How can one recognize the “defendant” on the camera photo in 2 vehicles?

Hello municipality, today on a two-lane road in the inner town a police or ambulance bus coming from behind with blue light and Martinshorn made room, whereby I changed from the left to the right lane and stopped there at the roadside or rolled at maximum step speed. Unfortunately I was now exactly in the detection area of a well-known, stationary speed camera. I still thought “ha, it will catch it now fully” and ZAPP!!! – it flashed. And only then came to me in the head that I could be in the photo now, because I was perhaps 2 car lengths in front of the staring box. How should someone in this situation possibly prove that not he.. but just the operating vehicle on the left track was too fast? I assume that an induction loop has sunk on each lane. Had to drive again long to be sure. Does the speed camera register, because of which triggered loop it flashed? So much excitement. So what is nothing for my a It’s the heart.