Re: Gatso said to be inaccurate...
 

I don't know about the accuracy of Gatsos, but before you all assume he is right, bear in mind that the guy who did the research is under threat of a speeding conviction. Therefore, he was probably looking for ways to prove himself innocent. It's also worth bearing in mind the timer he used may have been incorrectly calibrated.

Also, how many Gatsos did he drive past? If he drove past 10 and was flashed by 8 of them, he could conclude 80% are wrong. However, he could drive past another 90, not get caught and suddenly that 80% would become 8%

Interestingly, according to the cornwall police site I link to below, his timings are well within the limits for the camera. The delay between photos is typically anywhere between 500ms and 700ms.

Also, I found an interesting article on how Gatsos work at http://www.devon-cornwall.police.uk/...tech/gatso.htm OK, I know it's the police, but it does match up with what I read on another site (ukspeedcameras.com) which was selling detectors..

Re: Gatso said to be inaccurate...
 

All a Gatso does is take a photo. It doesn't stop you from speeding, it's your own desire to not end up with points on your license which controls that.

I'd call it the lesser of 2 evils but speed bumps get my vote, particularly attractive is the prospect of them causing boy racers to slow down lest they mangle the underside of their lowered vehicles.

Re: Gatso said to be inaccurate...
 

Ask the Highway Maintenance engineers round here who are constantly having to fill in the holes in the roads left after idiots have gone over speed bumps too fast and grounded out on the other side... :dozey:

Re: Gatso said to be inaccurate...
 

He isn't the only person questioning the accurcy of speed cameras:

http://www.theage.com.au/articles/20...?oneclick=true

http://rds.yahoo.com/S=2766679/K=vic...4/s1121730.htm

Re: Gatso said to be inaccurate...
 

If you drove a large vehicle for a living (pcv/lgv) you would not say that.
The constant shock from going over these is causing major back problems for a large number of drivers.

Re: Gatso said to be inaccurate...
 

This might go someway to explain why I've been flashed 4 times* over the last year going into Colchester. there are 2 cameras and I'm a good by so its 30 mph as soon as I get into the zone (and not just where the cameras are) but even then I've been flashed 4 times (one time I was only doing 25 according to my Speedo).

If what this guy says is true then there is a major issues because the prosecution is based on the assumption that the 2 photos were taken 500 ms apart. If this is not the case then the cameras at the very least need recalibrating. If the police are being good about this then they should look at the speeding convictions from that camera and refund those that are likely to be due to duff calibration.**

oh and the reason that there is no real response from the police etc. is because they were already approached by the gent in question and he got no response. I also suspect that as a policy, the police et al. will not comment on upcoming cases.

Scarlett.

* Before anyone asks, I still have a clean license no points whatsoever.
** On the other hand, this is the governments big 'we are doing something good' policy so _that's_ likely to happen!.

Re: Gatso said to be inaccurate...
 

It appears Gatso's are the Judge Dredd of speed enforcement - fully automated policing, jury, and executioner all in one.


I disagree - if a camera is found to be giving false evidence then ALL tickets should be refunded and points cancelled from the day the camera was installed and the camera should be replaced or removed.

Re: Gatso said to be inaccurate...
 

There is, of course, nothing to stop hundreds of like-minded people going out with calibrated devices and measuring their local cameras. The problem with a cover-up in this case is that you can't cover up the camera (well, you can, I suppose, but it rather defeats the object). I'm sure Escapee would know how to build a 1/100th second optical timing device.

Speed bumps I hate - they damage cars let alone spines and cause noise nuisance to people living next to them. Narrower roads or chicanes or raised areas that you can drive over perfectly well at 30mph but are uncomfortable faster than that have the same effect of making it easy for you to keep to the limit.

Re: Gatso said to be inaccurate...
 

It is actually quite easy to calibrate with an oscilloscope that can trigger reliably on TV Line syncs, It could also be done with a counter timer locked to Droitwich 198KHz off air standard.

I would personally use x amount of 64uS TV lines from a demodulated off air anaologue TV transmitter to calibrate a timer to use for comparison. This would be more than accurate enough, it would then be a case of using the gatso flash to trip a monosatble set for the 500ms. This could compare the monosatble with the gatso falsh used to trigger it.

He is an engineer, so it's likely he also has access to this sort of equipment.

Re: Gatso said to be inaccurate...
 

Yeah....... that's just what I was going to say.... :)

Re: Gatso said to be inaccurate...
 

My point was that I don't think he set out to test IF Gatso's are accurate. I think he set out to prove they weren't. I do realise he probably had access to equipment that could have been used to calibrate his timer (wether he did or not is another matter).

Re: Gatso said to be inaccurate...
 

We have just been discussing this one in work this morning, one of the guys here suggested a remote flasher used for photography could probably be used to trigger a pulse to be read on the oscilloscope. It wouldn't matter about the delay it took for the trigger, because it would be the same for both flashes, the only point to be sure about would be the recovery time between triggers.

I think this system could be set up and calibrated using a counter timer locked to the national off-air frequency standard 198KHz. It would be spot on accurate and there are many engineers in a similar position to myself who would have access to the equipment. I see no reason why his measuring method couldn't be as accurate as the company who manufacture it.
If it's locked to the off-air reference when in use, there could be no arguments about it's acuracy as its a national tracable NCAS standard.

very interesting :D

Re: Gatso said to be inaccurate...
 

At last a post from you which I feel makes sense. The council around here have made these modifications to some of the roads here and they certainly seem to have some affect but do not unfortunately do much to slow down the boy racers who usually seem to have small enough cars to comfortably go through them at speed.

Re: Gatso said to be inaccurate...
 

But the point is that he was still speeding, so of course he will not succeed.

I'm in favour of those speed sensitive signs that light up if you're going too fast either in 30 zones or at accident black spots. They have been shown to be more effective at reducing speed and accidents.

Everyone slips over the speed limit from time to time, these signs are a gentle reality check that most people will respond to.

This is a separate issue to the guy who's trying it on. You're saying that the trigger is set too low or inaccurate. He's saying that the gap between photos is too long, which would exaggerate the offender's speed on the pictures.

Of course it might well be your speedo that's wrong, but you should let your local police service know that you have a concern about a specific camera.

I've heard that some people are using these to 'blind' Gatsos. As an part-time photographer I have a couple of these little units for fill-in flash, the sense when your main flashgun fires. Apparently some people are using them in the back window of their cars so that when the Gatso flashes them, this gizmo flashes back.

I don't know if it works, I'd be surprised given the distance, but I would say that anyone doing so needs beating - I wouldn't want to be driving behind a car that was setting off flashes in my face.

Re: Gatso said to be inaccurate...
 

My bad - I didn't explain myself. If he was indeed speeding (and it appears he was) then yes he will be appropriately punished, and a good thing too. What I feel he will not succeed in however is having a review of the way Gatso machines work. This would have huge implications and as that site suggests, everyone who has been caught by one in the past could have their case reviewed and there just isn't enough time or manpower available to make that worthwhile, certainly not for a subject as speeding.