Digital Twin for Sarajevo

In order to better understand Sarajevo, Hubert Klumpner's professorship, led by post-doc Michael Walczak's research group, has designed the first computer-aided 4D model for the city and canton of Sarajevo. It combines quantitative and qualitative data to make complex planning decisions. Researchers in Sarajevo collected the data for this city's first Digital Twin using a mobile laboratory called “Studio Mobil”.

The result is a “digital urban imaginarium” of the built and natural environment. It contains information on infrastructure, mobility, energy, water, air and soil quality, but also on people's behavior and demographics. “In order to be able to map the complexity of the city, we need new methods, processes and technologies,” says Klumpner.

The Digital Twin connects different scales and takes topography, climate, every building and every vehicle into account. The model depicts energy consumption at any time of the day and night in order to be able to represent the behavior of people in the city. They are depicted as “agents” in the model with the help of machine learning algorithms. In this way, the simulation can understand how individual people move, where they live, and how they work.

The digital twin includes the built and natural environment, but also social scientific data such as the diverse cultural, ethnic and religious characteristics of different neighborhoods. In addition to the spatial dimension, the multidimensional plan takes into account the temporal dimension in urban planning. For example, every single second of traffic behavior can be tracked and visualized in real time.

The researchers do not blindly trust the digital data; the simulations were checked and calibrated on site. The “Studio Mobil” was present at strategic locations in the nine city districts for public hearings. At the same time, a cartography of wind movements was created and traffic behavior was recorded. In this way, research combines quantitative and qualitative data and empowers the population in the process. “We are not planning a smart city, we are working with smart people on the future of their city,” says Klumpner.

Until now, the city was thought of as a linear structure along a one-way street in a river valley. The new master plan describes the urban development around the city hill as a green heart. It focuses on the cross-relationships in the valley and also takes into account the hillside settlements, where 40 percent of the population lives. Sarajevo is currently one of the ten cities in the world with the worst air quality. The plan calls for non-fossil energy sources for transport and heating. In addition, the forest areas should be protected and regenerated in order to improve the air quality in the city.

The cantonal planning office is already using the Digital Twin to implement alternative urban planning. The digital model is not a fixed plan, but a planning tool for decision-making. It links various parameters and thus reflects the complexity of an urban structure. And with the twin, planners can simulate scenarios and see how, for example, a new road will affect traffic flow or air quality.

The Digital Twin was the basis for public hearings, which are required by law for planning in Bosnia and Herzegovina and which took place until the end of April. The researchers speak of “bottom-up simulations”. To make the Digital Twin more accessible, they built a physical model of the city overlaid with projections. A web-based model allowed people to participate remotely. Some key locations in the city were animated on a 1:1 scale in order to convey them clearly.

The events took place in all nine municipalities of Sarajevo, and their input is now being incorporated into the model. An accompanying exhibition is currently touring the six Western Balkan states and will be on display at the Museum of Applied Arts in Belgrade from February 2025.

In 1984 the Winter Olympics took place in Sarajevo. The war raged from 1992 to 1995. Today, almost 30 years later, the city has changed. At the end of April, 18 mayors from Ukraine visited Sarajevo to find out how a city can reinvent itself after a state of war - supported with new digital planning tools.