Speed cameras: Are we interested in evidence?

[Dave Finney]

heebeegeetee said:

Dave Finney said:

Well, sometimes.
The very last example at the bottom. That was a dual carriageway, wasn't it?
https://speedcamerareport.co.uk/effects-of-speed-c...

I am struggling Dave. I notice you don't date your reports. I notice that the report you're referring to '4YE' is now 20 years old, studying the years 1999-2004.
Isn't this all completely out of date?

My reports are dated. Each report has 3 pages:

Overview
Main report (date published at the top)
References

The 4YE is old, but it remains to this day the largest report on speed cameras in Britain.

The reason all these reports are old, is that they've stopped publishing the data.
Even the data they did publish, they've removed.
And they've NEVER run scientific trials,
nowhere in the world have they ever run scientific trials!

[Dave Finney]

heebeegeetee said:

Dave Finney said:

My reports are dated. Each report has 3 pages:

Overview
Main report (date published at the top)
References

The 4YE is old, but it remains to this day the largest report on speed cameras in Britain.

The reason all these reports are old, is that they've stopped publishing the data.
Even the data they did publish, they've removed.
And they've NEVER run scientific trials,
nowhere in the world have they ever run scientific trials!

It's me then, I can't see the dates. https://speedcamerareport.co.uk/scientific-trials/

Sorry,
Only my 3 reports using the data from the Thames Valley database are dated.

The other pages are just for information.
Eg the speeding page is data collected when I made the website.
I've edited the page every now and then, but not updated the data.

It's not my job you know.
I don't get paid for any of this.
I provide the evidence because I managed to do what all the experts were paid to do, tried to do, and failed.
And I felt it was my public duty to inform others so that lives could be saved.

[Dave Finney]

Cat said:

That's really weak reasoning for why the reports have not been cited by others. In the years since you produced the reports there have been dozens, if not hundreds, of studies by academics into speed cameras and their effects on collision rates and severities. To suggest that none have cited your reports, that are apparently "the most accurate ever produced", because the conclusions are not politically acceptable is not credible.

Well some reports are using the methods that I developed, and not a single one has credited me.
They are also using some of the terms that I invented,
so I am making a difference, even if it's small and slowly.

Can you find a single one of your possibly hundreds of speed camera studies,
that has removed the effect of site selection?
(a clue: they call it “regression to the mean”, or RTM or RTTM).

[Dave Finney]

Cat said:

Dave Finney said:

Can you find a single one of your possibly hundreds of speed camera studies,
that has removed the effect of site selection?
(a clue: they call it “regression to the mean”, or RTM or RTTM).

They are not my speed camera studies, but a quick Google brings up this as pretty much the 1st result which refers to 2 studies that address RTM...

There are several reports that "address" RTM, but none of them "remove the effect of site selection (RTM)".

Your link is: https://road-safety.transport.ec.europa.eu/eu-road...
BTW, the links for both of the reports are broken.

Neither of those reports removed the effect of site selection.
One of them "controlled" for RTM and the other "corrected" for RTM.
What that means is that they both estimated what effect RTM might have had and, from that, estimated what effect the cameras might have had.

My report does NOT use estimates of RTM,
it simply removes the effect of site selection (RTM) directly, without any estimates.
and finds the effect the cameras directly.
That's as accurate as you can get (without running scientific trials).

Furthermore, you can see it for yourself in the graphs, both in my reports and in my video.
https://www.youtube.com/watch?v=-GqOm-keyss

Thank you for trying, want to have another go?
Can you find a single one of your possibly hundreds of speed camera studies,
that has removed the effect of site selection (IOW without making estimates)?

[Dave Finney]

nute said:

Dave Finney said:

I have provided the highest quality evidence possible, given the data available.
https://www.youtube.com/watch?v=-GqOm-keyss

Thank you for that, very informative and I appreciate the time and effort which has gone into it.

Thanks nute,
I find the research relatively easy, but presenting the results is much more difficult.

It's nice to get confirmation that my video might explain the evidence in a way that most people can understand.
Thanks again.

[Dave Finney]

Cat said:

So if your method removes the effects of site selection/RTM, an issue which studies acknowledge needs addressing, and makes reports the most accurate ever, why after over 10 years have your reports never been cited in any other research? Why, if your methodolgy is as good as you say, has your method not been universally adopted by all researchers working in this area?

My new methods and terminology are being used/misused but I'm not being credited and my reports are not cited.
I think I know why but I'm not saying here.

When I first presented my research, my target audience was road safety professionals.
After speaking with hundreds of people working in and around the area of road safety,
I came to realise that they were not interested in evidence,
because road safety is not safety engineering,
it's politics dressed up to look like safety engineering.

So I changed tak.
My target audience now is the general public.
I massively cut down my website, removing a lot of the detail, to make it easier to read,
(except the 3 reports on the TV database, they are unchanged)
and produced the video.

I am asking you, Cat, please think for yourself.
There's a limit to what I can do to help you.
I say I have "completely removed the effect of site selection".

What do YOU think?
Watch my video, read the report.
https://www.youtube.com/watch?v=-GqOm-keyss
https://speedcamerareport.co.uk/08_mobile_report/

Do you understand what the SSP is, and how to identify it in the data?
And do you understand why using the data outside the SSP does establish what the collision rate would have been without the cameras?
And that this works without using estimates?
https://speedcamerareport.co.uk/rtm-regression-to-...

Have I demonstrated to your satisfaction that what I say is true?

[Dave Finney]

heebeegeetee said:

Not to me unfortunately.

I started this topic because I'd made a video and wanted to know
have I explained the SSP, how to establish the "mean" rate and, therefore, what effect the cameras have,
well enough that someone who is not a road safety expert can understand it?

I am generally very pleased with the response to the video,
it's better than anything I'd tried before.

Even if I haven't explained that well enough for you,
you must surely be able to see that the big collision reduction at the camera sites,
(the reduction that the officials suggested was due to the cameras)
had already occurred a full year BEFORE the cameras started operating?

The cameras cannot go back in time,
so it is physically impossible for the cameras to have caused that reduction.

You must at least be able to see that?

[Dave Finney]

heebeegeetee said:

I expect there to be rules, I expect there to be enforcement, I don't think there's enough enforcement.

I'm not persuaded the cameras are causing more problems than they're solving. I always think, as motorists we could decide to just follow the rules of the road, I honestly don't think that would be a great hardship, and I think would actually make our lives immeasurably easier.

We just then need UK policy to not be 50 years out of date, and if we could just stop people crashing unnecessarily so much, life would be much easier.

I can't believe you reject evidence for every issue.
It seems likely you reject evidence either for

1) road safety (speed cameras, why crashes occur etc) and maybe some other select topics
or
2) anything that challenges the official narrative.

I also agree that we should "not be 50 years out of date".
My solution to that is to start using an evidence-led approach,
and that then ensures that our policies actually achieve their stated aims.

And the gold standard in evidence is scientific trials.
https://speedcamerareport.co.uk/scientific-trials/

[Dave Finney]

jm doc said:

Dave Finney said:

nute said:

Dave Finney said:

I have provided the highest quality evidence possible, given the data available.
https://www.youtube.com/watch?v=-GqOm-keyss

Thank you for that, very informative and I appreciate the time and effort which has gone into it.

Thanks nute,
I find the research relatively easy, but presenting the results is much more difficult.

It's nice to get confirmation that my video might explain the evidence in a way that most people can understand.
Thanks again.

Yes Dave, great posts and great thread, well done and keep going!

Thanks for your support jm doc,
I am finding it very interesting seeing what people think of evidence,
especially when it clashes with long held opinions or the authority narrative.

Before researching road safety, I had never really discussed evidence outside work, and certainly never with officials.
I've since heard all sorts of opinions but I never expected people to just reject evidence outright in an area of public safety,
especially by those in charge of policy!

I can see why the authorities carried on saying the earth was at the centre of the universe,
even after Galileo provided the evidence that they were wrong!
They and others still seem to have the same mindset to this day!

[Dave Finney]

heebeegeetee said:

I think all you've proven is a very low number of complete incompetents have crashed their cars at specific locations.
The numbers are very low indeed and it's a an aspect of road safety that affects such a low number of people that I challenge you to express it as a percentage.
That's it Dave, that's all you've proven.

It's s one hell of a stretch to be comparing it to the known universe.

I agree with you that the evidence "proves beyond a reasonable doubt",
that the use of speed cameras
has resulted in more people being killed or seriously injured.

You're asking: "how many more, as a % of the whole TV area?"
In my report, Table 8.4 shows an increase of 23 KSI in 13 collisions over the first 3 years.
That's against around 1200 KSI pa over the whole TV area.

So that's an increase of less than 1% (about 0.6%),
and the changes in KSI each year in the whole area were always greater in magnitude than the yearly average increase at the camera sites.
So you can see how the damage caused gets hidden amongst all the other factors.

So again, I agree with you.
The numbers are low, but it is still 3 more people dead each year.

[Dave Finney]

vonhosen said:

I don't think that's his point. so much (the figures).
I think the point is an illustration of the methodology & call for a science based approached on that methodology.
I'm just not sure that it will result in what he wants, because it isn't as narrow a consideration as that when it comes to speed limits & their enforcement.

You've got it spot on, vonhosen.
Road safety officials don't understand the system they're working on,
and that means more people seriously injured on our roads.
https://www.youtube.com/watch?v=-GqOm-keyss

All my research really does, is point out that there is a problem,
and the problem is not speed cameras per se,
it's that the theories that support road safety policy are fundamentally flawed.

[Dave Finney]

vonhosen said:

But road safety policy isn't removed from politics & isn't likely to be. Because enforcement, particularly with speed limits, doesn't exist solely on road safety grounds. Sure It's a consideration within a wider policy, but it's just one part of it.

Yes, I agree.
If scientific trials were run,
other political considerations could also be incorporated into the trials (as well as road safety),
and the benefits (or otherwise) of each included factor would be proven.

[Dave Finney]

andrebar said:

If I’m understanding it correctly the research points to suboptimal use of the cameras rather than a fundamentally flawed strategy. Or in other words more serious injuries could be prevented by making better use of the evidence available. Which is not the same thing as claiming that more injuries occur because the cameras are being used.

Possibly.
The evidence does suggest that "more injuries occur because the cameras are being used".
IOW, if the cameras had not been used, there would have been fewer fatal and serious crashes.

You're right, this does point to "suboptimal use of the cameras",
IOW, there may be ways that cameras can be used that at least don't result in more fatal and serious crashes,
and could maybe even reduce them.

But that will never happen until the authorities recognise that there is a problem,
hence my video: https://www.youtube.com/watch?v=-GqOm-keyss

[Dave Finney]

vonhosen said:

You mean like hiding/disguising them so that drivers can't see them or know their locations?
Be careful what you wish for.

Again, vonhosen, I agree that that is 1 possible solution to the problem.
But there are issues.
1) You're making the same fundamental error that the authorities are making,
. . You've jumped to conclusions, and are simply proposing policy based on opinions.
. . that's what got us into this mess in the 1st place!

2) It has been tried to some degree.
. . The 1st cameras were painted grey and often hidden behind signs, bridges and trees
. . and there were no camera apps to warn you either
. . The evidence shows an increase in fatal and serious crashes at those sites:
. . https://speedcamerareport.co.uk/09_fixed

We need to know who, when and why there are more fatal and serious crashes at the camera sites.
Until we have that, we cannot know what might solve the problem, without risking even more death and injury.

[Dave Finney]

heebeegeetee said:

1. Such as hide the cameras?

2. Which I doubt any of us here on PH would ever want, and would possibly be very unpopular with the public?

Possibly, but you have asked the question that I was asking in the title!
"Do the public support policies based on evidence?"

Suppose the public were told:
We are going to run hidden speed cameras in certain areas for 3 years within scientific trials.

If death and serious injuries are proven to be reduced, we may continue that policy.

But if death and serious injuries are proven to increase,
cameras will never be hidden again,
and ALL cameras will be required by law to be run within scientific trials.

Would the great British public support policies that are based on high-quality evidence?

[Dave Finney]

vonhosen said:

If research shows that people behave like stupids when they see cameras (sudden emergency braking, or our wheelie motorcyclists) resulting in fatalities, then that is because they saw the camera & reacted adversely to it.

The research only shows that there are increases, it does not show who or why..

You're still jumping to the conclusion that it is only "stupids" crashing at camera sites,
but it could be that otherwise safe and responsible people are also increasing the crash rate at camera sites.

Eg;
there is 1 FSC* every 3 years at camera sites**.
also around 8% of FSC involve a vehicle speeding***.

So cameras might be able to prevent 1 FSC every 37 years,
but, during that time, they may be changing the behaviour of most (nearly all?) drivers/riders,
even those who are not and would not have been speeding.

So the cameras may be resulting an extremely small increase in crash risk but multiplied by an extremely large number of drivers/riders,
to prevent an extremely small number of crashes involving speeding.

(* fatal or serious collision, ** on average in the TV database, *** exceeding the speed limit).

[Dave Finney]

heebeegeetee said:

One question from an above link, re "higher than normal collision rate during the SSP" - has that occurred at every site?

I do like questions about the evidence/data (thank you) but I don't know the answer for those Fixed camera sites.
Your quote is from this quick summary: https://speedcamerareport.co.uk/09_fixed/

The raw data is on my website, so you could work it out for yourself.
If I find time, maybe I could do that for you?

For the mobile sites, some were NOT selected after a high collision rate during the SSP,
In fact, 12 of the sites had no collisions at all in the SSP.
Fairly obviously, collision numbers could only go one way (up) and they did.
There were 14 collisions in the first 3 years of mobile speed camera operations at these 12 sites.

[Dave Finney]

heebeegeetee said:

Thanks. How long does the SSP take, usually?

The SSP is the period of time when collisions influence the choice of where to place cameras.
The SSP is not a set period, different officials chose different SSPs, but they tend to be around 3 years now.

In the early days, fixed cameras were installed by the local councils and they used an SSP of 5 years.
In TV the cameras took at least 6 months to install, and there were delays with some sites of up to a further 6 months.
So the SSP for the group of fixed cameras was 5.5 years.

Much later, almost all mobile camera sites were chosen by the new partnership and they used a 2.5 year SSP.
With no delays, the SSP for the group of mobiles was that 2.5 years,
and this can clearly be seen in the graphs in the video and report.
https://www.youtube.com/watch?v=-GqOm-keyss

[Dave Finney]

YorkshireStu said:

Mandat said:

That wouldn't be a problem if speed limits remained at or near the natural safe speed for a particular road.

The cameras are not only fine as they are, we need more and the entire country to be subject to an average-speed system with automatic fines and permanent bans zero exceptions in place.

May I ask why?
Is it your perception that speed cameras actually do save lives?
Remember the speed camera partnerships were told "Public perception must be actively managed".

Suppose speed cameras are leading to more deaths,
how many people dead every year would you tolerate and still support their current operations?

I propose something which to me is obvious, yet seems radical to many,
Let's PROVE what effect speed cameras are having by running them within scientific trials!

[Dave Finney]

New average speed cameras in Manchester,
and they are using an RAC report using my FTP method to:
1. claim they will save lives, and
2. refuse to run a scientific trial.

The cameras: https://news.tfgm.com/press-releases/3e9a126d-b617...
The RAC report: https://www.racfoundation.org/wp-content/uploads/2...