A parking brake actuator system for an outdoor power equipment unit, such as a riding lawn mower, comprises a reversible electric motor that drives a gear reduction assembly. The gear reduction assembly rotates an output shaft at a speed slower than the speed of rotation of the motor. The output shaft has opposite ends that are linked by a pair of actuating rods to a pair of parking brakes. As the motor is rotated in reverse rotary directions, the connecting portions of the rods that are coupled to the parking brakes are moved in opposite, straight line directions to move the parking brakes between brake disengaged and brake engaged positions.