This study presents a methodology to develop scenarios of evolution from 2010 to 2050, for energy consumption and emissions (CO2, HC, CO, NOx, PM) of the road transportation sector (light-duty and heavy-duty vehicles). The methodology is applied to Portugal and results are analyzed in a life-cycle perspective. A BAU trend and 5 additional scenarios are explored: Policy-based (Portuguese political targets considered); Liquid fuels-based (dependency on liquid fuels and no deployment of alternative refueling infrastructure); Diversified (introduction of a wide diversity of alternative vehicle technology/energy sources); Electricity vision (deployment of a wide spread electricity recharging infrastructure); Hydrogen pathway (a broad hydrogen refueling infrastructure is deployed). Total life-cycle energy consumption could decrease between 2 and 66% in 2050 relatively to 2010, while CO2 emissions will decrease between 7 and 73% in 2050 relatively to 2010. In 2050 the BAU scenario remains 30% above the 1990 level for energy consumption and CO2 emissions; the other considered scenarios lead to 4 to 29% reductions for energy consumption and 10 to 33% for CO2 emissions in 2050 compared to the BAU. Therefore, alternative vehicle technologies are required in the long-term, but changes in taxation and alternative transportation modes policies are crucial for achieving short-term impacts. (c) 2012 Elsevier Ltd. All rights reserved.