Cycle Traffic and the Strategic Road Network – Cycle Traffic

In October, without a huge amount of fanfare, a new Highways England ‘Standard’ was released, entitled ‘Cycle Traffic and the Strategic Road Network’.

Importantly, this is not merely cycling design ‘guidance’. It sets out, quite explicitly, requirements for how cycle traffic should be designed for when it travels along, or crosses, or engages with, the Strategic Road Network (SRN), the roads administered by Highways England. Over the course of this week I’m going to look at this document – which has the unglamorous reference title ‘Interim Advice Note 195/16’ – in a series of posts. It’s 68 pages long, and there’s a large amount of important detail in it, so it’s worth examining thoroughly. It’s not completely perfect, it isn’t sexy or exciting in appearance, but, crucially, I think it raises the bar massively in terms of design quality, and in terms of user consideration.

Although IAN 195/16 does contain recommendations, and design advice, much of it sets out minimum standards and requirements – in particular, things like gradients, design speeds, widths, and so on – and states that designers to have to apply for a ‘Departure from Standards’ where they feel they cannot (or choose not to) meet those requirements.

The following definitions are used –

• “Must”: is used in this document to denote a statutory obligation.
• “Shall”: is used in this document to denote a requirement.
• “Should”: is used in this document to denote a recommendation.

So in the very first paragraph of section 2, entitled ‘Cycle Traffic’,we have the passage

Highways England and designers shall plan to acquire land to create the space to accommodate cycle traffic as part of new scheme designs (see Section 1.3) or when enhancing cycling provision for existing routes with NMU prohibitions.

… the ‘shall’ here denotes a requirement – this is something designers have to do – they have to plan land acquisition, alongside new road schemes, to create cycle provision. Likewise (shortly after) –

Infrastructure shall provide sufficient capacity to accommodate growth in volumes of cycle traffic.

… is a requirement that cycleways should be wide enough to deal with future demand, not just the existing (greatly suppressed) levels of use. IAN 195/16 states that designers shall use planning guidance to account for future cycle traffic.

We then, pleasingly, have reference to these familiar five principles, explicitly taken from Dutch design guidance.

Note again the repeated use of the word ‘shall’ (requirement) here, rather than ‘should’ (recommendation).

After this IAN 195/16 moves swiftly to ‘Facility Selection’, based around one of the most significant tables in the document – a speed/volume separation requirement.

This is what designers have to do for cycle traffic on the SRN, without applying for a ‘Departure from Standards’.

Any vehicle flow above 5,000 vehicles per day, regardless of speed limit, requires physical separation of cycle traffic from motor traffic; any speed limit above 30mph also requires physical separation. Painted lanes or ‘quiet streets’ are only appropriate at 30mph or below and with motor vehicles flows below 5000 per day. (The document also notes that if actual speeds are higher than the posted speed limit, then that is the category of provision that should be considered).

This doesn’t quite match with the Space for Cycling requirement of >2000PCU/day and speed limits of >20mph both requiring physical separation. I suspect that painted lanes on a road carrying 5,000 vehicles a day and with a 30mph limit are not genuinely inclusive. Nevertheless it is a very good foundation, especially given that these are minimum requirements. Sharing (or ‘combined traffic’) is not appropriate above 30mph; nor is it appropriate above 5,000 vehicles per day.

We also have the important provision that ‘if actual speeds are higher than a speed limit, and are unlikely to reduce through control measures, then consider the next highest category of speed’ – i.e. cycle facilities should be appropriate to the speed that people are actually driving at, not simply matched to a (potentially unrealistic) speed limit.

Speed is also crucial when we are considering how cycling itself should be designed for. We have this important requirement –

Cycle traffic shall be separated from pedestrian and equestrian traffic in order to allow cyclists to travel at the design speed.

No shared use footways, in other words. The design speed being 30kph, or 18mph, on the flat, and 40kph (25mph) on downhill gradients of 3% or more –

Absolute minimums are permitted only under specific circumstances.

The type of vehicle that is being designed for is hugely important too, and it is really encouraging to see this kind of document putting non-standard cycles front and centre – these are, after all, the kind of vehicles (and users) that will be excluded from the network if it is not designed properly.

A handcycle is the first image we come to in this section.

The ‘Cycle Design Vehicle’ – i.e. the standard unit size that designers must account for – has dimensions given as 2.8m long, by 1.2m wide, accommodating things like tandems, longer cargo bikes, and bikes with trailers, as well as wider cycles like hand cycles and trikes. There are diagrams giving dimensions for these vehicles.

It’s also good to see things visibility envelopes (for stopping distances) taking account of different potential users too.

Finally, for this ‘introductory’ design basics segment of the document, we have stipulations on horizontal and vertical alignment, and on gradients.

‘A good horizontal alignment will not include diversions or fragmented facilities’ is a clear, concise way of stating that cycle provision should not meander, and should be straightforward and continuous. Changes in direction should be provided by ‘simple curves’ – because that is how people change direction, not at sudden right angles! – according to the following dimensions.

Similarly for vertical alignment, we have a stipulation that gradients (just as with horizontal direction) should not change dramatically – ‘For comfort, there shall be a minimum sag K value of 5.0’, where ‘K’ is essentially an expression of how quickly gradient changes over horizontal distance – the smaller the ‘K’, the more quickly gradient is changing.

Finally, stipulations for gradient ensure that steep slopes are never encountered, and that steeper gradients are only encountered for short periods.

If these criteria cannot be met, then ‘earthworks shall be provided’ or the ‘horizontal alignment adjusted’ to bring the gradient into line.

That’s a good place to end for now. The impression created from these initial paragraphs is, clearly, that the title of this document is quite deliberate. Cycles are indeed ‘Traffic’ and should be designed for accordingly, with just as much care as for motor vehicles on the road network.

In the next post we will look at what ‘Cycle Traffic and the Strategic Road Network’ has to be say about cycle facilities in particular – how wide they should be, what form they should take, and the relationship they should have with the road network.