The new Average speed cameras on the A40 /westway West Lond
Discussion
ORD said:
The 40 limit on the west way is completely ignored in my experience. You feel like you're in reverse going along at 40. It should be a 50 or 60 limit and enforced with average speed cameras. The 40 limit being enforced will just increase congestion outside of rush hour, whereas now it is an extremely good road in the early hours - fast, flows very nicely, which will all be stopped when everyone is side by side and nose to tail at 40...cue concertina braking and traffic at a standstill.
Made worse by people sitting in the outside lane at about 36-37mph on their speedo which will probably equate to an actual 35mph and they'll come out with "It's a limit, not a target" 
ORD said:
The 40 limit on the west way is completely ignored in my experience. You feel like you're in reverse going along at 40. It should be a 50 or 60 limit and enforced with average speed cameras. The 40 limit being enforced will just increase congestion outside of rush hour, whereas now it is an extremely good road in the early hours - fast, flows very nicely, which will all be stopped when everyone is side by side and nose to tail at 40...cue concertina braking and traffic at a standstill.
Yes, the effect of speed cameras on road safety will be linked to the difference between the speed limit and the maximum safe speed (hazard density etc). If the speed limit is 150mph, speed cameras will have no effect (positive or negative). If the speed limit is too low, as is often the case on the A40, speed cameras will have a greater effect on collision rates, both positive and negative.The bunching of traffic caused by average speed cameras may affect motorcyclists in particular. Average speed cameras can force motorcyclists to travel in a smaller space surrounded by cars and lorries, thereby exposing them to risk of injury for mile after mile, whereas before average speed cameras, they could find and travel in the empty spaces, reducing their injury risk.
We have yet to find out which is greater, the reduction in collisions due to the speed cameras causing lower speeds or the increase in collisions due to speed cameras causing traffic bunching, inattention, tiredness, frustration etc.
TfL could have installed their average speed cameras within simple scientific trials. If they had, we would have "proof beyond a reasonable doubt" of the effect of the speed cameras on road safety. TfL's failure to run scientific trials will make it difficult to assess their effect:
http://speedcamerareport.co.uk/02_scientific_trial...
gdaybruce said:
Speaking of Hanger Lane. what's with the 30 limit through the underpass? Absolutely no one slows down to 30 if the road's clear. The other evening I had a police car behind so actually did slow to 30. He sat behind me for 50 yards before deciding he'd had enough and pulled out and passed me!
I wrote to TfL about this limit. It isn't legally signed, the sign being on one side of the road only -- they didn't seem to mind about that. That probably isn't fatal to prosecutions involving the 40 either side but might open a 
of light to the skilled. The limit is there in case the lights in the tunnel fail while they are being upgraded, I was told.fergus said:
Yep. The average speed can be determined between any two of the circa 10 Vector cameras along the entire 13 mile route. It could be #1 and#6, #3 and #5, or between all of them, etc. etc. There is no escape. Annoyingly, there is a 30mph limit in place under Hangar Lane roundabout.
How does it handle the limit changes? And if it can handle the limit changes, why are there two cameras either side of the change from 40 to 50 at Perivale within 50 yards of each other. If it were able to handle multi-limit sections then why not just have a single camera at the change?I must say if this stopped the crashes on the A40 and meant my commute was more reliable without the occasional 45 minute delay once a month, I wouldn't mind the impact on speed. Of course I don't believe it will. And neither do the authorities: if it did make the road safer then presumably they would raise the speed limit without any consequences?
I am delighted to read in the press releases that speed cameras saved 500 deaths in the capital last year and thus there were only 124. Fishy maths?
7db said:
I wrote to TfL about this limit. It isn't legally signed, the sign being on one side of the road only -- they didn't seem to mind about that. That probably isn't fatal to prosecutions involving the 40 either side but might open a of light to the skilled. The limit is there in case the lights in the tunnel fail while they are being upgraded, I was told.
Thanks for that - it's good to know there actually is a reason for the limit, even if it's not a very good one! It illustrates perfectly how posting a limit that everyone perceives to be inappropriate (because it appears to be wholly irrational) is totally ignored. of light to the skilled. The limit is there in case the lights in the tunnel fail while they are being upgraded, I was told.Full answer here:-
"The A40 Hanger Lane Tunnel lighting is being upgraded to LED as the original lighting was in an inadequate condition to provide the required lighting levels. At the moment the old lighting units have been switched off with temporary lighting installed during preparation works for the LED. 30mph speed signs have been placed at the tunnel portals as an extra safety measure during the installation of the permanent LED lighting. The signs will be removed once the lighting has been upgraded later on this year.
This is an extra measure of safety should the temporary lighting fail for any reason."
"The A40 Hanger Lane Tunnel lighting is being upgraded to LED as the original lighting was in an inadequate condition to provide the required lighting levels. At the moment the old lighting units have been switched off with temporary lighting installed during preparation works for the LED. 30mph speed signs have been placed at the tunnel portals as an extra safety measure during the installation of the permanent LED lighting. The signs will be removed once the lighting has been upgraded later on this year.
This is an extra measure of safety should the temporary lighting fail for any reason."
These cameras go live next Tuesday.
They are already in operation but the data is not currently enforceable.
These are very advanced and they are not point to point like SPECS.
They range from the Polish War Memorial to the Paddington slip road AFTER the elevated section!
They pick you up as you enter the network and can endorse you for an excess average speed across ANY camera combination, not just the two next to each other.
Here is some more information about the cameras:
http://www.siemens.co.uk/traffic/pool/documents/br...
NOTE this bit!!!
"Self-financing
Through Siemens Financial
Services we can supply, install and
administer SafeZone equipment
based upon a customised rental,
lease or pay-per-violation basis.
As part of the pay-per-violation
service Siemens will deliver
encrypted ERCU output for
review and further action by
the appropriate organisation."
This is the user manual:
http://www.siemens.co.uk/traffic/pool/downloads/ha...
These cameras are now a major pain for me as I drive into central London between 3am and 5am Mon-Fri. I now have to maintain 40 or 50 (or 30 through the HL underpass) on EMPTY 3 lane carriage ways.
They are already in operation but the data is not currently enforceable.
These are very advanced and they are not point to point like SPECS.
They range from the Polish War Memorial to the Paddington slip road AFTER the elevated section!
They pick you up as you enter the network and can endorse you for an excess average speed across ANY camera combination, not just the two next to each other.
Here is some more information about the cameras:
http://www.siemens.co.uk/traffic/pool/documents/br...
NOTE this bit!!!
"Self-financing
Through Siemens Financial
Services we can supply, install and
administer SafeZone equipment
based upon a customised rental,
lease or pay-per-violation basis.
As part of the pay-per-violation
service Siemens will deliver
encrypted ERCU output for
review and further action by
the appropriate organisation."
This is the user manual:
http://www.siemens.co.uk/traffic/pool/downloads/ha...
These cameras are now a major pain for me as I drive into central London between 3am and 5am Mon-Fri. I now have to maintain 40 or 50 (or 30 through the HL underpass) on EMPTY 3 lane carriage ways.
Great thinking from TFL. Let's compare the two scenarios for a lighting failure.
(1) Speed limit remains at 40 under tunnel.
Cars all at or around 40mph go through the tunnel (maybe in the dark for a second or so).
(2) Speed limit is set at 30 under tunnel.
A few randomly interspersed cars obey the limit (including me). Everyone else sticks at 40. In that second, the faster driver may (in theory) bash into the back of one of the few people that obeys the limit.
Utterly stupid.
(1) Speed limit remains at 40 under tunnel.
Cars all at or around 40mph go through the tunnel (maybe in the dark for a second or so).
(2) Speed limit is set at 30 under tunnel.
A few randomly interspersed cars obey the limit (including me). Everyone else sticks at 40. In that second, the faster driver may (in theory) bash into the back of one of the few people that obeys the limit.
Utterly stupid.
Mods -- Wonder if we can merge this with thread 1523422?
There is a sign going into the tunnel that says "use headlights". The limit is odd as it doesn't end -- eastbound there's just a 40 repeater a bit further up the hill. There's a few bagged 40 repeaters along the way. Thoroughly unsatisfactory signage.
There is a sign going into the tunnel that says "use headlights". The limit is odd as it doesn't end -- eastbound there's just a 40 repeater a bit further up the hill. There's a few bagged 40 repeaters along the way. Thoroughly unsatisfactory signage.
GTO NEMESIS said:
These cameras go live next Tuesday.
They are already in operation but the data is not currently enforceable.
These are very advanced and they are not point to point like SPECS.
They range from the Polish War Memorial to the Paddington slip road AFTER the elevated section!
They pick you up as you enter the network and can endorse you for an excess average speed across ANY camera combination, not just the two next to each other.
Here is some more information about the cameras:
http://www.siemens.co.uk/traffic/pool/documents/br...
NOTE this bit!!!
"Self-financing
Through Siemens Financial
Services we can supply, install and
administer SafeZone equipment
based upon a customised rental,
lease or pay-per-violation basis.
As part of the pay-per-violation
service Siemens will deliver
encrypted ERCU output for
review and further action by
the appropriate organisation."
This is the user manual:
http://www.siemens.co.uk/traffic/pool/downloads/ha...
These cameras are now a major pain for me as I drive into central London between 3am and 5am Mon-Fri. I now have to maintain 40 or 50 (or 30 through the HL underpass) on EMPTY 3 lane carriage ways.
Interesting information. May I ask why you think they will go live on 1st Sept? Transport for London have stated: "There will be information regarding the expected enforcement of the Average Speed System provided to motorists by the local Variable Message Signs in the weeks leading up to the system going live". There has not been any mention on the "local Variable Message Signs" yet, so we should still be weeks away. This suggests mid Sept at earliest.They are already in operation but the data is not currently enforceable.
These are very advanced and they are not point to point like SPECS.
They range from the Polish War Memorial to the Paddington slip road AFTER the elevated section!
They pick you up as you enter the network and can endorse you for an excess average speed across ANY camera combination, not just the two next to each other.
Here is some more information about the cameras:
http://www.siemens.co.uk/traffic/pool/documents/br...
NOTE this bit!!!
"Self-financing
Through Siemens Financial
Services we can supply, install and
administer SafeZone equipment
based upon a customised rental,
lease or pay-per-violation basis.
As part of the pay-per-violation
service Siemens will deliver
encrypted ERCU output for
review and further action by
the appropriate organisation."
This is the user manual:
http://www.siemens.co.uk/traffic/pool/downloads/ha...
These cameras are now a major pain for me as I drive into central London between 3am and 5am Mon-Fri. I now have to maintain 40 or 50 (or 30 through the HL underpass) on EMPTY 3 lane carriage ways.
The Siemens pdf states "SafeZone ... using the proven road safety benefits of average speed enforcement systems". That statement appears to be false. I can find no proof of effectiveness in official reports of ANY speed cameras, let alone average speed cameras. For proof we require scientific trials but none have ever been run.
http://speedcamerareport.co.uk/02_scientific_trial...
In the absence of scientific trials, we can get close to proof if:
1) selection effects (RTM) have been completely eliminated from results (not just estimated)
2) trend has been accurately adjusted for
3) no other changes were made at the speed camera sites that might affect collision rates
The first has never been achieved in official reports (for any speed cameras worldwide) and the second two, if they have ever been done at all at average speed camera sites, are rare. It would be reasonable to conclude that there is no proof and that Siemens are therefore making false claims.
smashy said:
It has to be said that if there were no cameras on the N circ between hanger Lane and Bounds green that would be a racetrack with I reckon some nasty consequences
It used to be a couple of decades ago, but there were some large pile-ups. A13 was worse, the flyovers over the roundabouts used to be lethal due to poor sightlines. Blackwall tunnel approach roads were another high point, as was the spine road during the early days of the Docklands' redevelopment.Crossing Waterloo Bridge and then swooping into the Strand underpass on a Saturday morning was particularly invigorating, also the Thames Embankment generally.
And before that it was all fields.
7db said:
I remain sceptical that they can cover multiple speed limits:-
- there are two cameras Westbound at Perivale across the limit change. Why go to that expense if it can?
- magistrates struggle with averages
I agreed with that, initially. But thinking about it, it would be possible to calculate the max upper limit over a long section inc different speed limits, and prosecute above that.- there are two cameras Westbound at Perivale across the limit change. Why go to that expense if it can?
- magistrates struggle with averages
eg 50 - 30 - 50 dependent on particular distances could give a max poss average legal speed of (say) 40mph. So above that you get prosecuted. But they need the extra cameras for the individual 30 zone too, so if you did 40 through it you would get prosecuted for that section.
therefore it is possible. w
ky, but possible.ps anyone know the ksi figures for that section of road? Why has this been deemed necessary?
I agree it's possible to calculate the max legal speed (minimum legal time) between any two points. I have it worked out for my commute which encompasses everything from 30 to 70.
However it's an odd legal situation for enforcement. Doing 40 in a 30 is much clearer than "arrived in 24 seconds when only was allowed to arrive in 30". You can imagine the beak looking confused, I am sure -- but it's definitely a possibility. I think so, and you do too.
So what do the enforcement authorities think. We could just ask them to FOI whether they are enforcing across limits, but better than that is to look at their actions: They have placed two cameras within 50 yards at Perivale westbound -- across the limit change from 40 to 50. This would be unnecessary if they could enforce across the limit -- both are before the exit -- and I'm guessing the cameras aren't cheap. That tell me that they don't believe they can enforce across the limit change.
However this is not mirrored on the Eastbound side -- there is a single 50 limit camera at Perivale then a 40 limit camera immediately before the Hanger Lane exit (although oddly this doesn't have a marking in lane 3). I assume this one hooks up with the 40s round the A406 and with the camera at Savoy Circus. But does that mean it's a free-for-all from Perivale to Hanger Lane? Probably not: that's rather close to the NW Garage...
However it's an odd legal situation for enforcement. Doing 40 in a 30 is much clearer than "arrived in 24 seconds when only was allowed to arrive in 30". You can imagine the beak looking confused, I am sure -- but it's definitely a possibility. I think so, and you do too.
So what do the enforcement authorities think. We could just ask them to FOI whether they are enforcing across limits, but better than that is to look at their actions: They have placed two cameras within 50 yards at Perivale westbound -- across the limit change from 40 to 50. This would be unnecessary if they could enforce across the limit -- both are before the exit -- and I'm guessing the cameras aren't cheap. That tell me that they don't believe they can enforce across the limit change.
However this is not mirrored on the Eastbound side -- there is a single 50 limit camera at Perivale then a 40 limit camera immediately before the Hanger Lane exit (although oddly this doesn't have a marking in lane 3). I assume this one hooks up with the 40s round the A406 and with the camera at Savoy Circus. But does that mean it's a free-for-all from Perivale to Hanger Lane? Probably not: that's rather close to the NW Garage...
My thinking is (probably too simplistic) on the “multiple” speed sections is they could take the maximum for the distance between the last camera on (say) the 40mph stretch and the end of that section, then start again at the change (say 30mph) to the next camera. Thus being able to get an average speed between the two cameras – Which would be lower than the 40, but higher than the 30. Depending on distances, you could possibly travel the whole stretch initially below the limit , but then above the limit? Can any confirm/deny my logic ?
(ETA Which is what some people do now in the single limit areas - It's just more difficult to work out )
(ETA Which is what some people do now in the single limit areas - It's just more difficult to work out )
Edited by covboy on Thursday 27th August 09:51
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