in rotation will reflect half cycle contact with insulator 63 an open circuit will reflect point a on the conductor and for the next half cycle contact will be made on the square shaped metal rotation shaft 62 reflecting a grounding with repect to point a thus as the vehicle increases its speed rotation of the rotation shaft 62 will increase in like measure and point a relative to the grounding switch 6 will shift between grounding and open more frequently as a result the discharging frequency of capacitor in the rc circuit will increase in proportion the same effects will be achieved by replacing said square shaped rotation shaft by a cam shaft 72 presumably the grounding frequency of the grounding switch 6 should increase as vehicle speeds increases and that the charging discharging frequency in the rc circuit should be in synchronism with the grounding frequency in practice due to restrictions of the time constant of rc components charging and discharging frequency in the rc circuit will terminates its increase upon reaching a critical saturation condition defined by and as dependent on the particular values of the rc components in use in application this means that the flashing period will not approach zero regardless of the prevailing vehicle speed for instance if the flashing period of a vehicle speed is set at 10 seconds at speeds around 40 km per hour and.