The city of Columbia will be putting up red light cameras soon. However, they are not up yet.
And yet, there are cameras at a whole bunch of intersections in Columbia. What are those?
They are traffic signal cameras.
First off, they are not part of the city of Columbia. Although they are located in the city, they are on state-maintained roads and have been placed there by MODOT’s district 5 traffic division.
They are cameras in the sense that they do visually inspect the intersection. They help trigger the light to switch between red/green/yellow. Essentially, they increase and descrease they amount of time a light stays green based on traffic levels. They are a lower-cost replacement for the wire induction coils that they formerly buried under the streets.
The video from the cameras are not sent anywhere. Instead the cameras process the image inside the camera and then send a simple yes/no signal for traffic lanes to the traffic light controller.
MoDOT apparently has been asked about it often enough to put up a FAQ: http://www.modot.mo.gov/stlouis/links/signalcameras.htm
So, the ultimate question: do these cameras violate privacy?
The answer is mixed:
They don’t, as currently used, violate privacy in any way. They don’t send video or images anywhere nor is anything recorded.
But, they do help get us comfortable with cameras at intersections. And, they are cameras. So they could one day be retrofitted to a new purpose.
This isn’t a conspiracy theory per se. I do believe that MODOT’s motive was simply to save money. Given the downsides of the induction loop method they once used, it makes sense.
But, I can’t help but worry about the long term implications.

