Actually, it was ShangahiBill who attempted to move the goalposts. My original response was to his claim that " It isn't clear if yellow light duration was decreased in the intersections studied." It's clear.
Even then it was just some interesting questions he raised. Probably not known until he goes through the Paywall.
Not very likely that a consensus can be reached, because what are the metrics? Some might say increased safety is laees accidents, some may say loss of life, some may say insurance company payouts. Some may just want the ticket money.
If you use less accidents as a metric, it is very difficult to defend the cameras. If less T-Bone accidents, you can. Money? Oh frabjous day, this is a friggin cash cow!
And safety? Hey, Washington will give you a redlight ticket if you don't come to a full and complete stop and turn right.
What is more, remember that the companies have a say, they love that money too. So some contracts specifiy the shortest yellow duration to maximize the number of people fined.
There's plenty more.
Now as ShanghaiBill noted, the real increases in Safety come from longer yellow light times. Very short times tend to cause more in the intersection accidents, and coupled with cameras, are more likely to produce rear end accidents, especially with the very short yellow light timing - and some say the photos are taken while the light is still yellow. I know myself, if we had redlight cameras in my area and short times. If I see the yellow light, I'm standing on the brakes. Yeah, I might get rear ended, but it will be the other drivers fault. I might know I am going to get hit, but I'll avoid a big fine. What a stupid, stupid system, that in essence causes people to purposely cause traffic accidents. That's just insane.
In principle, I hae no issue with redlight cams. In real life however, politicians are too anxious to get any non-tax revenue they can, and the companies that install and run these things are the kinfolk of the for profit prison people, so the demands for increased profits every quarter will have a similar effect. More tickets will need to be issued, and company pressure placed on the local Government to increase fines in order to increase profit. So there will be tinkering, I suspect in the end to just randomly take photos,of cars in intersections because most people will just cough up the thousand dollars or so it will cost by that time rather than hire a lawyer. Sweet gig if you can get it.
Since the human factor is inevitably and fatally flawed, the cameras need to be banned outright.