Abstract Summary
Despite its relatively small size, Luxembourg City is facing major challenges in terms of traffic congestion (33h/person/year spent in traffic congestion according to the INRIX 2017 Global Traffic Scorecard), primarily caused by an important share of cross-border commuters driving more than 35km on average for home-work trips, and the highest car ownership rate in the European Union (0.75 vehicles/person). With the goal of reducing the car pressure and promote sustainable mobility, the country is heavily investing on public transport (PT) and in particular on new technologies that enable smart and cleaner transport. Three trends towards next generation PT systems are observed: 1) introduction of greener vehicles such as electric/hybrid buses (e-buses), 2) focus on high service quality (e.g. increased ride comfort via mitigation of stop-and-go driving) and 3) reduction of emissions and bus operating costs related to fuel/energy consumption and equipment wear and tear. In addition, the digital revolution is offering new opportunities to empower vehicles with new Information and Communication Technologies enabling the adoption of Cooperative Intelligent Transportation Systems (C-ITS) and new ways of managing the system in a more efficient way. These trends however bring new challenges. The first challenge is posed by different operational characteristics and constraints of e-buses, e.g. they need to periodically recharge batteries at e-charging stations placed in selected stops and terminals. This brings additional complexity into PT operations since charging may have an impact on line scheduling. The second challenge, relating trends 2 and 3, is how to provide comfort- and cost-related benefits without negatively impacting general traffic performance. Relying solely on strategies such as Transit Signal Priority (TSP), which prioritizes PT vehicles at signalized intersections, might cause congestion effects that could backfire on the PT system itself. In this study we argue that we can make better use of e-buses and the C-ITS paradigm by introducing new strategies explicitly optimizing the interactions within the PT ecosystem components consisting of PT vehicles, traffic signals, and electric bus charging infrastructure. The main novelty of eCoBus is that these strategies combine cooperation and negotiation within the whole PT ecosystem, enabled by C-ITS connectivity. The main research challenges are in formulating and solving complex optimization problems to manage the fleet at the planning phase, while developing novel real-time control strategies to better manage the vehicles at the operational phase. The proposed system is tested and evaluated in large-scale simulations and in real-world controlled experiments supported by our PT industry partners—Volvo Buses and Sales-Lentz (PT operator).
