It is an element that allows two trailers to be joined together to be pulled. Allows trailers to be hooked up and moved. Dollies are built on a chassis section, with one or two axes with mechanical suspension, a fifth wheel and air brake systems.
Results in trailers being more efficient in the ton / kilometer ratio.
Allows the link between two trailers, increasing the transferred load.
Improves cost performance.
Allows connection with its fifth wheel to the kingpin of the trailer to be pulled, giving a greater support.