It's easy to make a real mess of driving up and down mountains in Switzerland. First, give way to anything going up. Second, always give way to a PostBus - whether it's going up or down. Third, if you meet a train on the road, follow it (if it's going the same way as you) or go round it (if it's coming towards you on your side of the road). Speeding fines necessitate taking out a second mortgage so be good.