Abstract: An improved speed warning indicator for a speedometer comprises a transparent plate such as a transparent decal, having means such as an attached transparent plastic sheet bearing adhesive for attaching it to the transparent face cover of a speedometer casing containing a speedometer dial. The plate bears indicia, such as color and/or a plurality of spaced lines, etc. demarking the plate and the speedometer dial viewed through the plate, thereby indicating a speed warning on the dial while still permitting unobstructed viewing of all of the dial. Preferably, the plate is configured and dimensioned to overlie only a portion of the cover and dial so as to more clearly provide the speed warning. The plate can be affixed, in accordance with the present method, to the face cover of a fully assembled speedometer so as to provide very easily, simply and effectively, the improved speedometer of the invention.