WITNESS on the Spanish Roads

In this blog Tony Waller discusses how Lanner partner Avantsim have used WITNESS to model road networks and traffic volumes in Valladolid, Spain

Last November I wrote a blog about rail infrastructure modelling in Spain. In this blog I’d like to return to Spain, to the streets of Valladolid and the modelling skills of Alberto Gasco Rodriguez, a senior expert and exponent of simulation from Avantsim Software of Madrid. He has recently developed a system in WITNESS that allows easy evaluation of journeys through road networks with different traffic volumes.

See map view from the model showing the animation of traffic movement above.

The system is easy to set up and use. The key to this is the generic structure of the designer elements that Alberto has created. Each road section is the same structure and populated with data from Excel to add specific characteristics. An example of part of the traffic light definition in Excel is shown below. Other data includes lanes per segment for overtaking, profiles of traffic volumes, speed factors and general traffic behaviours such as turn likelihood at junctions (note that this simplifies a model through not needing to know all individual routes being made).

A table of Traffic light data from the Excel workbook that defines the road network setup

Results show congestion and include specific spread data on journey times, as the example shows below.

A chart showing the variation in journey times along a specific route at different times of day

Over the past ten years I’ve seen many examples of traffic modelling in WITNESS, from new shopping center evaluations in Australian cities to very detailed single junction models in the Czech Republic. All have been very successful and have enabled planners to make the right decisions.

It is interesting to note the variation in levels of detail of such models. In this area of modelling it is clear to see the choices in granularity of modelling that can be chosen – for example the size of vehicles - for many models a generic size is perfect for the evaluations needed. Another example is that of speed. Some models demand a full data set of propensities to travel different speeds whereas for other models this may not be needed e.g. where speed is largely dictated by road speed limits and traffic lights, etc. The art of simulation is to understand these simplifications of reality and know what to include and what is simply adding modelling time.

Alberto has developed a useful system at an appropriate level of detail, one that is easy to set up and use, therefore it WILL be used - which is what Valladolid (and the world) needs!

Please contact Alberto if you’d like to share any views or ask any questions about his experiences in this type of modelling by leaving a comment here on this blog.