Your own study links to a Cochrane systematic review which states the following:
Despite the methodological limitations and the variability in degree of signal to noise effect, the consistency of reported reductions in speed and crash outcomes across all studies show that speed cameras are a worthwhile intervention for reducing the number of road traffic injuries and deaths. However, whilst the the evidence base clearly demonstrates a positive direction in the effect, an overall magnitude of this effect is currently not deducible due to heterogeneity and lack of methodological rigour. More studies of a scientifically rigorous and homogenous nature are necessary, to provide the answer to the magnitude of effect.
You linked a study that took place along a single 26-mile stretch of road in Arizona, and while it does some good toward controlling for confounding variables, a single, highly localized study simply isn’t as robust as a Cochrane systematic review.
Moreover, the study you link focuses on the number of collisions, while the Cochrane review focuses on injuries and deaths. What we were talking about before was – say it with me – injuries and deaths because of entitled, speeding drivers.
It focused on the Arizona study because that was the only one out of the 35 that actually measured Motor Vehicle Collisions. The rest did not even attempt it in any controlled manner.
As stated, there are no meaningful studies that these cameras reduce accidents.
So it sounds to me like you’re not disputing the fact that they have a protective effect against injury and death. Maybe you should clarify that in your prior comment if that’s how you feel.
I am in fact stating that there is no proof that they do anything to reduce collusions or deaths. I stated in my first comment that such proof does not exist.
These cameras are only deployed to generate revenue. There is no scientific basis for improved safety.
