Fixed speed cameras
This report evaluates all of the fixed (Gatso-type) speed cameras across the whole of the Thames Valley area.
This is the second report world-wide to have results that do not include RTM.
Report: “THE EFFECT OF FIXED SPEED CAMERAS ON ROAD SAFETY“
Quick summary:
The graph shows the collision rate at all of the fixed speed camera sites in Thames Valley.
We can see that there were fewer collisions after cameras than before.
But if we look more closely, we can see that the entire reduction had already occurred 6 months before the cameras were installed.
Speed cameras cannot travel back in time and prevent collisions when they weren’t there, so what could have caused the reduction 6 months before?
The answer is RTM (Regression to the mean).
The selection of these sites was influenced by the higher than normal collision rate during the SSP (in green). At the end of the SSP, the collision rate returned to normal and it took 6 months before the cameras were installed (in blue).
After installation, collisions continued at around their normal rate, much the same as would have occurred without the cameras.
- The entire reduction in collisions was due to RTM, with the speed cameras having produced no benefit whatsoever.
- Fatal and serious collisions increased after speed cameras were installed.
SpeedCameraReport.co.uk 