Traffic researcher Harald Frey examines the feasibility of super blocks in the city of Salzburg. The traffic calming concept from Barcelona can also work in small towns.
The traffic researcher Harald Frey from the Technical University of Vienna has created a mobility strategy for the city of Salzburg on 110 pages. The concept, which was published in March last year, was commissioned by the Salzburg Green Party and the Citizens’ List. In addition to countless measures to optimize bicycle, pedestrian and public transport, the study also includes the unusual idea of establishing so-called super blocks in the Salzburg city area, as is known from Barcelona and other metropolises.
Mr. Frey, what are superblocks? Harold Frey: The basic principle of the superblocks states that the path grid for pedestrian and bicycle traffic actually has to be tighter than for car traffic. The idea originally came from Barcelona’s grid system. The basic statement is that there is no need for a lane for motor vehicle traffic every 60 or 70 meters, but rather a close-meshed primary network for pedestrians and cyclists. A round 400 x 400 meter grid is sufficient for motorized traffic, while the network of paths in between should be designed primarily to be attractive to people. It is important, of course, that there is still access for residents and delivery traffic, which is to be used temporarily and at pedestrian speed. The most problematic element of using public space – namely parking – is prohibited. That’s the basic principle, so to speak. The access points to public transport are optimally located at the edge of this super block.
Does this mean that super blocks are not to be equated per se with strict driving bans in certain areas, but the primary aim is to avoid through traffic? I agree. In addition, there are also phases or stages of implementation and different intensities. The simplest and most logical means is to stop through traffic. Ideally, the next steps are to reduce the number of parking spaces in public spaces, more surfaces for cyclists and pedestrians, and greening measures. Or then to create completely car-free sections or to increase spaces in front of schools or other facilities. These are the measures that also play a role, but which cannot always be implemented with full intensity. Each superblock is different, it depends on the features. For example, is there a doctor or a pharmacy on site? And in Barcelona as well as in Vienna and elsewhere, the discussion about parking spaces is of course the most emotional. Of course, there are quite a few areas that can be used for other things. The Superblock model has different levels and is also flexible in terms of the intensity of the measures.
Does that mean that different measures can be adapted over different periods of time for the respective location? Absolutely correct. Measures were also simply tested over a certain period of time in Barcelona. For example, so-called diagonal barriers, which mean that you cannot drive straight across an intersection, but have to turn and thus be guided out of the block area. These are measures that you can use to feel your way forward quite easily during implementation.
In Barcelona, the aim of the super blocks was apparently not primarily to reduce car traffic, but to improve air quality and the quality of life of residents in the affected areas. The reduction in car traffic is basically just a by-product. The point is that over time you will realize that many short distances can be covered much more comfortably on foot or by bike than by private car thanks to the measures mentioned. This can of course trigger a certain publishing shift. Repressions are always a hotly debated topic. It is often expected that car traffic will simply be shifted outwards one-to-one as a result of the measures taken inside. It has to be said that superblocks can only be one building block of an overall concept for urban mobility. The interaction of the various measures then demonstrably increases the proportion of car traffic in a city.
Barcelona is always cited as a prime example when it comes to superblocks. Are there already tangible results for this city? Yes, there are. After a short time you can already see a significant reduction in the emission values in the respective areas. Specifically, two larger super blocks were examined, in the area of which pedestrian traffic increased by 10 percent and bicycle traffic by 30 percent over a period of five years, while in one of the areas car traffic in the greater area around the super block decreased by 26 percent. Inside, there were even 40 percent fewer cars on the road. There was also a notable shift in traffic in the peripheral areas. In general, our studies have shown that the savings potential when driving a car is up to 14 percent in the short term and up to 22 percent in the long term.
Trials with the Superblocks model are also being carried out in Vienna under the name “Supergrätzl Favoriten”. What is the current status there? One is here in the concrete planning of the implementation. The very laborious and lengthy traffic negotiations with the administration are currently underway. It’s about details, such as the question of whether road markings or plant troughs are used for the design and what the road traffic regulations allow in detail. Of course, one tries to use elements that are as innovative and sensible as possible, which is not always easy given the often very rigid authorities. In any case, there is a clear commitment from all sides to the implementation in Vienna favorites. That would only be a smaller area, but at the same time a big step, in which important insights for the planned campaign can be gained. You will hardly notice any major changes in the overall transport system as a result of this encounter. But it is important to go through the implementation process with all its details once, in order to be able to scale later.
In small towns like Salzburg, some of the basic requirements for superblock concepts are missing, for example the typical rectangular street grid. Nevertheless, the model can be found in the “Mobility Strategy 2021+” you created. Precisely because the idea of the super block can be adapted extremely easily, quickly and flexibly to the respective requirements, it is also suitable for cities like Salzburg. Simple measures such as the diagonal barriers mentioned above can be implemented relatively easily and with little effort, for example in the planned Lasserstrasse/Franz-Josef-Strasse super block. Of course, we also spent a while looking for something suitable in Salzburg. But then we realized that there are some areas in Liefering in particular that already have the character of superblocks and are structurally suitable for this. The approach was to search for areas that were as homogeneous as possible, in which the quality of stay could be massively improved by small measures such as the interruption of a single thoroughfare.
Is there still potential in Salzburg? In some cases, there are already larger contiguous new development areas, which of course do not always measure the formal 400 by 400 meters, but are also criss-crossed with footpaths on the inside. There are also examples in Salzburg that show that you don’t need a roadway six meters wide for every single building. With the help of an in-depth study, further potential is guaranteed to be found.