Oh No! Speed Trap

Originally Posted by laMon

just out of interest, what's the speed limit on that particular A road?
is it restricted to 40?

As it happens I know the stretch well (do it every day ) but I found it funny when reading his report as it kinda assumed EVERYONE did!! I'm_a_Newbie - the world is bigger than Portsmouth (thank god its a {insert expletive} hole)

Depending on what bit he is on about, it is either a 30 or 40 (it is 30 if it is nearer Portchester than North harbor). They normally sit in the 30 as there is a good hiding place and a 30 zone is a better nick than a 40

I just worry that if I do get caught, that's my licence gone It's too easy to make 'progress'

I never go silly in built up areas but some traps don't appear to be there for safety reasons and it's all too easy to drift above the legal limit, a couple of MPH above tolerance and your done. The local council traps seem to be more stringent than the police. I have used a road angel in my car for a number of years, does anyone have any sort of 'safety camera' device on their bike?

I get more paranoid about cameras on the opposite side of the rode getting the back of my plate!
I take it that ain possible, I assume they only read/work in 1 direction once they are set?

[the_lone_wolf]

Originally Posted by Hockeynut

I get more paranoid about cameras on the opposite side of the rode getting the back of my plate!
I take it that ain possible, I assume they only read/work in 1 direction once they are set?

i was under the impression that truvelo scameras work both front and rear facing but can only scan one lane of the carriageway, ie: the side it's mounted on

can't recommend trying it though, probably best to slow down briefly then return to cruising speed

Truvello cameras are activated by Piezo strips a few millimeters below the road surface. You can see the marks where they've been fitted (long straight bitumen lines about 30mm wide running at 90 degrees to the road) and on dual carriageways the strips are installed lane specific to avoid the confusion of multiple strikes from vehicles in both lanes at the same time.
There's usually a set before and after the camera so that it can be used forward or backward facing but obviously they have to rotate the head to do this and connect the other set of piezo strips.
Each tyre that runs over the strips is detected and since the strips are a set distance apart it is a simple distance/time calculation to measure the speed.

The cameras themselves, inside the housings, are obviously trained on a specific part of the road and nothing more, i.e. lanes 1 & 2 of one side of a dual-carriageway. I've not heard of them being used on single carriageways to catch traffic in both directions and I'm not sure it would be evidentially possible. I'll try to find out and update you all.

[the_lone_wolf]

Originally Posted by SV Muppet

Truvello cameras are activated by Piezo strips a few millimeters below the road surface. You can see the marks where they've been fitted (long straight bitumen lines about 30mm wide running at 90 degrees to the road) and on dual carriageways the strips are installed lane specific to avoid the confusion of multiple strikes from vehicles in both lanes at the same time.
There's usually a set before and after the camera so that it can be used forward or backward facing but obviously they have to rotate the head to do this and connect the other set of piezo strips.
Each tyre that runs over the strips is detected and since the strips are a set distance apart it is a simple distance/time calculation to measure the speed.

The cameras themselves, inside the housings, are obviously trained on a specific part of the road and nothing more, i.e. lanes 1 & 2 of one side of a dual-carriageway. I've not heard of them being used on single carriageways to catch traffic in both directions and I'm not sure it would be evidentially possible. I'll try to find out and update you all.

you sound like someone in the know, how did you aquire all this inside knowledge if i might be curious enough to ask?

the council here are pretty hopeless, they have installed truvelos with white painted strips on both directions of the carriageway, and occasionally come and turn the camera housing round.

Wow, nice reply muppet, thanks for the info!

Originally Posted by SV Muppet

I've not heard of them being used on single carriageways to catch traffic in both directions and I'm not sure it would be evidentially possible. I'll try to find out and update you all.

Aye, that's what I meant.

Here's another permiatation...How about if I'm overtaking, so I'm on the wrong side of a front facing camera which would read traffic going the other way? Ie, does it work in reverse? Yes I'm paranoid, and I also know the easy thing is not to do it. Just one of those things I've always wondered.

Just checked the Truvelo web site and I quote...

"Two-way operation possible from one nearside post with additional piezo sensors in opposite lane."

As I said it's best to look for the piezo strips in the road to know where it can detect from.
I'm still not certain that it's possible to enforce both directions at the same time though. I will endeavour to find out... Watch this space.

Obviously it's better not to take risks with cameras, just as it's better not to take risks with the traffic. There's plenty of Muppets out there! oops what am I saying???

Originally Posted by SV Muppet

Each tyre that runs over the strips is detected and since the strips are a set distance apart it is a simple distance/time calculation to measure the speed.

Not sure this would work, as something like a truck with sets of wheels very close together would give completely false readings if not dead straight. (I assume each set of tyres would pass over 2 strips, so a truck cab would have 3 readings done). In fact, I'd like to see soeone computer model this to see what happens if its on a corner and an artic goes past....