The Dimensioned Cyclist

TheDimensionedCyclingTwinsThere’s a lot to read, research and review right now in the world of new, cycle-friendly infrastructure design, but you’ll find at least one familiar character doggedly plodding his way through from one version to the next – the dimensioned cyclist.

I don’t know when he first appeared, perhaps there’s a bike-infra historian out there who does? I got into this campaigning game in about 2008 and at that time he could be found wobbling around in a 1m envelope with his twin brother in figure 2.2 of the DfT’s LTN2/08: Cycle Infrastructure Design.

The last four years of austerity have clearly had an effect in London because he’s had to move with the times and confine his elbows to 75cm, his space budget slashed in figure 3.2 of the Draft London Cycling Design Standards by a whopping 25% (along with the graphics budget).


Meanwhile, Sustrans, always aware of gender balance in its publications, has chosen to illustrate the width required by cyclists in its new design handbook with his sisters. Progress indeed.

TheDimensionedFemaleCyclistNow, if I were to spend an afternoon flicking through the Design Manual for Roads and Bridges, God forbid, how likely is it I’d come across a whole section devoted to the dimensions of one of the most common cars on the roads today like the Ford Fiesta? Along with a footnote about larger, less common, but more problematic vehicle types to design for such as vans and lorries? The motoring equivalent of this…

2.6.1 Highway designers consider the dimensions of motor vehicles and their swept paths to determine carriageway widths, junction dimensions and parking layouts. The sizes and swept paths of cycles are usually irrelevant in the design of on­road cycle routes, but there are occasions where they need to be considered. Examples include the approach to a cycle gap, or the interface between the carriageway and an off­road cycle route. Failure to provide the room a cyclist requires can make some routes inaccessible or difficult to use, particularly for disabled cyclists, tandem or trailer users and parents transporting young children by bicycle.

For comic effect I’m being a tad unfair to Local Transport Note 2/08 because it does mention the dimensions of a couple of other bike types, but my point is you won’t find a dimensioned drawing of any other bike type. Neither does it make them easy to picture or design for.

Why are cycle infrastructure design gurus obsessed with diagrams of one type of bike? Is it because other bike types are too difficult to draw? Does showing a handcyclist in primary position feel too uncomfortable? Are bike cargo companies just a fad and not worth consideration in future cycle networks? I’d really like to know because along with other inclusive bike users it’s making my cycling life bloody miserable and turning me into a very grumpy bike-bore at parties.

But hold on a second, section 2.6.1 appears to hold the answer to the problem of designing properly for different bike types – swept path analysis. As far as I know, despite it being a commonly used tool available to highway engineers and urban designers in their chosen CAD systems, nobody applies it to model the larger inclusive bike types in cycle infrastructure design. Just think of all that computing power and graphical game playing fun going to waste!

So bike-infra bods, how about we put a stop to this perverse practice of dimensioning the stereotypical cyclist and set about properly integrating inclusive bike types into the design workflow? Embrace equality and build an accessible environment for everyone – you know you want to 🙂

9 thoughts on “The Dimensioned Cyclist

    1. Kevin Hickman Post author

      Misreading it perhaps, but not stupid :o)

      “…irrelevant in the design of onroad cycle routes…” rather than cycle paths, because roads are already designed for larger vehicles with larger turning radii. Which may go some way to explain why swept path analysis has never been used for cycles traditionally.

      But it does recognise that swept path analysis of bikes IS required for cycle paths, and off-road infrastructure. Sadly nobody seems to taken any notice of it though :o(

      1. paulc

        there’s a lot of cycling cr@pfrastructure in my local area that I can’t negotiate with my trailer attached and find difficult enough to negotiate with an ordinary bicycle…

        Two stage Toucan crossings with railings confining pedestrians in the central area can be a real pain even on a normal bicycle…

        And why, oh why do they always feel the need to stick a flippin’ chicane at the entrance and exits to cycle paths and shared use paths when they diverge or meet back up with roads??

      2. Kevin Hickman Post author

        I believe it’s down to the safety audit and the fact that it’s so cheap to ‘mitigate for cyclists travelling too fast’ by specifying cheap bollards and barriers. I don’t believe there’s any evidence stating how effective they are at preventing collisions, it’s just become a habit.

      3. Andy R

        “And why, oh why do they always feel the need to stick a flippin’ chicane at the entrance and exits to cycle paths and shared use paths when they diverge or meet back up with roads??”

        I know it may seem as though designers are persecuting you, but this is a difficult issue. I’m working on a scheme where we recommended several sites had these bollards removed, to improve access for cargo bikes and adult trikes, etc. However, the bollards were put in in the first place to prevent mis-use by kids on scooters and trail bikes – a real and documented problem prior to them being placed – therefore the bollards stay.

        At this point the cry goes up ‘What do the Dutch do?’. Well, they seem to accept that such off-road routes will be used by other than just peds and cyclists, and legislate to allow certain classes to use them legally (something I learned from ‘A view from the cycle path’). However, on the type of infrastructure we have built in the past (and, unfortunately, still build) this sort of multiple use would inevitably lead to conflict. It’s hard enough to get tracks wide enough to accommodate cyclists comfortably, to accept that they will then be used by mopeds, scooters, etc. and must be design accordingly would require a sea-change in attitudes from everyone in the UK (the public most of all).

  1. Andy R

    Unfortunately, none of the vehicle swept path analysis software I know of contain templates for even ‘the average bike’ never mind bakfiets, recumbents, tandems or adult trikes (which would finally show everyone how much space is needed to get past those access barriers). And for a designer to create a template, while easily done with HGVs (because the manufacturers are usually willing to supply the data needed), would need bicycle dynamic data that I for one have no idea where to find – if it actually exists. I’m afraid this is one for the software developers, (although, to be fair, they would probably include such templates if there was sufficient demand from engineers).

    1. Kevin Hickman Post author

      Thanks Andy. Perhaps a research project or PHD might be a way of getting it kicked off? Or persuading a big enough organisation to request it. To be honest, I’ve no idea if it’s a relatively trivial problem someone could knock off in a couple of days or something that would require hundreds of man hours.

      I wonder if I could find out…

      1. Andy R

        The two pieces of swept path analysis software that are most popular in the UK are;
        AutoTrack –
        AutoTurn –
        There’s lots of money invested in these, given the numbers of vehicles (and sometimes very specific – aircraft and their tugs, for example), and worldwide nature of their use. There may be others (including some that I believe are free), but as engineers we need software with a good reputation.
        TBH, the only time I interact with the publishers is at Traffex, every other year. Unfortunately the next one is in 2015, but it’s something I could mention – they’re always looking for ways to differentiate themselves and get a better USP.

      2. Kevin Hickman Post author

        That would be much appreciated. I notice that Transoft have a “Don’t see what you need? Let us know” option in their vehicle library.

        The videos referenced in those links have given me further cause/pause for thought too. Thanks for sharing 🙂

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