So whats with the latest road safety catch cry? SCA started advocating for Sustainable Safety here in Australia at the start of the year, but many still aren't fully aware of whats involved. Taken from Institute for Road Safety Research website in the U.K., this will explain the principle in detail for all.
Sustainable Safety
A crash can happen to anybody. In a rash moment, everybody can make an error or slightly bend the rules. That is why safety guarantees are so important: the Sustainable Safety approach in a nutshell.
Over the years, Sustainable Safety has become a household concept, not only in the Netherlands but also internationally. In 1992, the original idea was launched in "Towards a Sustainably Safe Road Traffic" and its initial implementation was described in Start-up programme Sustainable Safety. Due to previous experiences, advancing insights, and new developments, the Sustainable Safety vision was updated in 2005. This exploration for the coming 15 years has been published in "Advancing Sustainable Safety". On the website www.sustainablesafety.nl you can find the integral version of the book, the brochure containing a summary, and all kinds of background information.
Goal and starting points
The goal of Sustainable Safety is to prevent (serious) crashes, and where this is not possible, to practically exclude the chances of severe injury. To achieve this, the human being is the point of departure: not only his physical vulnerability, but also his capabilities and intentions. After all, it's people who make errors and don't always obey the rules.
Sustainable Safety is an integral approach of the traffic system consisting of 'human', 'vehicle', and 'road'. Road and vehicle should be tuned to a person's capabilities, and must provide protection. Education must prepare a person for his traffic task, and finally it should be checked if he participates in traffic safely. Sustainable Safety, therefore, is not just 'infrastructure'.
Sustainable Safety aims at road safety measures that intervene as early as possible in the 'chain' from system design to, ultimately, traffic behaviour. This is necessary because it is the gaps in the traffic system that lead to unsafe behaviour, such as errors and offences, which can eventually result in crashes. By intervening in the system as early as possible, unsafe actions are made minimally dependent on the individual road user's choices.
The five Sustainable Safety principles
Sustainable Safety now has five main principles:
Functionality of roads,
Homogeneity of mass, speed, and direction,
Recognizability of the road design and predictability of the road course and road user behaviour,
Forgivingness of the environment (physical) and between road users (social),
State awareness by the road user.
The last two principles have been added to the Sustainable Safety vision in the 2005 update.
These five principles are based on scientific theories from road engineering, biomechanics, and psychology. They are explained in more detail in the book "Advancing Sustainable Safety" and have been detailed for the areas of: infrastructure, vehicles, intelligent transport systems, education, and regulations and enforcement. The principles have also been worked out for specific subjects and target groups: speeds, alcohol and drugs, the young, cyclists, pedestrians, motorized two-wheelers, and freight transport.
Functionality
A sustainably safe road network has a functional layout, based on three main road types. The two most 'extreme' types are, respectively, main roads, for traffic dispersion, and access roads, for access to the destination. The third type, the distributor roads, forms a link between the other two types, both literally and figuratively.
Homogeneity
Sustainable Safety aims at homogeneity in mass, speed, and direction. This means that vehicles with large differences in mass, speed, and direction must be physically separated from each other. For example, cars and vulnerable road users are incompatible, and so are lorries and other vehicles, or motor vehicles driving in opposite directions. Conflicts between these vehicle types will almost inevitably have a severe outcome. With separate infrastructures or dual carriageways this type of conflict can be prevented.
Where physical separation is not possible, for example at grade level junctions, the speed must be reduced. It should be sufficiently low that all possible conflicts will end safely, i.e. without any severe consequences. Measures that can be used here are lowering of the speed limit and speed reduction, for instance by constructing roundabouts or raised junctions and raised pedestrian crossings.
Recognizability
Road users should know which driving behaviour is expected of them and what they can expect from others. In a sustainably safe traffic system, road users should 'automatically' drive as is to be expected. Generally, people make fewer mistakes when engaging in automatic behaviour, than while driving using reasoned actions.
The desired driving behaviour can only be incited with a uniform road design which is well tuned to it. Drivers need to recognize the road type and automatically behave accordingly. This must be the case for the entire road network: not only the other road users' driving behaviour should be predictable, but the road course as well.
Forgivingness
Forgivingness in the physical sense means that the road design ensures that the outcome of any possible crashes is as favourable as possible. A vehicle that goes off the road should not hit any obstacles or fixed objects, because this can result in severe injury. The vehicle itself should offer protection to both its occupants and to the collision opponent.
Forgivingness in Sustainable Safety also has a social meaning. Through anticipatory behaviour, the more competent road users should provide more space for the less competent road users. This will prevent errors made by the latter group being 'punished' with a collision.
State awareness
State awareness refers to the road user's capacity, or the opportunity, to correctly judge his own fitness to drive. This means that he must know which skills he possesses and whether they are sufficient to drive safely. But road users should also be capable of knowing if they are, temporarily, unfit to drive due to alcohol, stress etc.
When the foundations for Sustainable Safety were laid in 1992, the necessary preparations were made for implementation of the vision. In 1995, this resulted in the start of four Sustainable Safety demonstration projects. The experience gained here, contributed to the covenant Start-up programme Sustainable Safety in 1997. This covenant included agreements about a package of road safety measures and the intention of making policy agreements for a second phase of Sustainable Safety.
In addition to the measures in the Start-up programme, other measures that fitted well within Sustainable Safety were taken during the 1990-2005 period (and sometimes even earlier). An example is the construction of roundabouts.
Sustainable Safety demonstration projects
For the initial period of Sustainable Safety, in the mid 1990s, four areas in the Netherlands were designated as Sustainable Safety demonstration projects.
The areas were selected based on their location in the country, the nature of the proposed measures, the traffic problems in the area, and the organizational and financial aspects and the aspects as regards contents of the submitted plans.
The development of knowledge and its dispersion were particularly important for the demonstrative nature of the projects. The process and the effects of these demonstration projects were monitored by consultancy companies.
Start-up programme Sustainable Safety
In 1997 the Start-up programme Sustainable Safety covenant was signed. It involved agreements between the Association of Netherlands Municipalities, the Association of the Provinces of the Netherlands, the Ministry of Transport, and the Association of Water Boards. It contained 24 road safety measures which could be implemented relatively quickly, and the intention of making policy agreements for a consecutive phase of Sustainable Safety after the Start-up programme had been completed – then planned for 2001. In order to complete the implementation of a number of measures, the Start-up programme was extended to 2003.
Contents of the Start-up programme
The measures from the Start-up programme that could be implemented relatively quickly were mainly measures to adapt the infrastructure and several behavioural measures:
make a distinction between major roads and low-traffic areas,
a plan of action for an urban 30 km/h speed limit,
extension of urban 30 km/h zones,
extension of rural 60 km/h zones,
priority on major roads,
uniform priority regulation on roundabouts,
mopeds on the carriageway,
priority for (light) mopeds and cyclists coming from the right.
By the end of the Start-up programme, each road authority was supposed to have categorized its road network according to the CROW requirements. This was partially subsidized by the government.
The idea was a considerable increase of the number of 30 km/h zones. To encourage this, the road authorities were allowed to use what was known as a 'sober layout'.
The Start-up programme also included measures for finance, enforcement, education, and communication. For these measures no subsidy was available.
Second phase of Sustainable Safety
Initially, the second phase was included in the National Traffic and Transport Plan in the form of a number of specific agreements between managerial parties: the Ministry of Transport, the Association of the Provinces of the Netherlands, the Framework Act areas, the Association of Netherlands Municipalities, and the Association of Water Boards. Because the National Traffic and Transport Plan was not approved by parliament, the main points have found their way into the Mobility Paper which results in more binding agreements than a covenant.
