kittycat1

How do they work?

If I've sat in a queue and then floored I'll be ok as long as my average is within the speed limit? no?

rowell

They measure time taken to travel between cameras and determine average speed, hence if you are stood still for a while presumably this is not counted, so you can join the locals and floor your accelerator, let us know if it doesn't work

jam25mack

It's the time between 2 points so you can chill 50 below the limit for a bit and then drive it like you stole it for the remainder as long as you ensure you are above the minimum time.

Why where have they put average speed cameras?

Bahtatboy

Yes, you'll be ok.

When the new bollard-type cameras were installed on the SZR I heard that they were enabled to measure average speed. There are two requirements for a system to measure average speed: cameras with sufficient resolution to capture registration numbers, and the hardware/software capable of transmitting, storing and analysing the data. I don't know if the installed cameras have sufficient resolution (but they probably have); hardware would require cabling between the cameras and back to a control centre, which is almost certainly in place, and the software is an easy add-on. It all, of course, should have been installed and enabled from day one...

seven seas

You're safe if they install two cameras: one at each end.

If they install several cameras along your route, your average speed can be measured for the entire route as well as for small sections.

kittycat1

This was in the uk on my way to the airport this morning - m25

jam25mack

Mmmmm, UK! They can be bastardos! The trick which used to work for some of them (the ones where the cameras are overhead on the gantry) was to make sure you change lanes. I.e don't come out of the road works in the same lane as the one you went in on. Apparently the cameras were linked one to one and not group to group.

scrubbedexpat141

Changing lane theory - wasn't that just myth?

Bahtatboy

Yep.