It has been years since I have seen a fire truck get a green light through preemption. It probably varies by jurisdiction, but around here the preemption just

It has been years since I have seen a fire truck get a green light through preemption. It probably varies by jurisdiction, but around here the preemption just causes the entire intersection to go red. Then the emergency vehicle can navigate across carefully. In addition to being basically useless as a trick these days, it is also trivially easy to detect an IR strobe being used, and the penalty can be hefty. Fun fact: In some places, there are strobes on the signal that activate when it has been preempted, to let everyone know an emergency vehicle is coming through.