the invention includes vehicle body panels , and vehicles containing such panels . the panels contain reinforcement that enables them when assembled to contribute to the structural strength of the vehicle . the basic volume of each panel is formed from plastics by reaction - injection moulding so that the panels are light in weight and would be inadequate , in the absence of the reinforcement , to withstand the structural loads . in a typical vehicle construction panels are arranged to form arches spanning from one side of the vehicle to the other , a succession of such arches being assembled together down the length of the vehicle . 1 . field of the invention