The use of aluminium alloy instead of steel for the structural components of a 32 ton articulated lorry has been examined. The probable manufacturing difficulties have been assessed and shown to be minimal. The savings in weight possible by using aluminium have been calculated from a structural analysis of the cab, tractor chassis and trailer and from this and an assessment of the manufacturing processes the extra cost of manufacturing in aluminium has been determined. A typical case study shows that this extra cost can be easily recovered by utilising the increased load capacity of the vehicle during the first few years of its life.