on a traffic light today.