A roof bow for a trailer body for use with a commercial motor vehicle is provided, including a top wall, a floor, and a pair of side walls cooperating to define a cargo space, and a plurality of supports each extending substantially across the trailer body between the side walls. The top wall includes an interior surface and an exterior surface, and the supports are connected to the exterior surface of the top wall such that at least a substantial portion of the interior surface of the top wall is generally smooth. The roof bow has a uniform cross-sectional shape along its length and having a crown joining with side walls and a pair of attachment pads, the bow forming an interior cavity with the pads having inwardly extending leg extensions.