Renewing Bus Fleet into Diesel Plug-in Hybrid Electric Vehicles: Environmental Implications in a Medium-Size City in Italy

In urban and metropolitan area, the transport sector significantly contributes in terms of both fuel consumption and pollutant emissions. In this context the ex-ante evaluation (through quantitative methods) and the implementation of sustainable policies must be a central aim for urban mobility. Many papers deal with the importance to take rational decisions to improve the transportation system (.eg. Cascetta et al., 2015). The idea of this paper is to propose an ECO-rational transportation planning, that means acting in the best possible way considering the men’s health and the environment’s benefits (ECO-logocal) and are sustainable for an economic point of view (ECO-nomical). Starting from this definition, the question proposed is: are the so called “common” sustainable transport policies always eco-rational? For example the renewal of vehicle fleet; the use of light goods vehicles for urban distribution, the introduction of a restricted area in the city center, are always rational interventions? In this research I have tried to partially answered to this question, estimating the environmental impacts of using electric and/or plug-in hybrid electric vehicles for renewing the bus fleet for public transport services in an Italian medium size city. Results of the estimation show that updating (renewing) the 30% of the Salerno public transport bus fleet into electric vehicles the fuel consumption and the equivalent CO2 emissions will reduced to-7.2%, while the PM10 will reduced up to-10.0%. By contrast, from an economical point of view, the high acquisition cost for electric buses and the inefficiencies deriving from the low autonomy of the batteries suggest that this scenario is not “eco-rational”. The simulation results deriving from the renewing a percentage of the bus fleet into a diesel plug-in hybrid electric vehicles show comparable environmental impacts (scenario with bus equipped with two batteries for a double autonomy) and is economically sustainable with an investment cost of 4.8 millions of Euro and a payback period of about 10 years. © 2015, World Scientific and Engineering Academy and Society. All rights reserved.