I didn’t realize they did this until the person posted on Piggington way back. It got me thinking about it.
When they installed the cameras in Del Mar, it took them 3 days just to calibrate one intersection for running the red light straight through the intersection. The cameras they used in Del Mar do not use a coil, they just rely on the images and map areas on the picture where someone ran the light.
My guess is that the camera itself isn’t smart enough to detect a rolling right turn on red, so at the intersections where this is common, a cop just reviews the video.
I did a right turn on Red after a full stop in downtown where they have one of those signs that says no right turn between 9 and 11 and 2 and 3 and 5 and 7, and of course a camera. Didn’t read the sign before I went through. It was between 2 and 3 and I didn’t get a ticket, so it lends credence to the idea that this isn’t automated.