Thirty five studies met the inclusion criteria. Compared with controls, the relative reduction in average speed ranged from 1% to 15% and the reduction in proportion of vehicles speeding ranged from 14% to 65%. In the vicinity of camera sites, the pre/post reductions ranged from 8% to 49% for all crashes and 11% to 44% for fatal and serious injury crashes. Compared with controls, the relative improvement in pre/post injury crash proportions ranged from 8% to 50%.

Authors' conclusions: 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.

Edit 2: That being said, speed cams are objectively helpful aren't the sole tool we should be using. Traffic calming is enormously beneficial and cost-effective for making places with roads safer for drivers and pedestrians.

[–] empireOfLove2@lemmy.dbzer0.com 24 points 1 month ago (35 children)

Is it the cars, or is it police using laws as revenue generators that intentionally affect the poor disproportionately?

[–] TheTechnician27@lemmy.world 28 points 1 month ago* (last edited 1 month ago) (13 children)

Would it generate revenue if people didn't feel so entitled to put others' lives in greater jeopardy to get to their destination 30 seconds faster? No? Not speeding is the easiest thing in the world; it's an objective number not to exceed that you directly control and that your car tells you in real time, but at least in the US, drivers are in an arms race to see what kind of bullshit they can get away with, making cops less likely to pull them over. This means that when the average driver can – without warning and with precision – be dinged for speeding, they throw a tantrum about it and act like they've been victimized.

Ticketing does disproportionately affect the poor, and we should reform ticketing to change based on income, but can you seriously tell me with a straight face that the people doing this are doing it because they're protesting socioeconomic injustice? Or because they're entitled drivers who want to be able to speed with impunity? It's the drivers here being entitled and thinking that they're above the law. Personal vehicles are a privilege, not a right, but drivers don't treat it like one. Over 100 people per day die to motor vehicle crashes in the US alone, and kinetic energy increases with the square of velocity; if drivers don't like speed limits, they're more than welcome to stay off the streets and stop thinking their personal convenience trumps people's right to life.

[–] Jarvis2323@programming.dev 6 points 1 month ago (2 children)

These cameras do nothing to improve safety. There is no meaningful scientific evidence that shows any difference improvement in safety.

Their only value is socioeconomic harm.

“after accounting for MVC increases in the control segment we found that neither camera placement nor removal had an independent impact on MVCs. In other words, speed cameras did not statistically contribute to an increase or decrease in the number of MVC.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3861844/#:~:text=after%20accounting%20for%20mvc%20increases%20in%20the%20control%20segment%20we%20found%20that%20neither%20camera%20placement%20nor%20removal%20had%20an%20independent%20impact%20on%20mvcs.%20in%20other%20words%2C%20speed%20cameras%20did%20not%20statistically%20contribute%20to%20an%20increase%20or%20decrease%20in%20the%20number%20of%20mvc.

[–] TheTechnician27@lemmy.world 24 points 1 month ago* (last edited 1 month ago) (1 children)

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.

[–] Jarvis2323@programming.dev -3 points 1 month ago (1 children)

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.

[–] TheTechnician27@lemmy.world 9 points 1 month ago (1 children)

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.

[–] Jarvis2323@programming.dev -4 points 1 month ago (2 children)

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.

[–] then_three_more@lemmy.world 10 points 1 month ago (1 children)

So you're going to go back on the death (and injury) part now that it has been pointed out that the study you linked was only about the collisions. And itself points research that shows that there is a reduction in death (and injury).

Right?

[–] TheTechnician27@lemmy.world 3 points 1 month ago

LotR "no" meme

[–] TheTechnician27@lemmy.world 10 points 1 month ago

The authors of the systematic review had no reservations in asserting that the cameras lowered injuries and deaths, so how do they not affect safety? Do the cameras emit cancer-causing 5G beams or something that bring the number of injuries and deaths back into equillibrium?

[–] undergroundoverground@lemmy.world 24 points 1 month ago

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!

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