Reducing energy consumption and CO2 emissions in the transport sector is a priority for Great Britain and other European countries as part of their agreements made in the Kyoto protocol and the Voluntary Agreement. To achieve these goals, it has been proposed to increase the market share of diesel vehicles which are more efficient than petrol ones. Based on partial approaches, previous research concluded that increasing the share of diesel vehicles will decrease CO2 emissions (see ; ). Unlike these approaches, I use an integral approach based on discrete choice models to analyse diesel vehicle penetration in a broader context of transport in Great Britain. I provide for the first time, empirical evidence which is in line with argument that only improvements in vehicle efficiency will not be enough to achieve their goals of mitigation of energy consumption and CO2 emissions. The model shows the technical limitations that the penetration of diesel vehicles faces and that a combination of improvements in public transportation and taxes on fuel prices is the most effective policy combination to reduce the total amount of energy consumption and CO2 emissions among the analysed dieselisation polices.