The transportation sector is responsible for 37% of the total final energy consumption in Jordan, with passenger cars taking a share of 57% in this sector. Improvement of the energy efficiency of the transportation sector can help in alleviating socio-economic pressures resulting from the inflating fuel bill and in lowering the relatively high CO2 emission intensity. Current legislations mandate that all passenger cars operating in Jordan are to be powered with spark ignition engines using gasoline fuel. This paper examines potential benefits that can be achieved through the introduction of diesel cars to the passenger cars market in Jordan. Three scenarios are suggested for implementation and investigated with a forecasting model on the basis of local and global trends over the period 2007-2027. It is demonstrated that introducing diesel passenger cars can slow down the growth of energy consumption in the transportation sector resulting in significant savings in the national fuel bill. It is also shown that this is an effective and feasible option for cutting down CO2 emissions. (C) 2007 Elsevier Ltd. All rights reserved.