Many of the effects of longer semi-trailers (LSTs), such as the overall reduction in journeys compared to normal length semi-trailers, are assessed across the whole network. LSTs are mainly operating on trunking journeys, but need ready access to depots, supplier sites and larger retail sites, in many cases near, but not on, motorways or trunk roads. There is ongoing work being carried out about where the LSTs operate, including their use on urban roads.
The vehicles have the same weight limits as normal length semi- trailers. They are no longer than some lorries drawing full trailers allowed in general circulation.