eCoBus aims to design a system exploiting the potentials of the Cooperative Intelligent Transportation Systems (C-ITS) to increase operating efficiency and comfort of next generation urban Public Transport (PT) systems. The core of such systems is composed of hybrid/electric buses and trams. The project is a research activity supported by the initiative of Ministries of Economy, Sustainable Development, Volvo Buses, and Sales-Lentz to create in Luxembourg a test arena for sustainable public transport system.
Background: The fundamental role of Public Transport (PT) for sustainable cities motivates continuous investments in smart, efficient, users-centred and environmental-friendly solutions. Luxembourg is one of the countries in Europe that is prioritising investments on future PT systems: a complex combination of conventional vehicles (trams, diesel buses) is being complemented with latest technology hybrid-electric and electric buses (ebuses), which will allow deploying zero-emission zones in the CBD. All these investments are done within a vision towards the Smart City paradigm, where all transport means will communicate and cooperate for constantly improving the overall quality of services.
Challenges: A large-scale electrification of the system will require the installation of on-route charging stations to extend range, reduce battery costs and distribute the energy demand in time and space. It is clear, on the other hand, that such facilities will put considerable stress on the energy distribution infrastructure, and will come with a cost for the PT service providers. Clearly, an effective strategy for the PT operator is to plan the use of charging infrastructure in a distributed way in time and space to minimise total charges and reduce operating costs.
Moreover, additional savings can be made by reduction of energy use in operations by minimising bus speed variations due to interaction with traffic (via dedicated lanes) and with the infrastructure (via preferential treatment provided by traffic signals). However, strongly prioritising PT over car traffic may not always be a good solution, as congestion may propagate and cause blocking back issues onto the same PT services.
Our approach: In this project we will develop innovative control algorithms exploring the potentials of cooperation and negotiation of the entire PT mobility eco system. We develop a C-ITS-empowered system approach that takes into account specific e-bus objectives (reduced energy use and efficient recharging) together with those of conventionally fuelled vehicles (reduced consumption and emissions). Economic and environmental goals are integrated with the required objectives of service efficiency, including passenger comfort.
Project’s innovation: Standalone control systems distributed between stationary infrastructure and PT vehicles are in this project extended with new capabilities and transformed into a single energy-aware cooperative entity. Consequently, previously independent control domains aiming at limited set of objectives now negotiate solutions satisfying multiple, often conflicting performance objectives of the emerging PT systems.
Research contributions: Optimising such a complex system will require framing within a game-theoretical approach, as multiple actors having multiple goals will have to be aligned towards common optimal strategies. In addition, planned services and charging strategies should exhibit robustness with respect to the stochastic nature of the system, especially due to the interaction with traffic controls, which are in turn depending on the variability of traffic. Such a system justifies the appeal of employing C-ITS as short-range communication media, but then calls for novel computational approaches. Our goal is not just to allow operating buses within schedule/headway constraints, but also looking at the energy consumption, while respecting passengers’ comfort. To achieve this, we expand the PT mobility ecosystem by redesigning and integrating the existing control systems through the addition of the C-ITS layer and by developing new support services. Novel negotiation-based cooperation of control elements at traffic infrastructure (signal control with Transit Signal Priorities) and in-vehicle Cooperative Driver Assistance Systems will be introduced.
The application of C-ITS to PT also advances the research towards the fully automated PT systems of the future.