CAR RENTAL IN AUSTRIA
If you plan to rent a car during your trip, you can rent it either in Zurich Airport or Friedrichafen.
You have to be aware of the speed limit in Switzerland and drive carrefully. If you pass the speed limit and the police catches you, you have to pay on the spot. They take credit cards...
The other thing to watch out is the distance between your car and the one in front of you. Radars in Switzerland also check this : don't be too close ! Otherwise, they flash you.
There is radars in every tunnels, and sometimes, they are hidden in big Swiss cheese ads along the higway !
The drive from Zurich to Lustenau is a couple of hours.