Temporary speed cameras

[Dr Lobster*]

there has been some 'bridge strengthening works' going on down a stretch of the a47 which i sadly have to cross to get to work - it's been going on for a few months and whilst the works were going on about six 'specs' speed cameras were installed, although they were removed overnight yesterday and no trace of them ever being there exists.



these cameras, as you probably know work by taking timestamped photographs of your car and then working out your average speed by calculating how long it takes you to get from the first camera to the second.

but i am not completely convinced these temporary cameras functioned. not much information is published about how these cameras actually work - there was clearly no cable running between them so i can't see how they could be reliably synchronised - surely a pre-requisite if you're perform a time critical calculation?

does anybody 'in the know' know how these cameras are synchronised? it was the lack of visible cables running between cameras sites which made me suspicious that they were just there for show.

[cdd]

Maybe they just get the time from a trusted time server? I don't see why they need to be synchronised to each other, only to a correct (well, not correct so much as constant) time source.

[Ebeneezer Scrooge]

...or maybe using GPS for time sync - I assume they must be fairly geo-aware anyway for the system to work, so a frame accurate clock would be a handy by-product.

If that's not how they work, does anyone fancy going into business? I've got a great idea for a GPS based speed trap system!

[marksi]

GPS would provide them with timestamps.

Oh. Like what he said.

I've noticed that on the stretch of road home that benefitted from the SPECS cameras over about 6 miles, the traffic is increasing its speed back up to near what it was before, which suggests they are set well above the actual speed limit.

[Sput]

I'd have thought the easiest solution was using the cellular network to get times and just ensure the distance between the cameras is known. No point in making it fancier than it needs to be.

[cdd]

Go on Sput, you're a scientist: let's have a plausible explanation that'll hold up in a court of law for how we travelled from Camera A to Camera B without speeding!

[Stuart*]

Go on Sput, you're a scientist

That's wrong, apparently, so is praising Mr Q's financial acumen.
Tsk at you (by Gav's rules)

[barcode]

Those cameras have been on the A77 for about 4 years now around Prestwick section, There have been able to help cut the accidents rate, and help slow down traffic .

[Stuart*]

Those cameras have been on the A77 for about 4 years now around Prestwick section, There have been able to help cut the accidents rate, and help slow down traffic .

the 'universal translater' said " $%"! "

[cdd]

i have become confused by your posts stuart. Should i interpret them as ironic, sarcastic, matter-of-fact, bitchy, bitter, sour grapes or just general weird aimless shoot-anywhere ranting?

[Sput]

Go on Sput, you're a scientist: let's have a plausible explanation that'll hold up in a court of law for how we travelled from Camera A to Camera B without speeding!

Well it's simple really, all you have to do is travel from camera A to camera B without exceeding the speed limit.

You didn't put a time limit on the journey