as long as you are under 4mts no problem,used to see the car transporters at St Louis letting the tyres down on the cars so they could get below 4mts ...
hopefully this should work
The road pricing system for heavy vehicles came into effect on January 1st, 2001. All Swiss and foreign vehicles weighing more than 3.5 tonnes must pay the tax to use the road networks in Switzerland and neighbouring Liechtenstein.
The road tax is a key element of Switzerland's transport policy aimed at reducing heavy vehicle crossings of the Alps to 650,000 by 2009. In 2003, there were over one million such transits, which was a drop of eight per cent compared with 2000.
In 2004, the charge levied on a 40 tonne truck crossing the Swiss Alps was SFr215. That went up to SFr307 a year later, and if the government does not renege on its plan, will rise to SFr325 in 2008. But road hauliers argue that the tax has not had the desired effect, nor will it have when the rate is increased in two years' time.