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.

A recent Cochrane review examining 35 studies investigating the effect of speed cameras on speed and collisions concluded that although the quality of the studies was moderate at best, the consistency of all studies to report a positive reduction in either speed or collisions was impressive

That's 35 for and one against, due to heavily manipulating no less than 5 different variables, in order to force themselves to have to conclude that speed cameras don't improve safety.

Read your links folks!

Boy, I can just feel the salt from a past speeding ticket coming from this comment.

Maybe stop being a shitty driver who feels entitled to break traffic laws designed to keep people safe from entitled, careless idiots in their two-tonne metal box. 💀 You're whining elsewhere in the thread about a 37 in a 35 (3.2 km/h over, which should actually be taken seriously by law enforcement but isn't because of a culture of entitled drivers), so you're not even complaining about accuracy so much as how much illegal driving you think you should be able to get away with. Speed limits are already across the board much higher than they should be to cater to cars; if you don't feel like you're competent enough to do something as trivial as stay exactly the speed limit when they're already unfairly high in your favor, then it's a limit for a reason: you can go a mph or two slower than it, and you won't, like, die or anything.

No. This is a safety thing. This is multiple tons moving at speed. This gets regulated.

I don't think anyone has ever received a speeding fine from a speed camera who was going at the speed limit.

Stop being a cunt and think of others road safety.

Oh I have. I used to ride motorcycles and there's no better way to feel out those roads, I've been off-road too.

But the reality is it is the main form of transportation and it is not optional for most Americans. Which means we have a duty to make it as safe as possible. Yeah that also means boring. We've largely let capitalism and personal preference rule the day and motor vehicle accidents are the largest non-disease cause of death because of it.

And before anyone gets all up in arms about the every day person knowing a ton of regulations, this should all be taken care of on the manufacturer and seller side of things. The size requirements for commercial licenses should come right down to invalidating future purchases of giant pickup trucks, you know the ones, so big they can't park properly and an M1A2 tank has better visibility. Speed governors should prevent going over 80mph. Headlights should have a max capacity and a thermal camera should be standard to make night driving clear as day.

But the biggest thing by far is we need to make a project of mass transit such that driving becomes a profession and a hobby, not the main means of transportation. If we can get commuters and road trippers off the road then motor vehicle accident deaths will fall dramatically.

The statistic here isn't accidents. It's fatalities in accidents at X speed. Germans aren't driving cars that are any safer than the rest of Europe. If they get into an accident at 70mph or higher then their chance of death is also sharply increased.

The big difference between German roads and American ones is Germans can generally opt out by taking a train. Americans cannot.