Buses account for almost 60% of the total public transport services in Europe, and most of the vehicles are diesel fuelled. Regional transport administrators, under pressure by governments to introduce zero-emission buses, require analytical tools for identifying optimal solutions. In literature, few models combine location analysis, least cost planning, and emission assessment, taking into account multiple technologies which might achieve emission reduction goals. In this paper, an existing optimal location model for electric urban transport is adapted to match the needs of regional transport. The model, which aims to evaluate well-to-wheel carbon emissions as well as airborne emissions of NOx and PM10, is applied to a real case study of a regional bus transport service in North Eastern Italy. The optimization has identified electric buses with relatively small (60 kWh) batteries as the best compromise for reducing carbon equivalent emissions; however, under current economic conditions in Italy, the life cycle cost of such vehicles is still much higher than those of Euro VI diesel buses. In this context, our model helps in identifying ways to minimize infrastructure costs and to efficiently allocate expensive resources such as electric buses to the routes where the maximum environmental benefit can be achieved.
