Multi-Criteria Life-Cycle Assessment of Local Public Transport fleets renewal

Among the strategies to achieve the goal of transport decarbonization, national and local government have been funding the renewal of local public transport (LPT) fleet through either the acquisition of new clean vehicles or the introduction of advanced clean (bio-)fuels. In order to optimize the investment over time and avoid undesirable indirect counter-effects, such policies need to be assessed ex ante and duly planned. In this paper, a methodology based on a life-cycle assessment of (investment, maintenance and operating) costs and (global and local) environmental impacts is proposed to identify suitable pathways for renewal of the existing bus fleet, in the medium and long term. Using a multicriteria decision matrix, different a-priori scenarios are compared, seeking for non-dominated ones with respect to financial and environmental sustainability criteria. The methodology has been applied to the case of the Como, Lecco, and Varese provinces (with about 860 operating buses, almost all equipped with diesel engines and operating in both the urban and the ex-urban context). In the urban context, the study has shown that the “full-battery-electric” scenario has the lowest environmental impact since there are zero tailpipe emissions and greenhouse gases are lower than all the other transition scenarios. For the ex-urban service (characterized by medium- and long-distance routes), a “full-battery-electric” scenario is not yet feasible, considering that long-range electric buses having sufficient battery autonomy to guarantee efficient operations in these contexts are not yet widely available. Liquefied natural gas-powered and hybrid electric vehicles would be other options for decarbonising ex-urban LPT, but their life-cycle impacts should be considered with care.