Itchen Bridge: A Freedom of Information Update

Published 2014-03-03 at 17:39

Last Thursday, and well within the 20 working day period for response (unexpected; credit where due Southampton CC), I received the response to the Freedom of Information I made in response to the completion of the new Saltmarsh Junction at the western end of the Itchen Bridge in Southampton.

In the meantime, the internets etc. have been up in arms because the new junction is A Bad Thing. As should hopefully, be clear, my gut agrees but rather than undirected anger, more productive would be an understanding of what is wrong (so it can be addressed) and how this happened (so repetition can be avoided). I've heard from enough separate people now that Southampton CC now appear to be engaging with local cyclists on this and wider matters much more directly. A shame perhaps that we had to go through this to get there but to be at least supported.

Back to the FoI

First, I can't just repost the results of my FoI as it also came accompanied with half a page of copyright notices and other (pretty standard) prohibiting clauses. Because nothing says freedom like needing to now go to the Head of Legal, HR and Democratic Services. For the record I haven't done this, but I assume republishing permission would not be forthcoming. One could settle into an argument about public benefit or the definition of freedom but I am not a lawyer, so I won't.

Fortunately, you probably don't want to read 34 pages of LinSig anyway or you'd have FoI-ed it yourself. So instead, you'll just have to trust my professional interpretation.

FoI Questions

What follows is the things I asked for and the responses/interpretations from those responses:

Scheme Option Report

Such a report apparently does not exist, however the written response to this pretty much answers the whole thing. There are two points made.

First, some of the proposed features were not allowed under TSRGD (the law under which we place signs and markings) and were excluded. In my experience, the DfT are much less resistant to good engineering than people give them credit for so, I would doubt substantial attempts were made to try. Certainly, no special authorisations have been granted for the scheme which is a little surprising given my gut tells me that split stop lines would require separate signal phases and the right-turning cyclists (if they've appropriately studied beforehand) are intended here to be controlled by a secondary head only, and no stop line.

Secondly, and this I will quote, "The Advanced Stoplines were excluded as there was a need to seek a fine balance between junction capacity and also a safe right turn facility for cyclists[...]". Here we have the crux of the problem; I'll come back to this.

Safety Audit, NMU etc.

A suitable report was provided to me. Various items are raised and this is standard for any Road Safety Audit (it's the point of the process). In fact I'd be suspicious if nothing had been raised. Generally all raised points are addressed responsibly except unfortunately the most important one here, that of the right-turning cyclists. As we have might have guessed thus far, the response of SCC is an "extensive campaign to educate all road users". The RS Auditors in their response to the client response (side note: something which is not often done and should, in my opinion, be done more so again credit where due) at that time are clearly still concerned and note that this will be "vital".

Personally, I find this understated. Amongst my other activities, I do some computer programming. Various things I have written/designed require a graphical/user interface. There's a rule of thumb in UX (user experience) design: If your user has to be told how to use it, you've done it badly. This principle is one of the reasons why Apple was pretty much single-handedly responsible for launching the mainstream smartphone market and the same thing applies to the highway. If you need a video or a leaflet to explain how to use a junction, then you have designed a poor user experience. Advanced Stop Lines (ASLs) are road 'user experience' and are ubiquitous enough to be well understood; further reason for their retention/inclusion.

Modelling Outputs

These were provided to me in the form of a LinSig report. Generally, the modelling is adequate (though I have some technical issues with it) and I could go into painful details but I won't save for summarising. In traffic engineering parlance, the junction does not operate satisfactorily in the AM peak. What this means is the junction is over capacity. I have no baseline Arcady (roundabout modelling software) for the roundabout to compare to, but the signals are likely lower in capacity and this indicates liable to cause congestion.

Obviously, traffic will readjust and vehicle congestion isn't the be all and end all, except, in Southampton, almost everyone drives and angry drivers don't re-elect people. Further, and perhaps less dramatically, as a highway authority, Southampton CC is bound to a Network Management Duty which means they must secure the "expeditious movement of traffic", albeit that traffic is defined as all road users. In that vein it should be noted for non-locals that the Itchen Bridge is a key bus corridor and congestion over the bridge would affect all these routes and the large number of people thereupon (which offhand I would guesstimate outnumber cyclists in the order of 10:1).

I now therefore see why the scheme is as it is, and I believe that is why the ASLs disappeared and why the additional lanes appeared. What has happened is an attempt to shoehorn as much capacity into the junction as possible given layout constraint (the junction is elevated, there is no further land-take possible). My personal view is that this should not be at the expense of the ASLs and potential as yet unproven cycle safety but this is a political decision ultimately, and nobody elected me.

Council Approvals

These were already in the public domain (who knew?) and so happily I can link to them for you. We're interested in Item 29. Interesting info includes where the money comes from and the approval of the scheme in its as-built form last August (again, who knew?).

The main questions here revolve around bigger issue of the fact nobody bothers to monitor what the Council actually does. Culpability all round on that one I think.


It is up for debate as to how far a highway authority should go to prioritise any particular mode over another where capacity is limited. No doubt a fair proportion of readers will be disappointed by my pragmatism on this; but any authority is bound by various network management duties, political realities and the basic geometric constraints of any given circumstance.

That being said, as a designer I would not have excluded the ASLs. Numerically, in the AM Peak, the junction does not appear (in modelling) to work anyway and I do not believe the removal of ASLs makes any difference worth their removal. In fairness to SCC, the margin by which the LinSig modelling indicates the junction is congested and yet has still been implemented is what one might refer to as 'politically courageous'. One should not underestimate the effort that would have been needed to have known this, and yet do the junction anyway.

However, the wider cyclist disgruntlement with regard to this junction continues. Some signage for cyclists so they need not watch the YouTube first might be warranted, however I would assume the Stage 3 RSA would recommend this too. One thing I am certain of is that Southampton CC Highways are monitoring the situation closely, as indeed is everyone else. I would be surprised if this scheme were not 'tweaked' as the rest of the Eastern Cycle Route materialises.