How do average speed cameras work?

I read this first, but it still doesnt make sense http://www.speedcamerasuk.com/SPECS.htm

I can understand it for cars, but for bikes we don't have a front numberplate and the cameras seem front facing. The ones facing the other way are for the other carriageway?

The way the article makes it sound, is that bikes arn't affected by them. But if something sounds too good to be true then it probably is...

alot of average speed camera's around here are forward faing so dont get motorbikes, although they do turn them around so that they are rear facing now and then so you have to keep an eye out

[Viney]

As said, sometimes they are turned round so can catch bikes! As to how they work, they use ANPR (Automatic number plate recognition) and measure the time it take for the numberplate to travel between to fixed points. This is then converted into time and distance, therefore speed.

I see... so if they are facing the front of my bike when approaching them, they cannot catch me?
Also, this ANPR must surely be affected by smaller numberplates...

[Viney]

Thats a myth. The software is pretty good nowadays and probably will read many fonts and sizes. That said, there are probably a few fonts that i could think of that it would get wrong!

You are correct in your assumption, but remember that the avergae speed is there for a reason, and even on the bike, i 99% of the time abide by it!.

Originally Posted by Magnum

I see... so if they are facing the front of my bike when approaching them, they cannot catch me?
Also, this ANPR must surely be affected by smaller numberplates...

well they wont get your plate but some times they leave two forward facing and two rear facing therefore catching everyone.

Oh of course, i was planning on breaking it (especially on my bike...) but there will be times when its OK to go a little faster. As proved by the Benelli yesterday that overtook me at about 100mph...

well they dont flash lik normal camera's they record your number plate and you would get it sent through the post, so you would never know untill you recieve that lovely piece of paper that say "WAS IT WORTH IT" lol

Small collection of infrared LEDs + Digital Camera = Epic win.

Originally Posted by Magnum

Oh of course, i was planning on breaking it (especially on my bike...) but there will be times when its OK to go a little faster. As proved by the Benelli yesterday that overtook me at about 100mph...

Another bike breaking the speed limit proves nothing other than the rider is a c*ck.

A front facing camera will never catch a bike. However, an ANPR camera that cannot see a number plate will always ask a CCTV operator for their actions. So they could dispatch a patrol car out with an accurate description of the vehicle and rider.

As for the accuracy of ANPR, assuming you're travelling at 50mph+, they won't be able to read a 7x5 plate. It's simply too small.

However, there's a gate near me (ironically it's the automatic gate on the entrance to the local police station) that ANPR still thinks is a Renault Scenic with no tax or insurance.