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Brian Cline
New member
Username: Briancline

Post Number: 1
Registered: 02-2008
Posted on Friday, February 22, 2008 - 03:00 pm:   

Hello, I have a few questions about what exactly some of the various traffic monitoring/sensing devices around Frisco do. Specifically, I am interested in what these devices are and what they do:

1) The cameras mounted on white poles above traffic signals;

2) The small black devices sitting next to these cameras, sitting directly on the horizontal traffic signal support beam and aim at oncoming traffic;

3) The small white lights that turn on during a red light and back off during a green light (sometimes enclosed in a small cage), affixed to the top of the vertical beam of a traffic signal pole directly under where the horizontal and vertical beams meet.

Can anyone shed some insight as to what each of these do? Thanks.
 

Todd Renshaw, Chief of Police
Moderator
Username: Todd

Post Number: 372
Registered: 01-2002
Posted on Friday, February 29, 2008 - 07:45 am:   

1) The cameras on white poles are the signal actuator cameras. They detect traffic much the same as the magentic loops in the pavement. They control the cycling of the traffic light.
2) Those small black devices are Opticom sensors. Special lights mounted on ambulances and fire trucks flash and those black devices receive the flash and change the light green for the emergency vehicles.
3) Those small white lights are downstream lights that allow a police officer to monitor red light runners from the downstream side of the signal, so as not to have to run through the red light to stop a violator. They only come on when the red light on that arm is on.

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