tru velo marked up as gatso!
Discussion
a query for you guys - they have installed 2 new truvelo scameras on a 30 zne near me - they are forward facing and have thesensors under the road - my query however is the markings
As you approach the camera you can see the scar on the road from the sensors and the three close white lines that cross the full ength of the carriagway for the calibratin - fine but....
as you contiue past the camera the road is marked with a set of standrda gatso markings - these markings are repeated and reversed on the other side.
Now to my mind the only reason i can think of for doing this is to make people think it is a gatso and rear facing when it isnt and blat through it - remember it is atru velo so no flash!
are these markings legal???
T
As you approach the camera you can see the scar on the road from the sensors and the three close white lines that cross the full ength of the carriagway for the calibratin - fine but....
as you contiue past the camera the road is marked with a set of standrda gatso markings - these markings are repeated and reversed on the other side.
Now to my mind the only reason i can think of for doing this is to make people think it is a gatso and rear facing when it isnt and blat through it - remember it is atru velo so no flash!
are these markings legal???
T
ASCII diagram (I hope)
Camera facing down
..... -
..... - GATSO markings (after camera)
..... -
..... -
[v] / Direction of travel
...========= Tru velo markings
..............-
..............-
..............- GATSO markings On other side of road
-
>> Edited by thewan on Saturday 19th February 19:55
Camera facing down
..... -
..... - GATSO markings (after camera)
..... -
..... -
[v] / Direction of travel
...========= Tru velo markings
..............-
..............-
..............- GATSO markings On other side of road
-
>> Edited by thewan on Saturday 19th February 19:55
A couple of points:
- Truvelos can be used in approaching and receding mode and also flipped around to face in either direction. Apparently they often switch them to catch motorbikes who think they can't be identified.
- Truvelos (and Gatsos) can also be used with or without Gatso-style lines, these just aid the calculation of speed. They can also measure the size of the car and manually calculate the speed if there aren't lines, but this takes much longer.
However I *think* there would need to be a piezo sensor at each place where a photo is taken - basically they can't measure the speed before the camera and take a photo afterwards, there would need to be piezo sensors there too.
Gareth
- Truvelos can be used in approaching and receding mode and also flipped around to face in either direction. Apparently they often switch them to catch motorbikes who think they can't be identified.
- Truvelos (and Gatsos) can also be used with or without Gatso-style lines, these just aid the calculation of speed. They can also measure the size of the car and manually calculate the speed if there aren't lines, but this takes much longer.
However I *think* there would need to be a piezo sensor at each place where a photo is taken - basically they can't measure the speed before the camera and take a photo afterwards, there would need to be piezo sensors there too.
Gareth
thewan said:Be thankful that you there are more 'warning' lines than usual. Camera operators/beneficiaries would prefer to have no markings on the road at all (as well as hiding the cameras).
Now to my mind the only reason i can think of for doing this is to make people think it is a gatso and rear facing when it isnt and blat through it - remember it is atru velo so no flash!
are these markings legal???
T
I'm sure there's no reason why Gatso markings can't also be used at Truvelo locations. AFterall, there are now many gatso type markings on roads where no cameras are sited - The White Stripes
Interesting website. Some quotes:
"Piezo-electric axle sensors allow speed measurement in tunnels, underpasses, close to bends and on bridges. No spurious speed readings possible"
That's good to know after so many spurious results from other types recently.
Hand-held version: "Speed range 20 - 180mph"
So we know how to handle that one then!
In roadworks: "Single photo per offence doubles capture rate per film. (and halves film & processing costs)"
So there's no chance of having 2 photos to verify the speed against those white lines then? So it's a good job that "no spurious speed readings [are] possible", as we're unable to challenge the reading anyway. A nice self-fulfilling prophecy:
Rule 1. Never an error
Rule 2. If you think you've been done, see rule 1.
"Piezo-electric axle sensors allow speed measurement in tunnels, underpasses, close to bends and on bridges. No spurious speed readings possible"
That's good to know after so many spurious results from other types recently.
Hand-held version: "Speed range 20 - 180mph"
So we know how to handle that one then!
In roadworks: "Single photo per offence doubles capture rate per film. (and halves film & processing costs)"
So there's no chance of having 2 photos to verify the speed against those white lines then? So it's a good job that "no spurious speed readings [are] possible", as we're unable to challenge the reading anyway. A nice self-fulfilling prophecy:
Rule 1. Never an error
Rule 2. If you think you've been done, see rule 1.
Peter Ward said:
So there's no chance of having 2 photos to verify the speed against those white lines then? So it's a good job that "no spurious speed readings [are] possible", as we're unable to challenge the reading anyway. A nice self-fulfilling prophecy:
To be far to them the system is different and only requires one photo. The photo confirms the wheels are on the white line. If they are they speed is correct.
Gatso needs to two photo's as you have no fixed reference point
bluepolarbear said:
So there's no chance of having 2 photos to verify the speed against those white lines then? So it's a good job that "no spurious speed readings [are] possible", as we're unable to challenge the reading anyway. A nice self-fulfilling prophecy:
To be far to them the system is different and only requires one photo. The photo confirms the wheels are on the white line. If they are they speed is correct.
Gatso needs to two photo's as you have no fixed reference point
Can you explain a little further? How is it that gatso's and other hand-held devices have been shown recently to produce errors, but you believe these are always correct? I understand that the wheels on the line are what trigger the reading, but surely at least some of the causes of error with other devices are applicable to this one too?
Peter Ward said:
Can you explain a little further? How is it that gatso's and other hand-held devices have been shown recently to produce errors, but you believe these are always correct? I understand that the wheels on the line are what trigger the reading, but surely at least some of the causes of error with other devices are applicable to this one too?
Truvelo works by measuring speed over a piezo electric strip burried in the road. (look up close you will see the black marks where the road has been dug up. After this point are three white lines painted close together. The distance between the line and the speed sensors is known. Therefore if you detect the speed of the vehicle you can calculating how many microseconds later the car will pass the three white lines. At precisely this time you take a photo.
If your orginal speed measurement was correct the photo will show the front wheels touching the middle of three lines. This confirms the speed measured was correct, if it doesn't then the measurement is wrong and the measurement should be discarded.
In theory you could have a scenerio where you are at the legal limit and the device over - reads your speed. It would however also have to have some problem with its timing circuitary and take longer than it should before taking the figure. The chances of two compound plus the fact that the second has to be of a precise time to snap your wheels on the white line is very small. More likely, the SCP don't bother checking the photo but just send the NIP anyway.
Morale of the story is always ask for the photo. I wasn't trying to say that a truvelo can not have errors just explain why you only need one photo to show its accurancy (beyond resonable doubt)
Gassing Station | Speed, Plod & the Law | Top of Page | What's New | My Stuff