Average Speed Cams?

Originally Posted by -Ralph-

Don't take this as gospel...

Actually, you can almost take this as gospel, the manufacturers website gives the same, if less detailed description

http://www.speedcheck.co.uk/specs.htm

[I]"The video cameras continuously capture images of vehicles as they pass through the field of view of the camera. Their number plates are read using Automatic Number Plate Recognition (ANPR) and the average speed of the vehicle is calculated between the linked cameras, over the known baseline distance. If this exceeds the Police speed threshold, an offence record is created and violation images and data are logged."/I]

[Drew Carey]

Just to add, the cameras on the opposite side of the carriageway CANNOT get you. They are calibrated to work on one side only and to focus at the three / two lanes on that side.

Like Ralph said, I think it is a bit of an urban myth that they use them to track you and catch up later, as it is an ANPR based system only.

http://www.speedcamerasuk.com/SPECS.htm

Originally Posted by Drew Carey

as it is an ANPR based system only

Which is why the police have got so ar$ey about non standard number plates recently. You'd think so long as it's legible, what does it matter, but it's so big brother can watch us with technology.

[Drew Carey]

You would have thought be now they could create computers that can not only write different fonts but read them too?

Originally Posted by Drew Carey

You would have thought be now they could create computers that can not only write different fonts but read them too?

They can, but they all have some margin of error and you'd end up with the occasional ticket being sent to the wrong registered keeper. BA03 DOC in italics could end up being read as 8403 00G

[Stu]

Originally Posted by -Ralph-

Don't take this as gospel...

As far as I understand it, the cameras work in a minimum set of two. They record your reg plate using APNR, then record a video image, and overlay this image with that info and a date and time stamp. When you pass the second camera it records a second image with another date and time stamp, and again using your reg plate on APNR, marry this up with the first image. It then calculates your speed using the date and times recorded vs the distance between the cameras. Only if that speed is above a certain threshold set for recording an offence, does it save the images, otherwise it discards them.

Therefore I believe that if it doesn't have your reg plate to do an APNR on, the computer can't marry up the two images, therefore cannot do a time/distance calculation, and therefore doesn't "save" any images recorded. I'm not even sure if it records the first image if an APNR fails.

Just my 2p, happy to be stood corrected, these things are so surrounded by myth, but this is what the most reliable sources I have read have said about them.

I think guys that have been caught by repetitively speeding through cameras, based upon bike, gear, etc have been speeding through Truvelo or forward facing Gatso

Thanks, saves me typing exactly my same thoughts.

Originally Posted by Gabriel2k

Is it really worth the risk and uncertainty? Just slow down and safe yourself the worry.

But average speed cameras can cover a huge stretch that I'd prefer to ride as I see fit.

The worse thing about the cameras on the motorway sections is that they are there to "protect" the workforce...

Even on sunday at 4 in the morning when theres been nobody there since friday night.

nope they dont, wel the ones on the M4 near bath dont as i went through them at a ton a few weeks ago

[Red Herring]

Originally Posted by neio79

nope they dont, wel the ones on the M4 near bath dont as i went through them at a ton a few weeks ago

That's OK mate, plenty of other ways of sorting you out given the inclination.

Originally Posted by speedplay

The worse thing about the cameras on the motorway sections is that they are there to "protect" the workforce...

Even on sunday at 4 in the morning when theres been nobody there since friday night.

Frustrating when that's the case, but they won't know when they start a set of roadworks whether it will require weekend and night shifts. It depends on how far behind schedule they get due to c*ck-ups, weather, etc.

It's also to mitigate against narrower lanes, stray traffic cones, adverse cambers, lane switches or contraflows, etc.

I have some sympathy with why the restrictions are there, I've hit a stray traffic cone at speed on a pitch black windy M74 many years ago. My father hit it in a Vauxhall Carlton, it popped out of his rear bumper then I hit it in a Vauxhall Cavalier, 2 1/2 grand damage to the Carton which left the motorway on a recovery truck, about half that to the Cavailer, which left on a towing dolly behind the recovery truck. Needless to say my father's employer that owned both cars wasn't best pleased.