A running board for a passenger car or light truck is assembled from an upper molded thermoplastic section or component having a Class A automotive finish and a lower component or section having reinforcing ribs and mounting brackets. The upper section includes three layers: a paint film having a Class A automotive finish, a thin layer of thermoplastic polyolefin (TPO) and a thick layer of polypropylene. The lower section is homogeneous and may be a plastic such as TPO, polypropylene or high-density polyethylene (HDPE), for example, which may contain chopped, randomly oriented glass reinforcing fibers. The two sections are secured to one another about their peripheries by autogenous bonding.