3. A DECELERATION INDICATING SWITCH ADAPTED TO BE MOUNTED ON A VEHICLE FOR UNITARY MOVEMENT THEREWITH AND COMPRISING, A HOUSING HAVING A SIDE WALL AND SPACED LEADING AND TRAILING END WALLS OF INSULATING MATERIAL, A PAIR OF SPACED BUS BARS DISPOSED WITHIN SAID HOUSING AND EXTENDING THROUGH SAID END WALLS FOR CONNECTION WITHIN A DECLERATION SIGNALING CIRCUIT, A PAIR OF SPACED METALLIC TRACKS DISPOSED BETWEEN SAID BARS AND CONNECTED TO THE LATTER, RESPECTIVELY WITH AT LEAST ONE OF SAID TRACKS BEING PROVIDED WITH A SLEEVE OF INSULATING MATERIAL CONSTITUTING A SEAT ADJACENT SAID TRAILING END WALL FOR INSULATING SAID LAST MENTIONED TRACK FROM THE OTHER TRACK AT SAID LATTER WALL, A METALLIC BALL ROTATABLE ON SAID TRACKS IN SPACED