Safe Speed Forums

Can someone advise on the following:

I understand GATSO cameras are able to detect HGV's by the use of dopple radar and have 2 trigger limits and are set for cars and HGVs ?

With Truvelo's, are these able to differentiate by vehicle class ?

Reason for asking is that I hired a van this week and neglected to find out the different speed limits. Therefore I drove a 3.5t van at up to 70mph on a dual carriageway when it should be 60.
I passed some truvelo's, but would have slowed down to circa 65mph as I do in my car - would they have picked up the different limit ? Also would this trigger limit be set to 60mph +10% + 2mph, which means that I would be safe anyway ?

I also passed GATSO's but these were at 50mph limits on single carriageways and I was not exceeding the limit.

Anybody know anything about this to confirm ?

Pretty sure not.

See any flashes?

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Not that I saw !

Not that I saw, but then again, I'd normally be checking my speedo as I go past them so might not have noticed a Truvelo 'flash'.

Gatsos detect different lengths of vehicle. Truvelos (well, road sensor based devices) could possibly detect a different distance between axels. I don't ever remember hearing that they can. It is not mentioned on their web site and would be a good selling point.

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Andrew.

I've twice heard an unsubstantiated rumour that some Truvelos are accompanied with induction loops to get an indication of the metallic mass/size of the vehicle. I’ve never seen an induction loop at a Truvelo site.

The thing is, even if the site had an induction loop, at 3.5t it would not be able to distinguish between a large car / 4x4 / pickup or a van. The HC only states a reduced limit (extremely ill-defined IMO) for goods vehicles, so unless the camera had some kind of 'smart identification' system where it could look at the vehicle and say 'hey, thats a van' it would not be able to apply a reduced limit for this class and weight of vehicle.

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Science won over religion when they started installing lightning rods on churches.

Apart from wasted film, there's nothing to stop the camera taking the shot regardless (or at least having an educated guess), thereby placing the onus of differentiation of vehicle class on (for example) the operator processing the film/prosecution.

A trusty PePiPoo member found this:
http://www.roadtraffic-technology.com/c ... /truvelo2/
Thankfully, there's no mention of the 'Weigh in Motion' equipment being used in conjunction with a speed camera.

Steady on there - the only risk associated with an error in the detector is wasted film. It it triggers at the lower threshold optimistically - even flashing 2 ton cars - there's a photo to check against registration class before prosecution starts.

edit: SNAP! (but I lost )

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Cheers for all the advice people.

Interestingly, I searched the forums and found 2 instances of light goods vehicles were 'flashed' via Gatso's where they were exceeding the HC limit for vans.

One was doing 65 where the limit was 50 for vans (presumeably single carriageway that would be 60 for cars ?)

Also, the other one was for doing 68 on a dual carriageway where the limit was 60, 70 for cars. In this example, surely this was within ACPO guidelines i.e 10% + 2mph ??

Anyway it just shows that these NIPs are few and faw between as if there are only 2 examples here, and none involve Truvelos !

I regularly drive a 3.5t van , like to get along a bit but am a tad respectful near cams. However on the odd occasion that i have gone past one close to posted limit -nothing -only time was a faulty gatso flashing into my face.

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lets bring sanity back to speed limits.
Drivers are like donkeys -they respond best to a carrot, not a stick .Road safety experts are like Asses - best kept covered up ,or sat on

And you're assuming Paul (and smeggy) that the operator actually LOOKS at the photo and doesn't just send the NIP out regardlessl. (but I do see your point though )

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Science won over religion when they started installing lightning rods on churches.

IIRC All Truvelos have inductive loops. There will usually be some square patches in the road before the 3 white lines. That's where they bury the things.

Well, actually they have to look at the photo enough to grab the number plate - then software fills in the details, including name and address and vehicle registration class. So the software should trap any error and issue a NIP that states which law is alleged to have been broken.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Truvelos always use piezo pressure sensors for speed measurement.
Induction loops so close together will not be anywhere near accurate enough to determine the position (hence speed) of a vehicle.
[before anyone argues; perhaps induction loops could be used for precision position measurements (offset error only - no relative distance error), but the extrapolated corroboration measurement (which is absolute) will fail]
The ignition from the engine is also likely to affect the reading from an induction loop. Furthermore, the sensors are not actually arranged as loops



http://www.truvelouk.com/speedmeasurement.phtml

silly question but where are there gatsos and truvelos on nsl / duals or motorways, as this is the only time class of vehicle comes into play

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now retired

Or 50 limit single carageways or 60 limit dual carageways. (maybe I shouldn't have said that )

I've seen a few Gatsos on NSL single carageways. I seem to remember a couple in Somerset a few months ago. Not reflective either.
(there used to be one at the start of a three lane bit going up hill to catch the most people out but it's gone now yay)

I guess roads with lower limits are usually more profitable so...

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Andrew.

Warks is one ---a prize example is the gatso just before the A5/A444 junction - this one has been torched twice -
and Warks site mentions this as does the ABD site on Warks.

warks site


Looks like other areas are doing it too

_________________
lets bring sanity back to speed limits.
Drivers are like donkeys -they respond best to a carrot, not a stick .Road safety experts are like Asses - best kept covered up ,or sat on

The Truvellos in question are on the A43 between the M1 and M40 !

Dual Carriageway - NSL applies, but limit for 3.5 tonne vans is 60mph rather than 70mph.

Hope this helps !

Safety Cameras - Fixed Locations Back

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Your Location: Northants Police Online > Road Policing > Safety Camera Locations

Location Type Speed Limit
A14 - Kettering Junction 8 (Eastbound) Truvelo 70
A14 - Kettering Junction 9 (Westbound) Truvelo 70
A361 - Byfield Truvelo 30
A428 - Harlestone Road, Northampton Truvelo 40
A428 - Lower Harlestone Truvelo 30
A43 - Blisworth/Tiffield junc Truvelo 70
A43 - Geddington North Truvelo 30
A43 - Geddington South Truvelo 30
A43 - Green Man (NB) Truvelo 70
A43 - Green Man (SB) Truvelo 70
A43 - Lumbertubs Way Average speed 50