Multifilamentary core yarns of brittle, high-modulus materials are partially encased in a \u201cwrapper\u201d of another material. The composition of the solution of the first material is selected so it dries to leave a residue of the first material on the substrate, the residue comprising a thin film in the centre and a ridge around the perimeter. Another step involves transmitting such signal generated in a previous step to a means disposed in a predetermined location on such motor vehicle for generating a reverse phase signal. The hydrogen-based ashing process following the initial hydrogen surface pretreatment substantially reduces surface chemistry poisoning, while retaining adequate adhesion properties following ashing. The primary metallic island has a greater height or thickness than the metallic circuit traces.