A successful trial of longer semi-trailers (LSTs) could make them a permanent fixture on Britain’s roads.

Longer than conventional heavy goods vehicles (HGVs) but not heavier, LSTs can carry three more rows of supermarket goods cages on each journey compared with existing trailers.

The trial of LSTs, which has been on-going for the past seven years, has shown that they have saved commercial fleet operators from travelling millions of miles, cutting emissions and boosting productivity.

In the past year alone, the 2,600 vehicles involved in the trial have saved lorry drivers 33.5 million miles and 48,000 tonnes of CO2 – equivalent to taking over 20,000 cars off the road.

The results also show the trailers were involved in fewer personal injury collisions compared with standard size HGVs, says the Department for Transport (DfT). 

Off the back of these positive results, the Government has proposed to end the trials early and, through a consultation, seek views on whether LSTs should be allowed to permanently operate on roads across the UK. 

Transport Secretary Grant Shapps said: “These trials clearly show the benefits for business and the environment of using longer trailers.

“By determining the next steps to get them on our roads permanently, we can benefit industry and our economy, boost safety and cut emissions.”

The Department for Transport is also launching a further consultation on proposals to start a trial of slightly heavier HGVs on UK roads, which could see the maximum weight of some HGVs increased by 4 tonnes to 48 tonnes.

The change suggested in the consultation would allow lorries to transport heavier containers direct to or from freight trains, helping to shift more cargo from road-only journeys onto rail, and therefore cutting emissions and congestion on our roads, further demonstrating government commitment to make haulage more environmentally friendly, says DfT.

The proposed trial would operate on around 10 routes cleared as safe for use by 48-tonne vehicles and would look at whether it encouraged a shift of goods from road to rail.

Phil Lloyd, head of engineering policy at Logistics UK, welcomed the Government announcement. 

"An industry trial has shown the benefits to the environment and the economy on the use of LSTs, and with the ability to carry more goods per journey than traditional trailers, they present a cost-efficient, environmentally prudent alternative to current transportation options," he said. 

"It is good news that the Government has taken heed of the findings.  

"If our industry can move the same amount of goods with fewer journeys, the environment, the economy and other road users will benefit – Logistics UK is supporting the switch to LSTs wholeheartedly and is grateful for the opportunity to consult on these vital vehicles.”