The third edition of the Sustainable Safety vision

Sustainable Safety is one of the corner stones of the Dutch road safety policies. Its ultimate goal is to make traffic so safe that everybody can get home safely. Not only fit able-bodied people or drivers in protected vehicles, but every road user – the schoolchild, the commuter, the commercial driver and the active senior, whether they walk, cycle or participate in traffic in any other way. I’ve published about Sustainable Safety before, in 2012 and in 2017, but the policy was updated in 2018. That is why I want to start this year with another look at Sustainable Safety. First, I would like to wish you all the very best for this new year! I also – as you will have noticed – updated the look of my blog.

Billet en français

The three editions of the Dutch Sustainable Safety policies from the 1990s, 2005/2006 and 2018 respectively.

The Dutch Institute for Road Safety Research (SWOV) published the ‘3rd edition of the Sustainable Safety vision’ in 2018. The report describes what SWOV calls ‘the latest recalibration of the vision’. The policies were first developed and implemented in the 1990s and updated in 2005/2006, making use of the experiences after the first implementation. In version 3 the terminology was updated and the original five principles were grouped in two main categories. In my first post I listed these five original principles as follows:

Sustainable Safety principles (2005-2018): 

1. Functionality (of roads)
2. Homogeneity (of mass, speed and direction of road users)
3. Predictability (of road course and road user behaviour by a recognisable road design)
4. Forgivingness (of both the road/street environment and the road users)
5. State awareness (by the road user)

Since the 2018 update the five principles have been rephrased and ordered in two main categories:

Three design principles:

1. Functionality of roads;
2. (Bio)Mechanics: limiting differences in speed, direction, mass and size, and giving road users appropriate protection;
3. Psychologics: aligning the design of the road traffic environment with road user competencies.

Two organisation principles:

4. Effectively allocating responsibility;
5. Learning and innovating in the traffic system.

That it is safer when behaviour of other road users is predictable and speed and masses are similar, while oncoming traffic is separated, is widely understood and accepted when it comes to motorway design.

The design of Dutch main rural roads tries to keep many of the motorway safety features by splitting the directions in separate carriage ways and reducing the number of at-grade crossings.

Even main roads in the urban areas have been made as predictable as possible by keeping different types of traffic apart, not allowing parking and having as few side streets as possible for instance.

In access streets or place, where many things will happen at the same time and the space is shared, it is essential that speeds are kept to an absolute minimum – forced by design – to give road users enough time to respond to the situation and the behaviour of other road users.

This doesn’t mean the previously explicit concepts of predictability, forgivingness and state awareness have been abandoned, they just now belong under the wider umbrella of mechanics and road-user psychology.

On a dedicated website (in English) SWOV explains the changes as follows:

• Concerning the design principles, vulnerable modes of transport (pedestrians and cyclists in particular) and the competence of older road users are the more explicit standard now.
• The third edition of the Sustainable Safety vision pays greater attention to cyclist crashes not involving motorised vehicles. [single vehicle crashes]
• Responsibility is emphasised with respect to the role and potential actions of stakeholders in realising an inherently safe road traffic system.
• Sustainable Safety’s third edition advocates in-depth analysis of all fatal road crashes to learn from the things that still go wrong.
• Furthermore, this third edition of the vision calls for a pro-active and risk-based approach, using both crash statistics and road safety performance indicators (or surrogate safety measures) as safety indicators and as a basis for action.

“Allocating responsibility” not only defines which authority has to determine what a space is for and design it accordingly; it also addresses what behaviour is desired of different groups of road users. Drivers of larger vehicles are expected to act more responsible than a child walking or cycling to school, based on the danger their vehicles pose and their education and experience. This is basically what strict liability is about.

The categorisation of roads is very important in the Dutch system. Every road can only have a single purpose. There are through roads and access streets/place which are connected by distributor roads. This system resembles earlier schemes of road categorisation from the United Kingdom in the 1960s, but the Dutch system was further refined and every type of road/street/space has been given its own design features which are easy to recognise. Picture right: Cycling Embassy of Great Britain.

Clear, clutter free, easy to understand road design that doesn’t distract is what the Dutch try to achieve. Everything ties together. The bollards (left) prevent parking where sight lines for traffic entering from the side street (right) would be obstructed. Priority for cycling over traffic entering and leaving that side street is clear from the continuous red asphalt. The side walk crossing is also level, indicating that walking also goes before traffic in that side street.

In a sustainably safe road traffic system, according to this Dutch view, everything possible is done to realise maximally safe road traffic. With the aforementioned rephrased principles in mind the approach is about:

• Eliminating: ideally, dangerous situations are made physically impossible so that people do not find themselves in such situations.
• Minimising: the number of dangerous situations are limited and certain modes of road transport are made unattractive to limit people’s exposure to risks.
• Mitigating: where people are exposed to risks, their consequences should as far as possible be mitigated by taking appropriate mitigating measures.

Streets with a 30km/h speed limit should be designed in such a way that speeding is simply not possible. In this street that is not the case. Such streets are more dangerous than zones that have been designed according to the design specifications.

The extra attention to the most vulnerable road users doesn’t come a moment too soon, because recent news reveals that road safety is not always going in the right direction.

“Last year [2019] 21,400 people were seriously injured. That number grew especially for cycling – 66% of all serious injuries is now in that group of road users. It is noteworthy that in 8 of 10 incidents no motor vehicle was involved. Moreover, many seriously injured people are over the age of 60. The number of injured senior traffic users keeps growing, according to SWOV.”

SWOV also notes that – even after more than 25 years since the policies were first implemented – there still are a lot of areas with a speed limit of 30km/h that have not been designed for that speed. In a well-designed 30km/h zone it is physically impossible to break the speed limit. That it can be done in many of those zones is visible in the crash statistics. Many of the most dangerous neighbourhoods in the Netherlands are also in the historic city centres. That is not only due to space constraints. There are design requirements for those historic environments, such as cobble stones, that make traffic less safe for certain road users. The centres are also usually the most busy areas in the cities. A professor of the Delft University of Technology, Bert van Wee, has a (for other countries possibly) radical solution. In his opinion road managers “could consider making these areas inaccessible to motor traffic”.

SWOV itself urges to take immediate and large scale measures:

“design spaces according to the sustainable safety principles – including safe infrastructure for cycling, but keep enforcing as well.”

The latest version of Sustainable Safety is even more focussed on prevention and designing a safe system than before, but it doesn’t stop there. In collaboration with the organisation responsible for many of the Dutch road design manuals, CROW, a new project has been started as well. This “Strategic Plan for Traffic Safety 2030” with the sub-title; “safe from door to door” takes an even more holistic approach for instance regarding risk analysis (of behaviour as well as situations). This is explained in a fact sheet (Dutch only). The – updated – Sustainable Safety principles are still very much part of this new project, but it shows that road safety policies in the Netherlands keep evolving.

The first video of 2021; the 3rd Edition of Sustainable Safety.