[Stubbs]

Today Adam learnt what 'average' means! 

[Footwork]

Today Adam learnt what 'average' means! 

4 and a half inches?

[north_country_boy]

Yes the safety issues that will be dealt with by dualling the A9 in 11 years time - obviously an excellent idea (and has been useful so far with the new Dalwhinnie dualling and the Moy area overtaking lanes), which makes wasting money on the average speed cameras (a problem not a fix) even more farcical in comparison.

...which won't happen over night, obviously. Speed limits and average speed cameras aren't the problem, people driving irresponsibly is.

[Fiend]

Yes, obviously. And this won't stop them. It's still perfectly possible to drive irresponsibily AND stick within the average speed limits - and the average speed cameras are going to encourage more people to do so (more and slower queues as said before).

[GazM]

I've just come to the end of a 3 year stretch of work that meant 1 or 2 laps of the A9 from Inverness to Perth and back each week and have to agree with Fiend.  Although the long term aim of dualling the road will be great, the short term average speed controls will make it a pretty tortuous drive. 

I heard a wee soundbite from Police Scotland saying that putting up the average speed cameras (even though they're not yetworking) was already a success as it had decreased the amount of speeding on the A9.  As far as I'm concerned success should be measured by a reduction in accidents, not in the breaking of arbitrary limits...

[a dense loner]

How do they know it had decreased the amount of speeding if they're not working? Must have had a cop with a radar at every set of cameras 

[Sloper]

The only real costs in average speed cameras is in their installation, after that, in real terms they're pretty much cost free.

It's been a few years since I used to have Janes Police Professional at work (no I don't miss it) but about 10 years ago a single camera would cover three lanes with AIR up to a staggering volume, hence 3 cameras now will give c.100% coverage.  They even work if you're in the shadow of one camera but then get spotted by the next.

They work on a simple time/distance calc and probably on 10%+2 mph but I wouldn't risk it if you're in an average speed zone the time saving on 50mph vs 57 mph is basically the time it takes to work out how much the extra insurance is going to cost when you get a ticket.

[tomtom]

I might have said this earlier - but its worth checking how your speedo compares to actual speed. GPS on phones will be accurate for this if you have a speed app or GPS app for your smartphone. On my 3 YO Golf, 50 actual speed = 55 on the speedo...

[psychomansam]

FWIW, in the average speed zone heading south from Sheffers on the M1, I can stick my speedo at 60 and cruise.

[Lund]

One random point... the cameras need to be in pairs.  This is I think because they need to agree precisely (for some definition of precisely) on what the time is - or else you'd get legal challenges on accuracy I expect.  I'm not sure how exact they are or need to be.  I work in an industry where a nanosecond is a long time, and the technology required to get more than two things to perfectly agree on sub-second timings is needlessly expensive although not complicated.

So, I think this means that the in camera and the out camera both need to see you.

What's the field of view of a camera?  I've heard it's lane sized.  (Hence 3 lanes, 3 cameras.) So... you might get away with it if you change lanes I guess.  Of course, you don't know what the pairings are.  In a stretch with 6 sets of cameras, that's several lane changes to get right...

[dr_botnik]

Or you could do a Millenium Falcon and cling to the exhaust of a Star Destroyer lorry

[Sloper]

One random point... the cameras need to be in pairs.  This is I think because they need to agree precisely (for some definition of precisely) on what the time is - or else you'd get legal challenges on accuracy I expect.  I'm not sure how exact they are or need to be.  I work in an industry where a nanosecond is a long time, and the technology required to get more than two things to perfectly agree on sub-second timings is needlessly expensive although not complicated.

So, I think this means that the in camera and the out camera both need to see you.

What's the field of view of a camera?  I've heard it's lane sized.  (Hence 3 lanes, 3 cameras.) So... you might get away with it if you change lanes I guess.  Of course, you don't know what the pairings are.  In a stretch with 6 sets of cameras, that's several lane changes to get right...

The field of view with the very early models was limited and while it could cover three lanes the question was one of capacity, but as of 2002 models were being advertised with 1 camera with 3 lane coverage.  There is a question of shaddowing i.e. sitting behind / beside a HGV but this is mitigated by multiple cameras with coverage of different 'spots' on the road.

Of course you need an 'in' and an 'out' camera but these needen't be sequential.

The question of 'where' they 'snap' you is an interesting one, but imagine (at a guess) it would be dealt with by a narrow focus / field of vision. 1m/s is about 2.25 mph so if their accuracy was =/- .5m then this would give a variation of <5 mph, so perhaps if you add a tolerance of say 2 mph then this would get close to the old 10% + 2mph 'threshold'.

The long and the short of it is that keeping to the limit really doesn't cost any time, 10 miles @50 mph is 12 minutes, @ 60 it is 10 minutes. I'm not sure of the longest stretch of average speed cameras, it's probably the A14 but that's a 70 mph zone and even if it's 25 miles long doing 80 will save you a whopping 3 minutes, which if you get done works out at a whopping £1200 per hour without the loading of your premium.

[Grubes]

I have been driving almost full time for my job since december. I have also been on driver training courses etc. so I have been a lot more careful lately with my speeds.
I usually go through average speed limits at around 50-52 mph on my speedo

I definately find the 50mph section more dangerous and stressful than any other sections of a motorway. The M62 was a great example of the dangers of 50mph zones. During the 18 months of road works they averaged around 2 accidents per week in the stretch between Huddersfield and Leeds (11miles stretch of road).
Plus lots of people breaking down on the motorway blocking the lanes.

What they did not tell people was now they have the variable speed limits with cameras on gantries. The cameras are on full time not just when the lights are on. Lot of people got done doing 80mph when they first got rid of the 50 zone.

Also the 10% thing is not necessarily true most of the time yes. It is up the the person/council that set the camera. If its a very risky area (school zone etc) some cameras are set a 31 or even 21.

[tomtom]

I definately find the 50mph section more dangerous and stressful than any other sections of a motorway. The M62 was a great example of the dangers of 50mph zones. During the 18 months of road works they averaged around 2 accidents per week in the stretch between Huddersfield and Leeds (11miles stretch of road).
Plus lots of people breaking down on the motorway blocking the lanes.

As I may have said earlier - aside from the narrow lanes the danger of these sections are the very small relative speed differentials. Normally there is more difference between speeds of cars in different lanes and in the avge sections it's really easy for cars to slowly move into blind spots and be forgotten... Also people tailgate more at lower speeds..

I prefer to go a little faster 55ish and stay in the outside lane when it's busy in these.. At least you only have to look out for arseholes moving into you from one side...

[Tommy]

Damn it.... after all my avoiding of UK average speed cameras, I just got done on (well, I've received the notification in the post from France) one outside of Chamonix on the motorway! Arse. I didn't even know they had cameras there.

Swings and roundabouts eh?!

[Stubbs]

The French ones are big metal boxes on the ground behind the crash barrier, about the size of a wheelie bin, not painted a nice hi viz like ours! They also have some average speed ones on the autoroutes, I remember once heading south late at night and an overhead sign flashing up "Voiture (my numberplate) trop vitesse" that freaked me out enough for me to slow down!

[turnipturned]

and then slow down for the individual cameras... As if that will change things.

Aslong as they slow down for every camera, this will work. You can go at 100 all the way, but as long as cameras only clocks you at 50, by slowing right down you are safe. Or am i missing your point?

Adam sounds like you might be getting some speeding tickets soon    Anyway to save you getting anymore, not sure if you are aware, but if you haven't reclassified your Van as a camper on your VO5 then you can only do 60 on a motorway and dual carriageway and 50 on single carriage way! And Yes speed cameras do pick up Vans. Just been on one of those speed awareness course, 90% of who attend were van drivers unaware of speed limits.

[Adam Lincoln]

and then slow down for the individual cameras... As if that will change things.

Aslong as they slow down for every camera, this will work. You can go at 100 all the way, but as long as cameras only clocks you at 50, by slowing right down you are safe. Or am i missing your point?

Adam sounds like you might be getting some speeding tickets soon    Anyway to save you getting anymore, not sure if you are aware, but if you haven't reclassified your Van as a camper on your VO5 then you can only do 60 on a motorway and dual carriageway and 50 on single carriage way! And Yes speed cameras do pick up Vans. Just been on one of those speed awareness course, 90% of who attend were van drivers unaware of speed limits.

Mines a camper mate. I had it changed on V5.

[turnipturned]

and then slow down for the individual cameras... As if that will change things.

Aslong as they slow down for every camera, this will work. You can go at 100 all the way, but as long as cameras only clocks you at 50, by slowing right down you are safe. Or am i missing your point?

Adam sounds like you might be getting some speeding tickets soon    Anyway to save you getting anymore, not sure if you are aware, but if you haven't reclassified your Van as a camper on your VO5 then you can only do 60 on a motorway and dual carriageway and 50 on single carriage way! And Yes speed cameras do pick up Vans. Just been on one of those speed awareness course, 90% of who attend were van drivers unaware of speed limits.

Mines a camper mate. I had it changed on V5.

Nice one. God knows why the speed limit changes??

Need mine reclassified as a camper as well, its hard work driving about at 50!

[Sloper]

The limit changes due to the fact that vans being used to transport goods are often heavily laden which increases the breaking distance at any given speed (beyond at a guess aboout 20 mph).

[Fultonius]

Take a van, cut some holes in it with a hacksaw, add some water works, furniture, gas and cooker, vaguely bolted in the back and VOILA - you can now do 60 instead of 50. 

[Sloper]

If you fail to declare modifications or make a false declaration to your insurer or the DVLA then your insurance is void(able) and potentially you're driving without insurance.

[cheque]

... not painted a nice hi viz like ours!

When I started driving I was amazed to discover that speed cameras were all painted yellow and had signs warning you when they were coming up as for years I'd listened to people talking about how sneaky and underhanded the cameras were.

It still seems strange to me that they're made so obvious- more of a test of whether you're looking for them than a tool to make you stick to the speed limits!

[Lund]

Damn it.... after all my avoiding of UK average speed cameras, I just got done on (well, I've received the notification in the post from France) one outside of Chamonix on the motorway! Arse. I didn't even know they had cameras there.

Swings and roundabouts eh?!

Er, interesting.  I believe that the UK has refused to sign up to this scheme, and so you don't have to pay.  Is that still true?

(Was it a french registered car?  That might change things.)

[Tommy]

Yeah I was hoping it was the same - I presumed I couldn't get done. It was in a hire car though.

It's even more tricky that all of the paperwork is in french and I'm pretty shit at french!