# Reliability/Accuracy of Garda Laser Speed Guns



## roker (23 Feb 2013)

Interesting article in todays news on speed cameras

http://www.dailymail.co.uk/news/article-365563/The-great-speed-gun-scandal.html


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## mandelbrot (23 Feb 2013)

Is that gun ( LTI 20.20) in use in Ireland?


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## JohnJay (24 Feb 2013)

if its in the Daily Mail, it MUST be true....


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## britvic55 (24 Feb 2013)

Interesting article, most motorists just pay the on the spot fine rather that fight it in court. and rarely do they enquire as to the current make and model of lazer gun being employed by gardai in ireland, and to see the current calibration cert of the gun in question was it the (lazer gun) correctly calibrated on day of incident etc ? if the daily article is correct  then there are many many lazer guns in use that could not possible be properly calibrated ? interesting info for a solicitor fighting someones case in this respect ?


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## ajapale (24 Feb 2013)

from wikipedia:



> In 2005 a BBC program Inside Out  demonstrated how the LiDAR speed gun most commonly used in the UK, the  LTI 20.20 could create exaggerated reading.
> 
> Errors came from two  sources.
> 
> ...


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## roker (24 Feb 2013)

I do not think the model of gun is relevant; it is the principle and use of a flawed system.
As a retired calibration Eng, I asked for details of the gun used when I got done for 6 mph over, and was refused details.


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## ajapale (25 Feb 2013)

roker said:


> I do not think the model of gun is relevant.





roker said:


> Interesting article in todays news on speed cameras
> 
> http://www.dailymail.co.uk/news/article-365563/The-great-speed-gun-scandal.html




But the Daily Mail article in your original post specifically refers to one specific model of laser gun - LTI 20.20.


The Daily Mail story appears to date from 2005.


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## Time (25 Feb 2013)

They stopped using the LTI 20-20 years ago. The use a gun called an ultralyte.


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## britvic55 (25 Feb 2013)

but surely Roker being a retired calibration eng, you are aware that speed lazer guns used by gardai are actually sent to germany for calibration ? this may have now changed since 2011 ? with reference to being allowed refuse you to see the calibration cert they are within their rights to do so, but if it goes to court and you ask the judge if they can supply said cert normally he / she will oblige and  tell gardai supply the cert  as evidence, ...also if stopped by gardai on speed gun duty and they insist you are over the speed limit you can request to see the speed and ask for the lazer gun serial number..this ensures if you later go to court and ask the judge to see the calibration cert..the one they produce in court is the actual cert for the gun in question , as they all carry an individual serial no. therefore a seperate calibration cert is required for each individual gun,  which carries the date and time of calibration...


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## Time (25 Feb 2013)

Under Irish law they have no obligation to show you anything. They don't have to prove it was working properly. It is up to you to prove it wasn't.


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## roker (25 Feb 2013)

Good point Britvic55, they could be doing lots of people with out of date calibrations, maybe they should be using ISO 9000 etc and be audited. I did mistakenly look at the date on the top of the Daily Mail page, which is todays date


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## alexandra123 (25 Feb 2013)

> Under Irish law they have no obligation to show you anything. They don't  have to prove it was working properly. It is up to you to prove it  wasn't.



Where is this in law ? As it does not make sense that they dont have to prove it.


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## Time (25 Feb 2013)

It makes no sense but it is the law.

http://www.oireachtas.ie/documents/bills28/acts/2004/a4404.pdf
Page 12


> It is not necessary to prove that the electronic or other
> apparatus was accurate or in good working order.


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## ajapale (25 Feb 2013)

from : www.radarlaser.com.au

The *LTI                                        Ultralyte* evolved                                        from the original 1991 Laser                                        Speed Gun - the LTI 20-20.                                        The Ultralyte was the first                                        model to operate on batteries                                        (C-cells) in the unit rather                                        than from an external battery                                        pack or lighter socket.

                                      Like all Laser Speed Guns,                                        the LTI must be held very                                        steady to obtain a speed reading.                                        This is why a speed reading                                        often takes much longer than                                        a second after the trigger                                        is pulled.

                                      The Ultralyte is now used                                        in Queensland, Western Australia,                                        Tasmania, South Australia,                                        the Australian Capitol Territory                                        and the Northern Territory.

*Advantages and limitations of Laser Speed Guns:* 

The                                  narrow beam (less than 1 meter at 300                                  meter from the laser gun) makes target                                    identification more certain than radar                                    under some conditions.
Detection                                  by Laser Detectors is very difficult.
Halogen                                  car headlights and driving lights reduce                                  the range of the Laser Speed Guns.
Refraction                                  errors can produce incorrect speed readings.                                  Because light is refracted differently                                  by hot air than cooler air, a spot of                                  air rising from the roadway can confuse                                  the laser.
Laser                                  beams can be affected by atmospheric conditions.                                  Speed reading range is reduced on cloudy                                  or foggy days.
When                                  the laser beam bounces off more than one                                  solid object (stationary or moving) reflection                                  errors occur, producing an incorrect speed                                  reading.


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## roker (25 Feb 2013)

If It is not necessary to prove that the electronic or other apparatus was accurate or in good working order. Why bother maintaining it at all? just use a dummy gun and guess a mph reading


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## Time (25 Feb 2013)

In theory there is nothing to stop them from doing so.


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## ajapale (22 Mar 2013)

This very old Daily Mail report has been recycled again to day.


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