Safe Speed Forums

A new Truvelo forward facing camera has sprung up on the A62 between Manchester and Oldham which I use each day on my way to work.

It's a 30mph limit dual carriageway on which the normal speed is around 40mph (quite safe).

Does anybody on this forum know how the Truvelo works. On the road in front of the camera there are three thin white lines across the full width of the road. The lines are very close together. The markings are nothing like those used for Gatso cameras.

Thanks
Jim

They are sensors which tell when the car's going over them, and the sensors are linked to the camera. If it detects that you've travelled from one sensor to the next in too short a time to be within the speed limit, it takes a picture of you. Other than that, not sure.. Only ever seen one in my life, and it gave me a fright as I was doing about 75 (on a DC) at the time!

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-mike[F]
Caught in the rush of the crowd, lost in a wall of sound..

Yeah, it doesn't use radar like a Gatso, it just times how long it takes the car to travel over the three lines.

Nasty devices, Truvelos -- at least with a Gatso you get plenty of time to check your speed after seeing it, whereas often with a Truvelo by the time you've spotted it, it's often too late.

Also be aware that since Truvelos are essentially passive conventional detectors don't pick them up, though GPS systems will still warn you. I've read somewhere that some laser detectors can pick up the flash (which is infrared) of another vehicle getting zapped, but I doubt it's more than theory. Even if the detector can pick it up in real situations, which I doubt, you'd have to rely on a car ahead of you setting the thing off at the same time as you approach it. Not likely. Oh, and since it's infrared, you don't know you've been zapped until the NIP turns up. If you're a biker there's some good news. They photograph the front of vehicles, and bikes don't have front numberplates

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Make everything as simple as possible, but not simpler - Einstein

Thanks for the replies so far.

From what Mike (F) is saying, I guess the camera would only take one photograph of an "offending" car, the evidence of speeding being provided by the three sensors in the road.

If this is so, what implications are there for requesting and checking the evidence if one is sent a NIP? The photograph would prove nothing surely.

Jim

Well presumably the timestamps can be overlaid on the photograph in much a similar way to how they are on gatso photos. I mean, the only way the gatso photos can be used as evidence of speeding is with a time being associated with each photograph. So I guess there isn't a problem with doing the same thing with a truvelo photo - and the distance between the sensors will also be preset into the device, I presume.

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-mike[F]
Caught in the rush of the crowd, lost in a wall of sound..

What mike[F] says makes sense, and if that's the case then the photo is probably just to identify the vehicle. BTW, does anyone know why it's three sensors? Is it so that the time to get between the 2nd and 3rd is a check against the time between the 1st and 2nd, and if the difference is too large the system assumes a faulty reading and so doesn't take the photo?

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Make everything as simple as possible, but not simpler - Einstein

beware the Truvelo on the same road a bit closer to manchester (near the halfway house pub and TMS in failsworth) - it is in the mcr->oldham direction and is sneakily positioned just as you come round a corner. There is a gatso on the other side of the road heading towards manchester so one is forward facing and one is rear facing which I bet has caught a few people out.

I think that must be it. With three sensors, you can get three readings of speed (1-2, 2-3, and 1-3), and I guess they would all need to agree with each other.

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-mike[F]
Caught in the rush of the crowd, lost in a wall of sound..

The information on the Truvelo site (http://www.truvelouk.com/speedmeasurement.phtml) seems to contradict the comments above. According to this, there are two pairs of independent sensors, and then 1.8m further down the road are the 3 white lines (whos purpose is illustrated on this page).

I'm guessing, based on this, that the system calculates two speeds, one from each sensor pair, and if they match (allowing for any feasible change in speed of the vehicle as it passes between the two pairs) then that's the speed the system compares against the preset threshold. It's not clear then how it triggers the camera such that the front wheel is over the white lines - I'd have thought it would use a separate sensor buried under the middle white line, but it could also use the measured speed and known distance between the sensors and lines to determine how long after the first sensor reading is taken before the photo should be taken.

Chris

Interesting links, Twister. It seems that the white lines are for backup, just like the markings are on Gatsos. I was going to ask what white lines as the Truvelos I know don't have any, but by the sounds of things they're not absolutely necessary. Or they might be something new - I haven't passed one in neraly two years. Course, the paint might have been all scrubbed off by people hitting the anchors
By the looks of the photo on the Truvelo site I'd guess it's a timing thing rather than another sensor under the white lines. The shiny black lines showing where the sensors are buried run all the way to the edge of the road, presumably so they run to the camera or a control box. Nothing like it coming out from under the white lines, and as I said, I'm sure the few I used to pass regularly didn't have any anyway. Presumably they still worked.
The real eye-opener on the Truvelo site is that some of the damn things can work in either direction. I thought that you only had to worry about Truvelos on the same side of the road as you're driving, but it seems Mr Plod can turn the bugger round to point at traffic coming the other way. That's something else to distract us from the business of driving, checking Truvelos on the other side of the road to see if the lens side is pointing our way. Do they actually want us to watch the bloody road anymore?

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Make everything as simple as possible, but not simpler - Einstein

D'oh, maybe next time I'll research something rather than guessing?

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-mike[F]
Caught in the rush of the crowd, lost in a wall of sound..

Thanks for replies so far. I'm asking about this one because this is an example of a camera that you have to slow down for, because the speed limit is absurdly low for the road, so (almost) everyone travels at a sensible speed that is 10mph above the limit. And no - they are not all dangerous drivers!

So the real issue with the Truvelo is that you don't know when it is measuring your speed. Cue bunching and unpredictable braking - now that's what "safety" cameras are for!

There's one of these on the A56 near the fire station at Higher Broughton, Manchester. As you're travelling northwards, it's on the other side of the road, pointing at you.

Having said that, I believe there are a few examples of offside Gatsos too.

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"Show me someone who says that they have never exceeded a speed limit, and I'll show you a liar, or a menace." (Austin Williams - Director, Transport Research Group)

Any views expressed in this post are personal opinions and may not represent the views of Safe Speed

Yes, I'm sure had the work been done ten years earlier, the improved A62 dual carriageway between Oldham Way and the M60 (about 1½ miles) would have been given a 40 limit. I drove down there earlier tonight at about an indicated 40 and was being regularly overtaken by carloads of yoofs.

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"Show me someone who says that they have never exceeded a speed limit, and I'll show you a liar, or a menace." (Austin Williams - Director, Transport Research Group)

Any views expressed in this post are personal opinions and may not represent the views of Safe Speed

If it had been done more recently, I'm sure the limit would have been set lower, not higher. I doubt there's been a single speed limit raised nationwide in the last ten years...

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-mike[F]
Caught in the rush of the crowd, lost in a wall of sound..

Er ... a very minor instance, but the B4102 between Solihull and Catherine-de-Barnes was indeed raised from 30mph to 40mph within the last 18 months. Not much, I know, but still, a small straw to clutch at.

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Keep right on to the end of the road ...

I don't think it would have been set any lower - 30 is quite low enough for a major dual carriageway running through an area where most of the houses have been knocked down. The point was that many similar roads still have 40 limits.

There have been a handful of speed limit increases, but all the ones I can think of are where the limit on a short non built up section has been raised from 30 to 40 to allow the installation of prominent 30 gateways at either end when entering a built up area. An example of this is on the B6234 between Stanhill and Knuzden Brook near Blackburn.

See:

http://speedlimit.dreamwater.org/images/speedup.jpg

This did actually happen, and in LanCA$Hire too.

The speed limit on the M4 bus lane section was also raised from 50 to 60 mph, but that is a case of two steps back, one step forward.

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"Show me someone who says that they have never exceeded a speed limit, and I'll show you a liar, or a menace." (Austin Williams - Director, Transport Research Group)

Any views expressed in this post are personal opinions and may not represent the views of Safe Speed

interestingly, I drove past the one on the A62 (the one at the top of this thread) yesterday and noticed it had been decapitated