Either they totally overestimated the speeding issue, or they underestimated the dissuasive effect of those cameras (which means they work actually pretty well... assuming they are correctly placed).
In both cases, a data set of vehicle speed at the site in the year before and after the cameras were introduced would be very useful.
Case 1: No change in traffic speed
Case 2: Dramatic reduction in traffic speed
Assuming they had that data set.
Case 1: would be kept as quiet as possible because it means the camera were either not needed for safety or not put in for safety.
Case 2: would be shouted from the rooftops (from both the local authority and the company running the scheme) because it would have shown a positive safety effect which is how these scheme are always sold as being a benefit to the community.