A traffic sign for use in a paved road has a housing with an open upper end. A holder is vertically movably received in the housing. A light emitting unit is installed in the holder to move therewith. A transparent plate is mounted on the holder to move therewith. The transparent plate permits a light from the light emitting unit to transmit therethrough. A space is defined between a bottom of the housing and a lower end of the holder to permit the vertical movement of the holder in the housing. An elastic support ring has an inner wall fixed to an outer surface of the holder and an outer wall fixed to an inner surface of the housing. Projections are formed on the elastic support ring. Each projection projects upward beyond the transparent plate. Recesses are provided by the elastic support ring. Each recess is defined between the projections, so that the light from the light emitting unit is viewed through the transparent plate and each of the recesses.