First off, I don't know if this is the correct sub-forum for this. Moderators, I apologize in advance and please move it to the correct sub-forum, if necessary. Okay where is the best place to get up to speed on traffic preemption systems? For example, the specific frequencies used, pulse width, etc. I am finding quite a bit, but still looking for more.
https://en.wikipedia.org/wiki/Traffic_signal_preemption
https://ops.fhwa.dot.gov/publications/fhwahop08024/chapter9.htm
https://en.wikipedia.org/wiki/Traffic_signal_preemption
https://ops.fhwa.dot.gov/publications/fhwahop08024/chapter9.htm