Multicriterion Sustainability Assessment in Transportation: Private Cars, Carsharing, and Transit Buses

The increase in the number of hybrid electric vehicles and carshare users in the United States in the past decade urges transportation officials to incorporate vehicle characteristics into traditional transportation planning and sustainability assessments. This study updates the state of the art in three main ways: (a) employs a life-cycle approach instead of focusing only on the operation of modes, (b) disaggregates vehicles by type instead of assuming a uniform light-duty vehicle fleet, and (c) assesses conventional and hybrid technologies explicitly for travel mode combinations instead of assuming only fossil fuel–powered vehicles and private cars. The sustainability framework used in this study sets the direction for a multicriterion assessment of urban transportation. Six highway vehicles and modes are analyzed: an internal combustion engine vehicle (ICEV), a hybrid electric vehicle (HEV), a carsharing program with ICEVs, a carsharing program with HEVs, a diesel bus, and a hybrid diesel–electric bus. The three travel combinations are developed into three case studies: (a) passenger vehicle only, (b) passenger vehicle and public bus, and (c) carsharing and public bus. The results show that the inclusion of carsharing in the travel mix is the best option. The most sustainable mode, relative to the other five, is found to be carsharing with HEVs. The superior performance of carsharing over transit buses reveals opportunities for new policies in sustainable transportation.