How average speed cameras work?

[Andy_Pagin]

Picked this from an article in the Bucks Herald

[Albigularis]

Depends on the system. Some are front facing, some are rear facing and some new ones can do both lanes.
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Biking history so far-
Aprilia RS125 - Kawasaki ZXR400 - Triumph Street Triple R - Suzuki GSXR1000 L3 - BMW R1200GS - Kawasaki Z1000 - Kawasaki ZX10R C1H - Ducati Multistrada 1200 S Touring - Suzuki Hayabusa

[Vracktal]

Average speed cameras are basically OCR (optical character recognition) devices staged at timed intervals down a road. They trigger once they read a number plate and record the time taken to travel a the set distance between each camera. If the time taken is below the set time it would take for a vehicle to travel the set distance (plus a small margin of error), then it determines a speeding offence has taken place.

This is why I find it wholeheartedly amusing when people spank it down the motorway between average speed cameras, then jam on the brakes down to the limit at each gantry.

It used to be the cameras were fairly simplistic and could be easily fooled. In the early days, each camera was assigned a specific lane only, so to evade them you only had to change lanes. Now the entire gantry is networked so each camera set covers both lanes.

As well as that, they used to only face forward as this allowed them to capture the face of the driver as well. Now, because of motorbikes (probably) they face rearward in some sections, or alternate between frontward and rearward.

They're also equipped with infrared now so they can better read characters at night (which is why the sensors have that glowing red hue at night.)

Despite all these upgrades though, they still have vulnerabilities. The way they're programmed is to only recognise certain fonts and character strings based on license plates in the UK (i.e. they only read the UK number plate font to avoid false captures from things like logos and letterwriting on trucks and vans).

I think the syntax they're programmed for is something like "any string in [licence plate font] where max characters = 7". This means if you're using plates in a nonstandard font like the curly italics ones, the sensor might not always trigger*. Similarly, I don't think they can read euro plates at this time, and i'm still not sure if they can resolve three-line motorbike plates like the ones on old BMWs (which are legal if period-correct!). Additionally, I think they have trouble with small plates as well.

One day i'd love to dissect one of them and find it's operational specs. I'd be curious to know the processing power they have, and the maximum number of plates they can resolve between each gantry simultaneously. Purely for the sake of curiosity, of course...

*I am absolutely not willing to confirm any of this. YMMV.
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2007 BMW R1200R: On road
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[Andy_Pagin]

[ScaredyCat]

[iwaldo]

Maybe it's just me but I've yet to see any rear facing average speed cams in Scotland, hopefully this new set going in on the M8 is front facing too, in any case I just stick to the speed limit in case there is some sneaky hidden cam haha
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MT-09 / YZF600R Thundercat '02

[Kickstart]

[Alpineandy]

[Kickstart]

[Alpineandy]

[Kickstart]

Hi

Reflections, odd angles they are mounted at, shadows, shadows of mounting bolts, partially obscured plates (from other vehicles), etc. I suspect that the success rate of reading the plates is far less than they would like us to believe, but still high enough to screw over enough people to make them a pain.

Also wonder if having them ignore non UK plates makes them technically illegal by not treating drivers of different nationalities equally

All the best

Katy
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[techathy]

[Alpineandy]

[andyscooter]

[Kickstart]

[Silver_Fox]

I laugh in the face of forward facing average cameras on the motorways and pay no attention as I smash it through
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CG125

[Kickstart]

[Polarbear]

[Silver_Fox]

I was in a rush to get to the BCF Wales trip to meet some random men in a field
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CBR600 F3 FV
CG125

[mentalboy]

If it's good enough for James....

https://www.007james.com/i/gadgets/aston-martin-db5/revolving-number-plates.jpg
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Make mine a Corona.

[Aceslock]

[Mudshark]

[Silver_Fox]

[winz]

[Mudshark]

my reading is, an operator will review the images if the camera system detects an average speed above the limit in force.
(for front facing cameras the Blackbird will not even be detected)