Background Under the Kyoto Protocol, the EU has committed itself to reducing its greenhouse gas emissions to 8% below its 1990 level by 2008-2012. Today, over 97% of transport related energy comes from crude oil, with heavy vehicles generally running on diesel. However, the European Commission is seeking to substitute 20% of conventional fuels with alternative road fuels by the year 2020. Currently, dimethyl ether (DME) is the alternative fuel with the best ‘well-to-wheel’ energy efficiency. Furthermore, if produced from biomass, it is almost carbon dioxide (CO2) neutral. It is therefore considered one of the most promising fuel options for the future. Objectives The project’s objective was to demonstrate the feasibility of DME technology for heavy duty vehicles, by building and running four DME prototype lorries. One vehicle would serve testing and development purposes, while the remaining three prototypes would be customised to perform municipal tasks for the City of Växjö, Sweden. The initiative would also address the issue of DME storage and distribution, by building and operating a demonstration DME fuel station. Within Europe the main alternative diesel engine biofuel candidate is synthetic diesel. The motivation for the DME Vehicle project was that the more energy- and cost-efficient alternative of DME requires new infrastructure. DME Vehicle aimed to contribute to a better cost assessment of a paradigm change, with the further aim that the results would also serve as input to other European Commission initiatives. One important objective of DME Vehicle would be to match DME efforts in, for example, Asia (several DME initiatives have been made in both Japan and China). Results The intended main objective of DME Vehicle was to demonstrate the feasibility of DME technology developed within the AFFORHD project (EC FP5 AFFORDH - EC Fifth Framework programme project: Alternative fuel for heavy duty), by using four prototype heavy duty distribution vehicles. Attention was to be paid to challenging technical areas of DME vehicle applications, the driver’s interface and infrastructure. Special attention was also to be paid to vehicle operation under extreme temperatures, to verify system solutions. The main objective has not been achieved, as persistent technical problems of the fuel injection equipment (FIE) system, with several component failures, ultimately led to the cancellation of all prototype vehicles. However, the technical problems, together with the Failure Modes and Effects Analysis (FMEA) activities, also necessitated a thorough investigation into the complete system solution, which has proved extremely instructive. Consequently, weak design features of the AFFORHD fuel system were identified and can be avoided in the next generation fuel system. The second objective to address and demonstrate DME fuel infrastructure/distribution and contribute to a better cost assessment of a paradigm change could not be achieved since the field test vehicles were not put into service.