A structural member for a vehicle has a slot extending into one structural wall thereof, for receiving and holding a bolt, wherein said structural member including said slot has been formed by extrusion. The slot extends the length of the structural member for slidably receiving the head of one or more bolts wherein the land area of each bolt head extends beyond the slot opening to overlay the wall area carrying the slot. Each bolt carries at least two flat faces below its head wherein the juxtaposed edges of the slot carrying wall retains, i.e., refrains, the bolt from rotating. The slot includes an interior wall or sidewalls continuous with the slotted structural wall. The structural member may include an I-beam, a rectangular tube, a C-channel and the like. Corners are radiuses and right angles are avoided to reduce or remove stress risers.