There was a bit of back-and-forth on social media last week on the subject of Exhibition Road, involving – in particular – the Conservative councillor Daniel Moylan, who had a major role in pushing the ‘shared space’ scheme through.

One of his tweets was – for me at least – particularly intriguing.

I think I would rather hide in a cave than adopt “Sustainable Safety” principles. — Daniel Moylan (@danielmgmoylan) November 11, 2017

Fairly clear! But why might a fan of ‘shared space’ be so hostile to Sustainable Safety – the policy which lies behind the Netherlands world-leading road safety record? After all, the Netherlands is the country where Moylan’s version of ‘shared space’ largely originates – with the ideas of Hans Monderman.

If we look at the principles of Sustainable Safety, the answer quickly becomes clear. The ideology behind Exhibition Road (and Moylan’s attitude towards how it should function) stands almost directly in opposition to those principles.

Let’s take the first principle – Monofunctionality, or Single Function Roads.

This is a bit of jargon, but it essentially means that every road and street should be classified according to its function. The Netherlands has three categories –

Access road

Distributor road

Through road

There should be no ambiguity – a road should either have an access function, a distributor function, or a through-road function. Since the early 1990s, when Sustainable Safety originated, The Netherlands has been busily classifying their road network, and adapting their roads to ensure that they function according to their classification. In particular, access roads must not have through traffic using them. They are places where people live, work, shop – where they engage in everyday human activity. Flows of through traffic should, quite rightly, be separated from these activities.

Exhibition Road, of course, doesn’t fit neatly into this typology. It very obviously has through traffic on it, exemplified by the long queues of motor traffic at either end. But at the same time it has the pretence of being a place – a ‘cultural heartland’, a destination for tourists and visitors to London. So it’s a curious hybrid of public space, where people gather, and a busy through-route for motor traffic, with something like 13,000 motor vehicles per day at the northern end, and around 8,000 per day at the southern end.

Under Sustainable Safety principles, this isn’t acceptable – something should have to give. Either through motor traffic should be restricted (with access still allowed for residents), with Exhibition Road becoming a genuine access road, or alternatively the design of the road should be altered to more explicitly reflect its function as a through-route for motor traffic. At present, Exhibition Road is a through-road dressed up like an access road.

The second principle of Sustainable Safety is homogeneity of mass, speed and direction.

Again, this is a bit of jargon, but what it amounts to is that, on roads and streets, we should try to only mix things if they are of similar mass and speed, and if they are travelling in the same direction. If we can’t do this – for instance, if we can’t ensure that things are all travelling in the same direction, like on a motorway – we should try to ensure that mass and speed are equalised as much as possible.

Applying this principle to Exhibition Road, we find that we shouldn’t be mixing low-mass objects like human beings with heavy mass objects like coaches, buses and lorries (and to a lesser extent, vans and cars). These kinds of large mass vehicles shouldn’t really be on the kind of street where there are many people milling about. And if they do have to be there, we should be careful to make clear which mode belongs where, and to separate them as much as possible.

Yet this is of course the exact opposite of the ‘shared space’ ideology that lies behind Moylan’s vision of Exhibition Road – namely, that the distinction between low mass objects like human beings and have motor vehicles should be deliberately blurred, apparently to create uncertainty, and to foster ‘negotiation’ between people walking, and people piloting large vehicles. This is even in the face of evidence that the vast majority of people simply don’t want to ‘negotiate’ with those large vehicles. While it is arguable the the design of Exhibition Road may slow motor traffic more than the previous road design – which had pedestrian guardrail – in other respects it stands in direct opposition to the homogeneity principle.

The third principle of sustainable safety is that road design should be instantly recognisable.

Users should know, just by looking at a street or road, what kind of behaviour is expected from them. To quote Mark Wagenbuur’s excellent summary of Sustainable Safety –

Road design should be so consistent that road users instantly understand what they can expect and what is expected of them on a certain type of street or road. The road design itself gives information about the type of road/street. If the street is paved with bricks, there are parked cars and the street is shared with cyclists and gives access to homes, the road user will instantly know and feel this is a 30km/h (19mph) local access street. However, if the road has two carriageways separated by a median, there is no parking and cyclists have their own cycle paths, it is clear to the road user that this is a through road.

By this stage you will of course not be surprised that this is the direct opposite of the impression created by the design of Exhibition Road. It attempts to looks like an access road where people should be driving very slowly and carefully, yet has a through road function, with plenty of motor traffic moving in a straight line down the road. The impression for all users is one of confusion, rather than clarity (and again, this is an apparently deliberate hallmark of this ideological form of ‘shared space’).

Instantly recognisable road design should be predictable, and not spring surprises on users; it should have clear and consistent design types, rules and markings. This doesn’t fit at all with Exhibition Road, where a through road is composed of unusual and ‘uncertain’ design elements.

The fourth element of Sustainable Safety is Forgivingness. This principle acknowledges that human beings are fallible and that we will make mistakes, and indeed that sometimes we will deliberately break rules. Our road and street environments should therefore be designed to accommodate these mistakes and rule-breaking, without serious consequences.

This attitude to human nature – both our fallibility, and our propensity to deliberately break rules – flies in the face of Moylan’s rather sunny attitude to human behaviour, which assumes that drivers will always be benign and kind-natured, won’t deliberately break rules, and will respond rationally and sensibly to the environment around them –

The first [principle of shared space] is to do with respect for other people, and acknowledging their rights and their autonomy, their responsibility to make sensible decisions for themselves and in relation to others.

Sustainable Safety, quite sensibly, doesn’t take this benign view, and builds safety into our road environments by recognising that we human beings will often make mistakes, and make flawed judgements, rather than relying upon our supposed good nature and responsibility.

Finally, the fifth principle of Sustainable Safety is State Awareness. In short this amounts to education of users to ensure that they are familiar with rules and how they operate, but it also includes the recognition that not all human beings are the same. Some may be more prone to risk taking; some not so good at processing information, determining speeds, and so on (e.g. children, the elderly). The environment should align with these capabilities, rather than with those of some idealised human being. This is particularly important if the ‘task demands’ being loaded onto a user exceed their capabilities. A good example might be someone who is tired, or ill, attempting to drive across a junction that is needlessly complex. The risk of collisions will obviously be increased if the demands being placed on a user – in the form of multiple interactions having to be dealt with and processed in quick succession – exceed their abilities.

While conventional Dutch road layouts aim to simplify and reduce the number of interactions that have to be dealt with at any time, applying ‘shared space’ on busy roads, with many different types of objects moving in different and unpredictable directions at different speeds, will challenge the ability of people to process information and adjust to it. Again, we see that ‘share space’ of the Moylan form doesn’t sit easily with Sustainable Safety.

So there we have it! I hope that’s a reasonably clear explanation of the principles of Sustainable Safety and why it stands opposed to the ideology behind Exhibition Road.

You can read more about Sustainable Safety on the Cycling Embassy blog, on the Bicycle Dutch site, and on A View from the Cycle Path.