Abstract: A step having a width substantially equal to the width of a person's feet is positioned on a pair of support arms extending angularly upwardly relative to the top surface of the step. The support arms terminate in upstanding portions which are engaged by a bracket assembly connecting them to the vehicle frame. The bracket assembly includes a first pair of plates on opposite sides of the vehicle frame and a third plate is positioned on the side of the upstanding portion opposite one of the pair of plates. Bolts interconnect the pair of plates and also the one plate to the third plate to rigidly connect the step to the frame of the vehicle. A brace extends from a point above the support arm connection to the upstanding portion and extends outwardly and downwardly to engagement with a side wall extending around the entire periphery of the step which includes a top plate having a plurality of elongated openings alternating with rows of circular openings over the substantial area of the plate.