There was a street repair work at my way to work. The street the workers put up a set of automated wireless traffic lights to control the flow of traffic during the works (the road was reduced to one line where cars can drive to opposite directions at different times).
Here is a closer view of the traffic light used:
I had earlier tested Software defined radio with USB DVB-T stick, so this could be an interesting idea if I could find the the transmission and even decode it like signal hackers have done. Due other this and that I could not spend time on this idea at the moment.
But I did a Google search on the issue instead. So I found Reverse Engineering Wireless Mobile Traffic Lights and Reversing Mobile Traffic Lights articles that tells pretty much what I expected to test. Engineering Wireless Mobile Traffic Lights tells that similar traffic lights used two signals at around 170 MHz that included data FSK1200 modulated between 1200Hz and 2400Hz.
There is even Talk by Micheal Ossmann at Toorcon 2015: Rapid Radio Reversing touching the subject.Check out that video:
After those findings I still have question is it too easy to hack traffic lights?