Grahamh said:They are good value in Germany but in Switzerland you need two, one for the car and one for the caravan. I found Germany a bit unsettling due to the speed of traffic on the motorways. I am used to watching out for coaches and prepared for the buffet as they pass but in Germany you get cars coming by at 120mph+ and the turbulence is quite bad.
You just keep an eye on your outside mirror for vehicles approaching with their left indicator flashing - that is the one nearest the central crash barrier. It is generally understood to mean 'get out of my way - I'm coming past at all costs.' When you see such just drift towards the hard shoulder to maximise the distance between you and the high speed nutter and there will be very little if any buffet effect.