In Gothenburg, Vägverket - the Swedish Road Administration (SRA) - currently has four major tunnels in operation: the Göta, Gnistäng, Tingstad and Lundby tunnels. The Traffic Information Centre (TIC) in Gothenburg, run by the SRA, monitors the tunnels 24 hours a day, seven days a week. The total length of the tunnels is four kilometres, with the longest being just over 2,000 metres. The Tingstad tunnel is among the two most trafficked sites in Sweden with approximately 120,000 daily vehicles and this figure is steadily rising each year. Plans for other tunnels are also being made, both within Gothenburg and also in other parts of the TIC area.
Fire safety drills
In December 2002, there was an incident where a car caught fire in one of the tunnels. This clearly showed the importance of maintaining and updating the routines and checklists for the tunnels, since during the incident weaknesses were observed.
The SRA Western Region realised that a new concept for tunnel safety was needed, and started to develop a new training package where the use of large-scale simulated exercises were to be large parts. The specifications of an advanced tunnel monitoring simulator were developed, as were the first plans for performing real fire exercises. Much of the inspiration for a simulator came from the way air traffic controllers are trained in Sweden, an area where simulators have been in use for decades, providing advanced training to air traffic controllers from all over the world.
The first in a planned series of live tunnel exercises was carried out in the autumn of 2003 by the SRA. The Lundby tunnel was chosen for the exercise which aimed at studying what happens during the crucial first minutes of a car fire in the tunnel. Each year a different tunnel is used so that all tunnels will be evaluated regularly. The exercises are always made in close cooperation with the Gothenburg police and fire brigade.
The exercise revealed the importance of taking the correct measures during the first few minutes after an accident. These can include controlling smoke ventilation and barrier systems at the entrance of the tunnel and coordinating with the emergency services. The results of the fire exercise showed that the situation can worsen by starting the fans at the wrong moment. The oxygen added to the fire makes the heat intense and smoke quickly starts spreading from the top half of the tunnel to finally completely cover the bottom as well. Anybody trapped in the smoke would suffocate to death.
After an exercise, the results are gathered and evaluated. However, there are drawbacks with using live exercises. They have an influence on the traffic, since the tunnel used will be shut down or heavily restricted before, during and after the exercise. This naturally has disruptive effects on both commercial and ordinary road traffic. They also cost a lot of money and their planning takes many months to complete and a lot of staff is involved during the exercise. Also, a live exercise is not as dynamic as one might wish because it is difficult to carry out a series of events simulating an incident and these events are perhaps not as real as one might think.
Training simulator
The tunnel simulator, which has been in operation since summer 2004, is an important training instrument to create realistic conditions so that the operators can handle such situations even better. With the simulator, SRA can maintain a high level of staff competence without causing disruptions to traffic that usually result from major exercises in tunnels. Providing useful, cost-effective training is one of the major goals of the training concept.
The simulator is also used to evaluate existing routines and checklists for the Gothenburg tunnels. SRA can execute scenarios that would be too complex to deal with in a live exercise. Errors and weak spots in the routines can hence be found before they have an actual impact in the real world. Obviously not only errors can be caught but also more effective ways of working can be evaluated.
For new tunnels, routines can also be developed and tested before they enter in service so that operators will be well prepared. In all new tunnel projects in the future, implementation of the tunnel management application into the simulator will be mandatory. The simulated tunnel environment went in use two months before the opening of Gothenburg’s latest tunnel, the Göta tunnel. This gave traffic managers plenty of time to get used to the new system and be well prepared for the opening.
The simulator is also used for training new operators to help teach them how the tunnel monitoring application works before they get to operate in the real world. They must be familiar with their tools before they sit down in position.
How does it work?
The SRA Western Region’s simulator comprises five computers that cooperate. A suite of proprietary applications and retail software gives the operator the impression of real traffic and real events from all barriers, VMS signs, lane signals and other hardware.
The operator applications and the core of the simulator are run from one computer (CSS simulator). The graphic interface is identical to the one used in his everyday work. The operator controls every aspect of the tunnel from this environment. He can then train events like re-routing traffic in case of an emergency or closing down traffic lanes due to maintenance.
iFIX software has been implemented since spring 2007 for the tunnel control system. The real SCADA systems run on separate servers using iFIX and the simulator core fools the SCADAs to believe that real hardware exists by faking them and their responses. The Central Steering System (CSS), as the operator application is called, connects to the SCADAs just like in the real environment.
All events in CSS, both operator and system generated, are monitored and recorded by the simulator. When they occur they are immediately sent over the network to the next computer through the Paramics system. For example, an event could be an operator setting a speed restriction or ordering a barrier to be lowered.
Proprietary integration software enables communication with the other servers but primarily with the Paramics model. XML documents are sent over TCP for all communication. These documents contain information about hardware status and any changes to these. The computer running the Paramics model is dedicated to generate vehicles and their movements. To accomplish this Paramics, Quadstone version 5.1 is used.
The documents received from the CSS simulator are interpreted, their impact on traffic is considered and the results are communicated to the Paramics model so that traffic is changed or affected accordingly. The relevant documents are then forwarded to the visualisation model for display on the monitors. Events like queues or stopped vehicles are discovered in Paramics and when they do, notifications are sent back to CSS. CSS then generate an alert which is viewable by the operator. This enables simulation of real alerts based on events in the simulated traffic as well.
Vehicle and traffic simulation is displayed on screen enabling the simulator to be fully useful. Orders from the operator, such as speed restrictions, closed lanes, etc. affect the simulated traffic displayed to the operator. Incoming XML documents from the Paramics model are received constantly by the 3D application. When vehicle positions are intercepted the model moves the vehicles to their new position which gives the effect of a real traffic flow to the operators. This realistic effect is accomplished since these positions are received at least ten times a second providing the flow to be smooth and natural.
The tunnel and its vicinity are built as a model using a 3D modelling tool so that a virtual version of the tunnel is created. The model is then filled with vehicles generated by the Paramics model. This makes it possible to create a realistic traffic environment that fully benefits from SRA’s experience of Paramics software.
Training sessions
A proprietary client software is used to create the training sessions. This software can be installed on any client running Windows. It connects to the CSS simulator core over the network and trainers and administrators can execute various tasks.
Standard drag-and-drop features of Windows enable the instructor to create realistic and demanding scenarios for the trainee. Events are then dragged to the timeline so that the instructor can build the scenario easily.
All scenarios can be saved and each can be the base for new training sessions. One can also combine scenarios to a single session giving infinite possibilities to build the training. A library of scenarios has been developed from which the instructor can do a selection. The library is constantly evaluated so that new incidents are inserted when necessary.
The instructor can also change the course of events during the training session using the same application. Situations and events can be added or removed when the instructor monitors an exercise. This gives the benefit of being able to have a different dynamic scenario every time, so that the trainee never quite knows what to expect from the session.
A training session starts with the instructor giving the background and goals of the session. After that, the trainee can log to the simulator and start the training session. Self-paced trainings are performed by the trainee himself and when finished he reports back to the instructor. A more complex session is monitored by an instructor. Afterwards the instructor and the trainee evaluate it. If necessary, the session is repeated another day until both the trainee and instructor agree that the goals have been achieved.
In Sweden, all traffic managers and operators receive a common national training. This mandatory training takes about 14 days to complete. After this training, regional training in the Gothenburg area takes place. Managers learn how to handle the local systems and the local road network. During this period, real life training with another traffic manager is combined with simulator training. At the end of 2006, all operators were certified and now use training as a part of their normal working routine.
Other advantages
This Swedish advanced training simulator has other advantages. For example, it can be used for validation of a new tunnel design, during the blueprint level of designing. By modelling the tunnel in 3D and connecting it to a traffic model, it is possible to get a very realistic view of how the tunnel would look like. The traffic flow and behaviours could be very close to reality giving input both to construction and traffic management teams early on.
This could be direct input to the architects and traffic planners so that the position of signs, barriers, VMS signs and other hardware could be evaluated long before they are physically installed in their positions. It is always more cost effective to find errors and anomalies early on than it is to find them during later development phases. 31/07.
Thanks to Peter Wegen of the Swedish Road Administration and Joaquim Rossberg of Kwow IT, Gothenburg.
