Extendable trailers are typically used in a STGO-type heavy haulage operation. That means that the load is either too heavy for standard operation or - more likely for extendible semi trailers - too long for standard use.
Using an extendable trailer gives the operator flexibility and eases transport to and from the delivery sites when unloaded.
There are a few specialist dealers in the UK who will always keep a selection of extendable trailers for sale. These trailers represent significant investment for the initial purchaser and typically hold value well, if looked after. It is unlikely that an operator without significant experience in moving long loads would be looking at purchasing such specialist kit.
Using an Extendable Trailer
Operating over weight trailers falls under the STGO regulations (Special Types General Order). If your trailer extends to over 6.1 metres wide or 30 metres long then the operator needs a special order - this needs to be kept in the vehicle.
You will need an attendant if the width exceeds 3.5 metres or if the trailer is longer than 18.75 metres.