Sunday, 10 January 2016

Unravelling -- or, Each Road Has A (Main If Not Only) Function

Two topics I have on my 'wish list' to post about are "Presumed Liabilty" and "Priority (or, who gives way to whom?)", with my takes on what others (far more knowledgeable than me) have written elsewhere. But not today. (Sorry if that's a teaser!)

The item that caught my attention over my morning coffee today, however, was an article titled "Channeling the Flow", by Bez over on the Beyond The Kerb blog.

The issue of course is the seeming inability of UK local authorities and traffic/road planners to understand why the Dutch do what they do. In the Corbridge case covered by Bez, a road treatment that is very common indeed in the Netherlands has been adopted -- because "if it's Dutch, it must be good" (er, not always!) -- but in wildly inappropriate circumstances. Observers (and video evidence) are now confirming there is too much traffic on the road in question for this kind of layout to work and it has in fact rendered the road less attractive (and safe) to cyclists, not more.

Lessons should have been learned from previous 'experiments' of this nature in the UK!

The problem is that design is being driven (if you'll pardon the expression) from the wrong starting point. Whether this kind of road layout can work or not in any given location is not a question of traffic volumes (which can and do fluctuate) or space -- it's about Function. 

As a first-time visiting cyclist* to the Netherlands last year, it's the clear delineation of function that struck me as the key to the "success" of growth into a "cycling nation". Much about Dutch infrastructure surprised me -- and at times even confused me -- but this underlying feature was, to me, glaringly obvious. 

We cycled many miles on roads with exactly this treatment -- but it worked

on the Molendijk, outskirts of Rotterdam

on the Molendijk, outskirts of Rotterdam

between Bunnik and Utrecht

along the River Vecht
(there's a motorway just out of sight on the left, the other side of the river)

further north, alongside the River Vecht.
Again, motorway is on the other side of the river serving as
the main trunk road from the south into Amsterdam.
Many roads across the river provide access off the motorway
to villages that line the river itself. 

A short stretch of road without painted lines indicating cycle lanes,
but this is a short, narrow section of a road that is otherwise as shown
in the photos above. And you can see what happens when
 the driver of an inappropriate vehicle disregards all the
cues as to what sort of road this is and what function it serves.

In every case, the road were alternatives to nearby through routes that were clearly intended to get drivers from point A to point B as quickly and directly as possible -- and where cycling provision was neither necessary nor desirable. However, running close by and roughly parallel to the fast trunk roads, are narrower roads intended to connect people who live between towns, to the towns nearest them. It appears to be very uncommon for drivers travelling from one town to the next to use these roads -- why would they, when a fast dual carriageway nearby serves their needs perfectly?

The questions for any local authority looking at traffic flow and seeking to balance the needs of different travel modes and road users therefore need to be:

What function does this road serve?  

What type of road layout will make it obvious to anyone using this road what the road is for?

Only then can motorists and cyclists... and dog walkers.... and children walking to school... and people popping to the shop for a pint of milk and the morning paper... all be able to go about their business with minimal conflict.

* I had been to the Netherlands once before -- a wonderful city break to Amsterdam in March 2014 -- but September 2015 was my first taste of how stress-free, seamless and painless bicycle travel, even through cities, can be. 


Read more about Unravelling of Modes on David Hembrow's excellent A View From The Cycle Path blog, in particular this 2012 post. "Unravelling" refers to separating transport mode, but I see applications also to road function, i.e. a fast convenient through route will be designed differently, and look very different, from a residential access road -- hence, an unravelling of motorised traffic according to purpose can occur. 

Read more about the Netherlands' Sustainable Safety principles and policies on A View From The Cycle Path, written in two parts by David Hembrow and Mark Wagenbuur. See also Mark's enlightening explanation of the nuts and bolts of this design policy on his Bicycle Dutch blog here

Read Mark Wagenbuur's analysis of the Netherlands' Street Grid road design structure, which implements Sustainable Safety policies by unravelling traffic flow according to function

See, it all comes together!


  1. I don't know what you are worrying about Rebecca. Well, I do actually, I know exactly what you are worrying about but you shouldn't. You have every right to your opinions and a wealth of experience that gives them value. Good start.

    1. Thank you, Tony. I don't know everything and I don't fully understand what I do know! I will no doubt make mistakes and get my facts wrong. But I realised my experiences touch on and are impacted by political decisions and I am fully 'qualified' to speak to that experience, indeed to form and express opinions. So here we are. <dons flak jacket?

  2. I've been reading your blog for a while now, but rarely comment. I just wanted to pop in with a comment today to say how glad I am to see this sort of post. I think it is very helpful, and I think you have named the issue of function perfectly. I've found a similar dynamic here in the US. My city just recently put in some bike lanes along a couple of major arterial roads. It made no sense to do that at all because running parallel to both of them were wonderful, narrow residential streets that all of the drivers who are just passing through avoid. We do need better infrastructure, but simply adding a lane here or there, or replicating what worked somewhere else won't work unless we understand *why* it worked in that other place. What were the traffic dynamics like? Where are people trying to go?

    Anyway, thank you for this post. I'm very much looking forward to reading more as you move your writing more in this direction.

    1. Thank you!! I'll do what I can, speaking from my own experience and personal observations. The wider issues I hardly feel qualified to comment on and I know the throw-back response is usually "No Funding!" or similar, but I can certainly call attention to local issues, where I do understand the traffic dynamics and where people are trying to go. Thanks again for commenting -- it's nice to "know" you over on G.E.'s blog but it's also nice to know who's reading your own ramblings. ;)

  3. A very good article. It's nice to see real examples from the Netherlands, properly explained rather than the frequent "well it works in NL" examples, taken out of context and incomplete. There are so many places I know here where the bypass has been built long ago, but the original route remains a busy through road with angry, speeding drivers.


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