autoregion international - Ausgabe 1/2021

13 Technology (LIST) teamed up in 2017 with in- ternational academic and industrial partners (e.g., Volvo E-Bus Competence Center, Sales- Lentz) to assess the opportunities and tackle the challenges brought by electrification and connectivity in bus systems. Thanks to the FNR-CORE funded project eCoBus (C16/ IS/11349329), the research investigated the technical and economic feasibility of large- scale introduction of electrical buses, and the added value of data exchange and com- munication between all actors in the whole ecosystem (vehicles, charging and control infrastructure) for optimal planning and management. The eCoBus project contributed to improv- ing the knowledge of next generation public transport systems in three ways: fleet and energymanagement, operationsmanagement and control, and simulation and demonstra- tion in realistic scenarios. Concerning the planning aspects, the main questions driving the research were on the technical and cost-effective utilisation via- bility of e-buses. Despite the political sup- port of replacing conventionally fuelled with zero-emission vehicles, there will be a long transition period where a mixed fleet will be utilised. In fact, full electrification may re- quire important additional investments in the energy support infrastructure, since the cur- rent systems capacities are challenged by the charging power requested by the batteries installed in the buses. Moreover, despite new solutions which can recharge a bus in a mat- ter of minutes (opportunity charging) or even seconds (flash charging), overnight charging still remains a preference for the operators due to the lower energy costs. Nevertheless, the autonomy of buses does not allow full day operation without being recharged. The project addressed the issue of integrating the assignment and dispatching of the vehicles with charging times, and it studied different penetration rates for full electrical and hybrid buses. Through the application of mathemat- ical models that allow solving complex combi- natorial and highly constrained problems, an optimal mix fleet in relation to the number of charging terminals and lines could be recom- mended. By using different lines in the Lux- embourg City network, where e-buses are already used, we could demonstrate that a mix of around 40 to 60% e-buses is optimal in terms of operational costs. To fully meet the requirements of electrified public transport, and offer high service qual- ity to the passengers, apart from choosing the right fleet mix, each vehicle must be operated and managed optimally. This means not only avoiding delays and keeping high operational speeds, but also maintaining line regularity and punctuality, allowing efficient transfers, and reducing the number of unnecessary stops at intersections. Thanks to the Coopera- tive Intelligent Transportation Systems (C-ITS) paradigm, new control strategies could be in- troduced. New communication technologies allow monitoring of the progress of the buses in real time, sendind messages about their per- formancewith respect to the ideal trajectories, and also informing them about the state of the traffic lights. This way, drivers can mod- ify vehicles’ speeds or wait for longer times at stops, hence allowing more passengers to board, avoiding stopping at a red, and above all, preserving regular distances between buses, avoiding bus bunching. We used line 16 connecting Findel with the Central station to assess the gains in terms of service quality, showing that by using the newly developed real-time control strategies we could improve bus operations and reduce the need for sig- nal priorities, which often reduce the overall capacity of the network and cause additional congestion issues. Finally, the eCoBus project successfully demonstrated the impact of the fully inte- grated system of management solutions in a comprehensive and realistic simulation en- vironment, using the widely deployed SUMO (Simulation of Urban MObility) software, which allows a detailed representation of each vehicle and the relevant characteristics in terms of motion, technology, driving be- haviour, and an accurate interaction with all other actors in the transport system (cars, pedestrians, etc.). The whole Belval area, in- cluding the surrounding residential zones was implemented and used to evaluate the results of the eCoBus research in a set of controlled experiments. This simulation will be also the starting point for follow up research, which will aim at further exploring the opportuni- ties of automation and on-demand mobility, aspects that were not covered in the eCoBus project, but that will form equally important building blocks for smart and sustainable mo- bility, the ambitious scenario that Luxembourg aims to develop in the next decade. Francesco Viti Associate Professor, MobiLab Transport Research Group Faculty of Science, Technology and Medicine Digital BusinessCard MobiLab https://mobilab.lu UNIVERSITÉ DU LUXEMBOURG www.uni.lu

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