How long will my ‘go-ahead’ remain at the traffic lights, when should I close the doors at the stop and how fast should I drive to get through the next junction without stopping? The driver assistance system ‘COSEL’ has an answer to these and other possible questions from the drivers of buses and trams operated by Dresdner Verkehrsbetriebe (DVB). It is designed to stabilise the timetable, increase passenger comfort and, above all, save energy and therefore money. The system was developed in Dresden, but can also be used in other cities. All DVB trams and around a third of the buses are now equipped with it. The abbreviation ‘COSEL’ stands for ‘Computer optimised speed-control for energy-efficient light-rails’.
‘The driver assistance system is part of a whole catalogue of measures to conserve resources and save energy that we at DVB have been consistently pursuing for years,’ says Head of Operations Alexander Koch. ‘This not only saves energy, but also pure money in times of tight public budgets.’
‘The COSEL project, which was originally launched in 2012 by Dresden University of Technology (TUD), the Dresden Road and Civil Engineering Office and Dresdner Verkehrsbetriebe (DVB), is now ready for series production,’ says DVB project manager Christian Gassel, who has been involved from the very beginning as a TUD employee. And he adds: “At the time, drivers on line 3 were only given a departure recommendation at Nürnberger Platz, but today the number of stops and intersections integrated into the system has increased significantly. Most of them are located on or within the Dresden city ring road. Such a networked system in regular public transport services is the only one of its kind in the world.
A necessary prerequisite for the use of ‘COSEL’ was the equipping of the respective traffic light systems (LSA) with state-of-the-art node computers that can provide all the necessary basic data. In contrast to the early days, when drivers received information on a separate mobile phone display, ‘COSEL’ can now be fed directly into the on-board computers of Dresden’s vehicles. The ongoing development and practical implementation of the driver assistance system, which also involved partners from research and production, began in 2020 and cost around 590,000 euros. A total of 75 per cent of this was funded by the European Regional Development Fund (ERDF), the federal government and the Free State of Saxony. DVB therefore spent around 147,000 euros on implementing the system in the on-board computers.
Thanks to ‘COSEL’, buses and trams have to brake, stop and restart less at junctions. This is not only more pleasant for passengers in the vehicle. It also stabilises the timetable. The information on the display about when to depart or the best speed to arrive at the junction for a ‘go ahead’ is only ever a recommendation. The final decision is made by the driver, who can or even must decide differently depending on the traffic situation. For example, despite a signalled departure recommendation, the driver may sometimes wait if someone else comes running at the stop. If at least the majority of all the recommendations given are adhered to, up to two gigawatt hours of energy can be saved in Dresden’s tram traffic. That would be the equivalent of up to 400,000 euros per year.
DVB has been pursuing projects that conserve resources and utilise them sustainably for many years. The company has been saving around 11 gigawatt hours (GWh) of energy per year by retrofitting the rectifier substations and switching through feed sections since 2010. This corresponds to around 2.2 million euros. Driver training courses on energy-efficient vehicle operation (0.9 GWh) and adjusting the interior temperature in the vehicles (2.7 GWh) have also already been implemented, saving a further EUR 730,000 per year in total. Photovoltaic systems on the roofs of the depots in Trachenberge, Gruna and Reick as well as at Hohenthalplatz almost ensure that the properties are self-sufficient in electricity. Only the traction current for the trams and the charging current for the electric buses have to be supplied separately. Another photovoltaic system will soon be installed at the Gorbitz depot. Further projects such as the optimisation of night-time vehicle parking management at the depots are to follow in 2025. For years, DVB’s experts have succeeded in saving energy and fuel or using sustainable technologies. This is why the Dresden-based company is one of the most energy-efficient public transport providers in the whole of Germany.
(Info: DVB)
20.05.2025
