Safe Speed Forums

Hope this is of interest, in reply to my question about conducting a properly scientific test of gatso effictiveness with a control group of Garden Gnomes:

If you cut and paste the link below, you may find this information by Napier University useful, as it deals with some of the issues you have raised concerning speed and cameras.

http://www.rospa.com/road/congress2002/ ... adling.pdf

I doubt that you would find any road safety professional agree to your experiment with garden gnomes as it would show a blatant disregard for human life. We spend a great deal of time analysing collision patterns to see where a camera can be most beneficial - it is not a random science. To "test" a location in this way and gambling with a strong likelihood that people could be killed and seriously injured would be irresponsible at best.

Many thanks for your interest

Safe Speed for Life Admin


And my reply:

But that is just it. The point is that you have no conclusive proof that speed cameras have saved even a single life, and until you undertake a proper scientific test using a control group (garden gnomes or parsnips, doesn’t matter) as any drug testing procedure would do, you never will. For all you know from the statistics you have, all accident reductions you attribute to speed cameras could be explained by the well known statistical phenomenon of regression to the mean. Perhaps this from Professor Stone, emeritus professor of statistics, University College London, would explain better

http://www.ucl.ac.uk/Stats/research/Resrprts/speed.pdf

Perhaps it is you that is showing a blatant disregard for human life by not investigating seriously and scientifically the true effectiveness of speed cameras, and thereby risking missing other potentially more important factors.

Thank you in anticipation

Richard Bryant

They must have figures from sites/roads/areas that they monitor to see if it requires a camera based on the KSI's from the last 3 years. So whats wrong with giving us the figures for these sites that don't quite have the required KSI's to justify a camera.

Yes that would be a good start, but would still produce biased figures, as anything closer to the average would tend to show less of a reduction than the extremes do they select. Best way, select the 1000 worst sites and use half as a control group, measure over next 12 months and compare.

I just love the simplistic justification in the first table. Basically you are 50% more likely to have been involved in an accident if you have been caught speeding.

Any statement like that is totally with out merit without due consideration for miles travelled, ergo what are the possibilities that having a speeding conviction may be more likely if you drive more than average milage and less likely if you drive less than average milage as indeed I would say is the possibility that you may have had an accident.

Could this "fact" not have more to do with miles travelled?

Yes, its just sloppy thinking, there could equally well be a third factor causing both

eg

when I eat chocolate I get acne
Therefore chocolate causes ache

Not necessarily - both could be caused by stress.

Any competent scientist could devise a test to measure the true effect, but the speed camera partnerships seem strangely unwilling to contemplate this on the grounds that they already know the answer.

How could speed cameras fail then Ker-ching!

_________________
DO NOT PANIC

Aren't the ones that get caught speeding possibly the dozy people though? A lot of people that get caught by a fixed gatso are in the dozy category so it could actually be true that those people are more likely to have an accident. People that choose to speed even though they accept the risk of penalties could have a differing personality type which makes them more prone to accidents which is nothing to do with whether they speed or not. Reps and businessmen rushing around spring to mind. They'll be much more likely to take risks while driving than somone pootling around with all the time in the world. Those that speed regularly and don't get caught would be a much more interesting group to study. Compare them with the don't speed at all types and see whether there is a difference in accident risk between them.

Talk about simplistic, that report isn't worth the paper it's written on!

I've never received a speeding ticket, yet nowadays I seem to be constantly in fear of speed cameras when driving (despite the fact that I keep to the limits in built up areas), to the point where I'm very concerned about how much time I spend watching my speedo. Does this make me a safer driver? According to the scamera partnership, of course it does.

Me thinks this could have a lot to do with a p[ossibility that the great unwashed are more likely to be in stolen and unregistered vehicles ahen the buzz around the grey and satanic mills.

Bloody hell this report really is a joke but I'll bet itprovided "significant" funding to the university