similar material from which the endcaps 22 are formed thus a compression fit could be provided in the above described mounting however adhesive bonding is the preferred method of mounting the endcap 22 is of a modular design allowing for an interlocking fit with other endcaps of the same design each endcap 22 has a lip 40 and 42 of reduced material thickness along its shorter edges thereby creating bearing surfaces 44 and 46 offset from the surface of the base web portion 26 as shown in fig2 the bearing surfaces 44 and 46 of the lips 40 and 42 on each end of the endcap 22 are disposed on opposites sides of the base web portion 26 thereby providing complementary recesses for adjacent endcaps 22 this allows the ends of two endcaps 22 to correspondingly overlap and mate with each other each endcap 22 is positioned such that the bearing surfaces 46 of the lip 42 on each endcap 22 faces the bearing surface 44 of the lip 40 of the other endcap 22 thereby positioning the base web portions 26 of each endcap 22 such that they are co planar and flush with each other therefore more than one endcap 22 may be installed along the edge 23 of running boards 10 having extra length this modular design facilitates easy replacement of damaged portions of endcaps 22 installed along the edge 23 of the running board 10 the modular design also enables greater economy.