A plug-in hybrid electric bus fleet as a rational and sustainable urban transport policy: a real casa application in Italy

Urban sustainability, green development and sustainable mobility are based on the achievement of three goals: environment, society and economy. This means that a sustainable planning must be, at the same time, equitable, viable, and bearable. In metropolitan areas, the transport sector impact with respect to both fuel consumption and environmental emissions. At this aim, planning policies aimed at reducing these negative impacts are very important. Many researches cover the problem of perform rational decisions to improve the transportation sector. A rational decision means acting in the best possible way considering the goals and constraints. Starting from these considerations the aim of this paper was investigated the energy and environmental implications deriving from the renewing of public transport bus fleet to both electric and diesel plug-in hybrid vehicles. The case study was the city of Salerno in Italy. Results of the estimation show that the renewing the 30% of the bus fleet into electric vehicles will produce significant positive environmental impacts, but the high investment costs suggest that this policy is not “eco-rational” for the city because of it is not economically convenient form a cost-benefit point of view. By contrast, the renewing of a percentage of the bus fleet into a diesel plug-in hybrid electric vehicle will produce comparable environmental impacts to those estimated for the previous design scenario, but in this case also the economical sustainability was verified with an investment payback period equal to 10 years.