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What makes designing for cycling so hard?

Brian Deegan

14 August 2017/Categories: PTRC News

The title of this piece could be read in a sarcastic tone but the aim of this piece is to show that cycling really is a complex mode to design for.  A mode in fact, about which the very question of whether it needs anything specifically designed for it, is brought into question.  I usually start cycling design training sessions with a very zen statement: There is no such thing as a cycling scheme and there is no such thing as a scheme that isn’t a cycling scheme.  The point is that you cannot design exclusively for cyclists without considering the impacts on other road users.  Likewise, you should not design for other road users without thinking about the impact they will have on cycling.  The construction of our streets and roads are perfect for cycling.  Smooth wide asphalt pavements with generous turning radii make cycling comfortable and pleasant.  The issue comes when other larger more powerful vehicles are present in numbers.  Cycling infrastructure design then becomes a matter of mitigating the negative impact of these other users so cycling can still flourish.  Effectively cycle route designers spend all their time thinking about mitigating the effects of motor traffic and very little time thinking about the actual needs of cyclists.  The assumption is that: if motor traffic could just be slowed down or even reduced in number then cyclists would get the hint and use roads which were originally designed with them in mind anyway.  If you dispute this last point then please read the works of Carlton Reid. 

The job of every engineer is to design a street that works for all users but when it comes to cycling it forces designers into difficult territory.  In busier street contexts, such as high streets, space is at a premium.  Most people would not consider cycling in these places unless dedicated space is provided and so this poses the following questions to designers: Who do I take the space from? and What if I do give them the space but they do not come?  If this conundrum is solved then a third and more complex question arises and that is: Who exactly am I designing for?  The concept of a design cycle was addressed by Highways England in their Cycle Traffic and the Strategic Road Network note.  When the maximum parameters are used a design cyclist could be travelling at 40kmph with a stopping sight distance of 47m and a turning radius of 57m.  Let’s compare this to a child cyclist who could well be travelling at 5kmph, stopping every 5m and turning without needing any radius at all by putting both feet down.  The range is huge so who do you pick.  The debate has moved on from designing for sensible 12 year olds and become more scientific but the confusion still reigns over exactly who to design for and who to, in fact, design against. 

It barely raises an eyebrow to see a sign suggesting: considerate cyclists only but how do engineers design to promote consideration.  This leads to the heart of the complexity as when engineers design for cyclists they need to design streets which instil certain behaviours in both motorists and cyclists.  With motorists, this can be straightforward as their vehicles normalise their behaviour.  They have roughly similar masses and speed capabilities and with some gentle legislative prodding can all behave in a uniform and predictable way.  With cyclists, however if you design to slow the fast and aggressive they you penalise the slow and vulnerable.  A barrier installed to slow down a person on a racing bike might exclude a hand bike user from using a route.  Likewise installing segregation past a school might encourage young people to slowly ride to school meaning commuters are trapped behind them or forced to ride in narrower more congested carriageway conditions.  This kind of thinking leads to the situation that whatever you provide for some cyclists will be critised by other cyclists.  For example a new signalised junction that provides separation in time and space protecting cyclists will inevitably delay those cyclists who were happy to move through with general traffic. 

This is not however a pessimistic piece but a plea to just take the situation seriously and think about all users.  You cannot design to make all road users happy but you can at least try.  Consideration for cyclists should not be left out because it is too hard to cater for them.  Design to encourage new cyclists and try to be forgiving to all types. Make segregation wide enough for fast cyclists to pass and it will also be wide enough for side by side social cycling.    Design for everyday cycling and think of your own ideal design cyclist.  In the legal profession, they have a definition of a reasonable man being: the man on the Clapham omnibus or the man mowing his lawn on a Sunday.  What conditions would this reasonable person want to encourage them to cycle.  If the complexity of law can be distilled down to a graspable philosophical essence then the design characteristics of an ideal cyclist could be too and our streets designed accordingly.  What would a reasonable person expecting to cycle think of the streets where you live?  Is it so hard to just be reasonable?


Brian Deegan

European Director of AltaGo





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