That extra wheel is mounted in a center-forward position and let Herbie spin on its own axis. A chain and linkage system kept the two front wheels moving to give the illusion that they were still on the ground doing the work. Controls were hidden in the floor in front of the backseat so the stunt driver could hide and make it look like Herbie was in charge.
According to Silodrome, the car was partially disassembled, but Mid America Motorworks fabricated a new secondary control system so the car is now driveable from the front or backseat and spins on its axis like it did on screen. The paint and interior are also restored to the way it looked in Herbie Goes Bananas.
It is also signed by Joaquin Garay III who played Paco, the character that created the car’s flower and taxi decorations. His signature is on the glove compartment and was kept during the restoration process. Place your bid on January 23 when Herbie goes up for auction through Barrett-Jackson in Scottsdale with no reserve.