Please comment on GL area traffic study

Replies to This Discussion

Permalink Reply by JoeW on April 11, 2017 at 20:17

" Joe has done a lot of work on why in fact southbound would work better"

I did flirt with the idea of one-way southbound, since with a massive number of right-turn bans (into and out of every rung) it could be effective at reducing rat-running. I've since abandoned the idea though, since:

• even with all the right-turn bans some rung rat-running is still possible
• none of the people I spoke to who actually live on Wightman wanted it. Particularly with the latest news on the Wood Green shopping city redevelopment/expansion and several other housing developments locally, any short term reduction in traffic on Wightman due to reduced rung ratrunning would sooner or later just increase back to current levels or worse.
• the southbound package currently on the table doesn't include any right-turn bans so it's academic. (without right turn bans southbound is probably worse than northbound because right turns into Green Lanes would create further interruptions to traffic flow for buses there)
• there is a package on the table which does fully eliminate ratrunning i.e. filtering!

Permalink Reply by ant on April 11, 2017 at 20:21

Hi Joe. Actually I was wrong in the reply to John - "I do not support any" - is actually one of the options. In the survey:

Package WL: Wightman Road / Ladder area package
13. There are four alternatives for this package. Please select your preferred package (one only).
- WL1: Minor improvements
- WL2: Wightman Road one-way (northbound)
- WL3: Wightman Road one-way (southbound)
- WL4: Wightman Road closed (filtered)
- I do not support any of the alternatives

so for your comment Joe, for question 13 we do have to pick just one overall choice.

For me presently I'm deciding between WL2 and WL4.

What would be useful I think is if we did our own survey to see what sort of level of support there is for each of those options. For me at the moment WL1 is ruled out due to the unfairness of the Warham direction change. If WL4 looked like it had a significantly enough high level of support I'd probably go for it but from what I can tell anecdotally there is a lot of opposition to WL4.

(I'll respond to Hugh's long post about the Warham change tomorrow)

Permalink Reply by JoeW on April 11, 2017 at 21:17

"for question 13 we do have to pick just one overall choice"

Sorry Ant, I stand corrected! I've only skimmed through the survey and not completed it yet, hadn't actually looked as far as Q13 yet.

I still think the concept of voting "tactically" doesn't apply in a survey, just indicate at Q13 which one you prefer the most. You can still indicate your level of support or opposition to the other options within each of the four packages at Q5-12.

Permalink Reply by AndrewAW1 on April 11, 2017 at 12:13

There is another option that traffic may stay on Green Lanes either until Endymion or down to Seven Sisters. Going straight through at those lights is very easy which is why so many do it but turning right off Green Lanes is more of a hassle and I think a lot of drivers would quickly give up attempting that.

More realistic (in the longer term after the traffic settles down)) would be 20% or so of traffic going up Mattison.

There would be a potential issue at the Endymion junction though, during rush hour, with the bus stop near Homebase, it already tails back fairly badly. This would probably make it worse.

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Permalink Reply by John McMullan on April 11, 2017 at 13:46

Mattison is home to a large school and a church and also has the New River to cope with so if you're looking for a fairer alternative to Warham then traffic there will impact fewer "voters". Let's go for it eh? Screw the kids, they should move out of London if they don't like breathing the pollution.

Permalink Reply by Michael Anderson on April 11, 2017 at 13:51

There's a proposal to move be that stop south of the junction which makes sense

Permalink Reply by Hugh on April 11, 2017 at 17:57

I think, Ant, that your response may demonstrate why people haven't attempted to answer the question. You make a number of sweeping assumptions without a good basis. Joe's response begins to highlight the problems with your assumption.

Firstly, there's the assumption you make about the direction that the traffic currently takes on exiting Warham. In the absence of any data to the contrary, I'd assume 50% northbound and 50% southbound. Secondly, as Joe points out, there is no way that cars will wait patiently in line to make a right turn onto one rung road in particular when other options are available. Indeed what we do know about rat-run traffic suggests that it will seek to take the route with the fewest possible obstacles, in this case this will mean above all else the least amount queueing. In the first instance this is likely to mean that a good proportion will avoid the stretch of Green Lanes between Salisbury and Endymion if it can, particularly at its busiest times.  So many, perhaps even most, will either turn right on to Green Lanes at Salisbury or will exit via Harringay/Colina. Once it's on Green Lanes it will be split between Seymour, Allison, Effingham, Falkland and Green Lanes itself.  Of course some drivers will continue to choose to turn left out of Salisbury. After that they will more than likely wish to avoid queueing and so at most times of day will choose between Mattison, Cavendish, Umfreville and Green Lanes itself, according to where the queue is the smallest. 

So, to recap:

1. A good proportion of the traffic currently using the Salisbury-Warham rat-run will avoid Salisbury Road altogether and will reroute to  the Harringay-Colina exit. It then has four routes on to Wightman or may choose to continue on Green Lanes.

2. A proportion of the traffic that continues to use Salisbury Road will start to turn right on to Green Lanes. It then the same options as the Colina traffic.

3. The remainder of the traffic will turn left on to Green Lanes. It then has three routes on to Wightman or may choose to continue on Green Lanes.

I've made some guesses below about how some of the traffic would reroute itself, but I'm not sure they're worth the screen-space they're written on.

In a perfect world, where the redistribution were completely equal,  this would mean 1,900 cars per day per alternative route. Because this world isn't perfect, let's say that the nearest roads get double their share of the redistributed traffic. Going north, this would mean Seymour's traffic increasing from just shy of 4,000 to less than 8,000. Allison would increase from 6,500 to 10,500. Mattison would go from 7,400 to 11,400 and Cavendish from 6,700 to 10,700. Alternatively, if public opinion felt it necessary to protect Mattison Road because of the school, there could be a timed ban on right turns from Green Lanes into Matttison during weekday school hours. The burden might then shift to Umfreville.

Given the uncertainty of these guesses, perhaps it's best simply to underline that there will be 9 alternative routes for the displaced Salisbury-Warham rat-run traffic. I think it's impossible to conceive any other result than that this traffic will be distributed amongst the routes I've mentioned in some proportion or another. There will also be some evaporation. Whatever is the degree of uncertainty of these guesses, I think they demonstrate the complexity of the possible outcomes and, despite everything, I think they offer a far more realistic scenario than the one you posit. 

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Permalink Reply by JoeW on April 11, 2017 at 19:23

(Much as I'd like to take the credit, I think it may be Andrew's response you're building on not mine Hugh?)

Permalink Reply by ant on April 12, 2017 at 10:11

I was quite open about the assumptions, and I think we have a reasonable idea of how things work after the experience of the Hewitt no-right-turn and the bridge closure. Most traffic just goes to the streets either side of the change, and not so much will evaporate. Even if a whole lot did go north instead of south and spread out further away than the next street then that just risks Effingham becoming busier than Warham was. But I also think from the current layout that its most likely there is more than 50% going south bound, even the consultants predict the most significant effect will be a big increase for Mattison.  The whole thing just seems reckless to me given that lack of data about the current traffic flow and lack of traffic modeling with the change. I don't think a change of this nature should be buried within the "minor improvements" package, and why does Warham get such favoritism -  Beresford is still suffering from the Hewitt "trial", and rung roads like Effingham and Fairfax are really busy too. I think we should hope for wider spread improvements across the Ladder from the traffic study.

Anyway, this is all a bit academic if we choose one of the other packages that don't include this Warham change. Like I've said I'm tossing up between WL2 and WL4. Joe and John McM are rooting for WL4, and I suppose LW is too. I think another steering group member the HCC prefers the one-way options right? From your comments it sounds like you might favour WL1 (minus the Willoughby fix)? And John D perhaps "I do not support any of the alternatives"? What about the rest of you, what will you choose for Q13?

Lets find out - take the straw poll here!

Permalink Reply by Hugh on April 12, 2017 at 11:35

I'm not sure what lessons there are in either of the recent traffic changes you mention, Ant. I don't think we have any idea of what would happen. That's my point.

In the case of the Hewitt change, it seems to have been a simple transposition of one road for an almost identical one. The Warham change would be completely different. Drivers will have many choices, none of which exactly replicate heading straight on out of Salisbury. Any drivers choosing to turn left to use Mattison, or any other southern rung road, would be required to queue to turn right across a busy road to complete their manoeuvre. I can't see many drivers happily joining a long queue to do that where there are plenty of readily available alternatives.

We already see locally how drivers react to queueing on their chosen rat-run. You can regularly witness drivers on St Ann's Road who approach Salisbury Road with the intention of turning into it, divert to continue to the Colina route if there is a queue on Salisbury. Drivers won't wait. They'll move on to the path of least resistance, to what they hope is the next clearest route.

In the event of the proposed Warham change, there would be many very local alternatives. The problem with the bridge closure was that there were so few alternatives. The railway line created a barrier to the west and the east Harringay road closures one to the east. Drivers had very few local options.

I may have missed the part where the consultants predict levels of flow to particular roads, but what I read was they they highlighted three roads in particular - Seymour, Effingham and Mattison - without suggesting how traffic would split between them. But hey, experience has taught me not to put too much faith in what's said based mainly on opinion anyway (whether it's the consultants' opinion or anyone else's). 

You'll note that in my draft response I've supported the reduction of traffic on Warham as a principle but not necessarily the proposed measure. As with many of the other proposals, my point is that we have insufficient information at this stage upon which to reach conclusions. What I was intending in my response to you is to draw attention to the fact that we don't know what will happen in the event of Warham being reversed. We don't know where the traffic will go. As you point out, no modelling has been done on this. What I wanted to do was to question your expressed certainty that Mattison would bear the brunt. 

As to which of the four options I support, I'm not sure I support any of them in their entirety. The steering group experience was quite unsatisfying in that most of the residents who attended didn't feel very much listened to, let alone able to have influence on what went into this round of the consultation.

Given the very high traffic levels on Warham, it seems to me that finding some relief for Warham ought to be important, but not at any cost. (I think you'll find that people who live on Warham don't currently feel very much favoured in the traffic stakes, by the way, nor is it likely that they will feel favoured by having their traffic reduced to a more reasonable level). On top of that I'd like to see a reduction in overall traffic flow on the Ladder. There are realistic ways of achieving this without turning it into a one-way system or creating physical barriers on Wightman, but they're not on the table. So, as things stand I'm not sure which complete package I'd vote for, if any. 

Permalink Reply by Michael Anderson on April 12, 2017 at 12:01

Ant, why do you think there is favouritism with the proposal to change the direction of Warham Road? Who do you think is doing this favour and why?

I imagine that the proposal is on the table because it's relatively cheap and also benefits Salisbury Road. It is of course entirely legitimate to question whether this proposal is right and if it will have any negative impacts but I think that using a term like "favouritism" is divisive and unhelpful.

Permalink Reply by John McMullan on April 12, 2017 at 13:22

The closure of Wightman Rd is also going to be VERY cheap. As an added bonus it will mean that Thames Water and British gas can stop their rolling repairs of the services under the road.

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