There's three different things I see on the road.
1. I think those are the receivers for emergency vehicle override signals.
2. Traffic Monitoring Cameras
3. Red Light Ticket Cameras
View attachment 3366
Its called an Opticom. It does override the traffic signals in order of priority:
1-Trains
2-Fire
3-Police
4-Mass Transit (some places put them on buses to move them along, making it more efficient.)