Black thingy on top of Traffic Lights?

Question

I was wondering what are those black camera looking things on top of traffic lights i saw different kinds

1 kind was right next to the traffic light
2nd kind was right on top of the traffic light it seemed like it was connected
3rd kind was below the traffic light

i was wondering are these the same thing or different? and what are they?

Answer 1

Actually, because the devices were near the signal heads then they were more than likely not cameras at all.

Traffic Signals can be actuated in a few different ways.

1.) There could be inductive loops in the pavement that sends a signal to the cabinet to let the controller know that a vehicle is on that approach. This is known as putting a call into the cabinet.
2.) These could be microwave detectors. These send out microwaves that rebound off of the ground or a car is one is present. These microwaves then flow back to the sensor and if there is a car present then the waves arrive sooner than they would have if there were not a car. If this happens "a call" is put into the controller. I believe this is what you are seeing when the unit is beside the signal head.
3.) There is strobe pre-emption for emergency vehicles but they would only be located on routes where constant emergency vehicles would be traveling, so, next time you see them attached to the signal head then look around for a hospital, police station, or a fire station.
4.) If you see a camera at a signal it does not automatically mean that it is viewing the cars (like big brother). A lot of places use camera detection and the cameras only feed into the cabinet that controls the intersection.

I work for the NCDOT and I am over the traffic signals department as well as the traffic services department.

Answer 2

Here in Colorado we have and I forget the name of it, but on all emergency vehicles there is a strobe facing forward and yes it flashes at a certain frequency. When the strobe is detected it changes the light to a 3 way stop and green for the approaching emergency vehicle. The strobe is about 5 inch by 5 inch by 3 inch deep. Do not install one here about 5 or 6 months ago they busted a drive with a set up to do that.

Answer 3

If you're talking about the little sensors, they are devices that allow emergency vehicles to manipulate traffic signals going through intersections. An emergency vehicle has a strobe light that operates at a frequency that these devices recognize.

Answer 4

They are surveillance cameras watching for accidents, trffic violations, and someplaces use them for the news to report hoeavy traffic areas. They mount them in differant places to get differant angles of each intersection.

Answer 5

If they are cameras, they are used by police to photograph and ticket speeders or those who ''run'' red lights. In Cleveland (OH), the cameras are off to the side of the road and look like space debris from a rocket ship.

Answer 6

Well all of them r cameras. one takes pic of ur plates incase u run a red light, the other takes a pic of the windshield but i don't know wat the last 1's for

Answer 7

They are exactly that. Cameras