Ventilation control in the Blanka tunnel, Prague

Realization: 2014

Mathematical modeling

We developed detailed mathematical models of airflow dynamics, traffic and pollution concentration for the Blanka tunnel complex consisting of several connected ramps (entrances and exits). These models allow to simulate traffic conditions, airflow velocity and air quality inside the tunnel and test the behavior of the tunnel under unexpected situations such as congestions.

Using these models, we supported the design of the ventilation system of the Blanka tunnel complex (satisfactory number of jet fans, power of ventilation shafts, suitable placement of ventilation devices, etc.).

Fire ventilation

For the fire ventilation purpose, we developed a systematic approach for airflow velocity control design. We use PID controllers for airflow velocity control during fire situations. Our approach was successfully verified during this project where the design of airflow velocity control is a challenging task, since the Blanka tunnel complex is divided into more than one hundred fire sections, and the PID controllers must be tuned for each section.

Our approach saves much time with the controller tuning within complex testing and the controllers can be tuned already during the design stage of the tunnel.

Operational ventilation

We developed the optimal control strategy for operational ventilation in road tunnels. In the Blanka tunnel complex, there are complex requirements on indoor and ambient environment of the tunnel and tens of ventilation devices to be controlled. Our control strategy ensures prescribed conditions on the air quality while being energy efficient. It uses the mathematical model of airflow dynamics and its main advantages are: fault tolerant control (robust against sensor errors and jet fans failure), energy savings (startup of ventilation devices in the most efficient way) and improvement of environmental quality (both inside and outside of the tunnel).


The Blanka tunnel complex is a part of the Prague City Ring Road and the largest road tunnel in the Czech Republic with the total length of more than 5 km. It was open to traffic in September 2015. It consists of three tunnels, which are connected through tunnel ramps (entrances and exits). The average traffic intensity in the tunnel complex is 60 000 vehicles per day.