Abstract: The invention provides a cargo bed structure comprising a sub-floor assembly comprising a plurality of cross members in spaced relation and a cargo bed defined by a longitudinally extending load-bearing deck overlying the sub-floor assembly and comprising a plurality of interlocking fiber reinforced polymer decking planks extending in a direction perpendicular to the cross members; an upwardly extending bulkhead assembly comprising at least one fiber reinforced polymer panel; a tailboard opposing the bulkhead and spaced apart therefrom; and two opposing upwardly-extending sidewalls, wherein each of the sidewalls and the tailboard comprise at least one fiber reinforced polymer panel pivotally mounted to the load-bearing deck.