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not_sure_i_care
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Joined: Apr 10, 2008
Posts: 23
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 Posted: Thu May 01, 2008 7:01 pm Post subject: |
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| Andy_P2002 wrote: | | Also, I maintain that there's no way a normal Gatso/Monitron etc. can "flash" at a different speed dependant on the vehicle type, |
GATSO cameras use the doppler effect to establish the speed of a vehicle, the return on the radar for say a car v's a van/lorry is different. The camera has a setting for two speed thresholds to allow it to enforce at two different speed settings depending on the return from the vehicle. TruVelo have a similar setting, however it cannot enforce the two different speeds automatically, it relies on a wire remote connected to the camera used by an operator to select the lower speed if a different class of vehicle approaches the sensor. Therefore not used very often unless at a manned semi-permanent site. |
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pcaouolte
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Joined: Dec 27, 2006
Posts: 998
Location: South Lincs, UK.
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| Posted: Thu May 01, 2008 7:57 pm Post subject: |
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| not_sure_i_care wrote: | | The camera has a setting for two speed thresholds to allow it to enforce at two different speed settings depending on the return from the vehicle. TruVelo have a similar setting, however it cannot enforce the two different speeds automatically, it relies on a wire remote connected to the camera used by an operator to select the lower speed if a different class of vehicle approaches the sensor. |
To quote the last part of Andy's post on page one of this thread
| Andy_P2002 wrote: | | ... I've seen no concrete proof of this. Anyone know THAT for sure? |
Have you any proof  |
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M8TJT
The Other Tired Old Man
Joined: Apr 04, 2006
Posts: 10118
Location: Bexhill, South Sussex, UK
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| Posted: Thu May 01, 2008 8:08 pm Post subject: |
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| not_sure_i_care wrote: |
GATSO cameras use the doppler effect to establish the speed of a vehicle, the return on the radar for say a car v's a van/lorry is different. |
Do GATSOs work on CW or pulsed doppler? I am fully aware of the theory of both pulse and CW doppler, but am at a loss to understand how the GATSOs can tell the difference between a car and a van. How is the returned signal different?
As far as I can see, this descrimination could possibly be based radar cross sectional area, which itself depends on the shape of the object (vehicle) and only partially dependant on its size, so is fraught with possible mis identifications. |
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not_sure_i_care
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| Posted: Thu May 01, 2008 9:02 pm Post subject: |
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| They use Continuous-wave radar, when you think about that amount of radar that is bounced back, the bigger the vehicle, the more there is. The cameras are calibrated to understand the difference between the return from a car and that from an HGV. Yes, it is subject to potential error, however as each image is viewed by a manual operator it is fairly easy to determine between a Mondeo and a DAF truck. |
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DennisN
Tired Old Man
Joined: Feb 27, 2006
Posts: 14892
Location: Keynsham
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| Posted: Thu May 01, 2008 9:54 pm Post subject: |
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| strumble wrote: | Obviously I can see that this thread is going nowhere.
However, over 700 visits have been made so perhaps my ‘reservations’ have been noted.
I would like to thank you for your postings and draw these points out of the 34 postings.
Perhaps, the topic can be locked? |
You are right, strumble, it's not a progressing debate any longer. There have been too many more senior participants than myself for me to take the step of locking the thread - perhaps someone from the Team will, please? I am worried that opinions seem to be getting set in concrete and on this site, that's not the way we usually go.
In the meantime, may I suggest it might take very little effort for a note to be made on the download page reflecting the basic fact that the database publishes car/bike-related data and there are other limits for other types of vehicles/driving situations - WITH A LINK to an article on the subject, which I suggest strumble could put forward - he's already contributed the main bulk of it.
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Dennis
If it tastes good - it's fattening.
Two of them are obesiting!! |
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Darren
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Location: Hampshire, UK
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| Posted: Thu May 01, 2008 9:57 pm Post subject: |
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I'll ensure a note is added to the download page before the next database release.
Thread locked.
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Darren Griffin |
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Darren
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Location: Hampshire, UK
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| Posted: Fri May 02, 2008 11:47 am Post subject: |
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I've hived these posts off from the orginal debate as they related to GATSO technology rather than the original discussion subject.
I've also mistakenly moved the above two posts which should have remained in situ so I have quoted them in the original debate to maintain continuity here.
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Darren Griffin |
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Andy_P
Pocket GPS Moderator
Joined: Jun 04, 2005
Posts: 19991
Location: West and Southwest London
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| Posted: Fri May 02, 2008 1:17 pm Post subject: |
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So, to summarise:
We've so far found two comments on websites that say that some or all Gatsos CAN differentiate between different vehicle types or sizes:
| Quote: | Gatso speed cameras can also identify between cars/vans and HGVs separately. For example, if the speed limit was 60mph for cars/vans and 40mph for HGVs the camera will enforce the two separate limits.
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(http://www.speedcamerasuk.com/Gatso.htm)
| Quote: | | Some Gatso's can also tell the difference between a car and HGV, so if for instance the limit was 60 mph for cars and for HGV's it was 40 mph, if HGV's pass the threshold of approx 45-50mph the camera would be triggered. |
(http://www.ukspeedcameras.co.uk/guide.htm#Gatso
Whether that is "Gatso" the brand or "Gatsos" generically, I don't know, and those two statements look so similar I wonder if one was the inspiration for the other?
I've still been unable to find any confirmation of this feature on any manufacturer's or official website. How about Monitrons, SPECS etc?
Maybe "not_sure_i_care" can point us to some more information? |
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Darren
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Location: Hampshire, UK
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| Posted: Fri May 02, 2008 1:54 pm Post subject: |
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I too would be interested to see some proof. I'm not doubting it is indeed so but I am surprised at the complete lack of any mention of this technology on any manufacturers web-site?
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MaFt
Pocket GPS Staff
Joined: Aug 31, 2005
Posts: 15138
Location: Bradford, West Yorkshire
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| Posted: Fri May 02, 2008 2:13 pm Post subject: |
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i'm sure alix has received an NIP for going over the "hgv speed" in a transit van? or is my memory playing up?
MaFt |
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not_sure_i_care
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| Posted: Sat May 03, 2008 7:54 am Post subject: |
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By GATSO, I mean a GATSO camera. I am not using the term GATSO to refer to all speed/safety cameras.
As I stated earlier, TruVelo cameras can do this but not automatically. I am unsure about SpeedCurb (used to be called Monitron as it was them that developed the technology to an extent but this was then spun out and RedSpeed was formed) Having said that without classification loops prior to the speed measurement sensors I am sure it would not be able to do it. SPECS, in theory, could do it but it dumps the offence if the speed is not over the required threshold. SPECS do not communicate with the DVLA at the roadside.
It is posible for say a box van to trigger a GATSO at a low speed, in these instances it is entirely down to the operator to establish that the offence is null and void. |
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Skippy
Pocket GPS Verifier
Joined: 24/06/2003 00:22:12
Posts: 2946
Location: Escaped to the Antipodies! 36.83°S 174.75°E
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| Posted: Sat May 03, 2008 1:28 pm Post subject: |
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| MaFt wrote: | | i'm sure alix has received an NIP for going over the "hgv speed" in a transit van? or is my memory playing up? |
I remember a story about someone being done for speeding in a tranny van when they were keeping up with all the other traffic (NSL). BUT this was a mobile unit NOT a fixed Gatso.
I remember hearing the rumour about Gatsos enforcing two different speeds but I've not seen any conclusive evidence (ie, a NIP). Maybe someone with a small truck would vounteer to test it? 
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Andy_P
Pocket GPS Moderator
Joined: Jun 04, 2005
Posts: 19991
Location: West and Southwest London
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| Posted: Mon May 05, 2008 7:03 pm Post subject: |
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| thanks for your second post "not sure I care". you sound like you know what you're talking about. Are you able to tell us where your info comes from? |
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Skippy
Pocket GPS Verifier
Joined: 24/06/2003 00:22:12
Posts: 2946
Location: Escaped to the Antipodies! 36.83°S 174.75°E
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| Posted: Mon May 05, 2008 11:28 pm Post subject: |
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According to Gatso's website:
| Gatso wrote: | | The radar 24 system can be set to distinguish between cars and lorries. |
Are these the same as the Gatsos we all know and love in the UK? Are they type approved to operate in this mode?
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not_sure_i_care
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Posts: 23
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| Posted: Wed May 07, 2008 7:27 pm Post subject: |
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The Type-24+AUS Gatso is the camera / Radar measurement device is the device used in the UK. TruVelo use the Combi-SMC system.
So in answer to the question, yes it is the same one. |
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