It said using longer semi-trailers to transport goods between warehouses and depots has saved up to 10.6 million vehicle kilometres.
DfT added the scheme, which involves approximately 1800 trucks, is also expected to save over 3000 tonnes of CO₂ emissions.
“Lorries are the engine of our economy and this pilot scheme is helping hauliers deliver the day-to-day goods we need more efficiently,” said transport minister, John Hayes.
“This is good news for consumers, a boost for motorists as it is helping cut congestion with fewer vehicles on the road, and it is also helping the environment.”
The government said the economic benefits of the project are estimated at £33 million over the next 10 years, with British hauliers saving up to one in nine journeys with trucks that are up to 15 per cent longer than standard 13.60 m vehicles.
Despite the bigger size, the outfits still meet existing manoeuvrability requirements and maximum weight limit of 44 tonnes for six-axle vehicles.
The DfT said the new trucks have also proven safer. It said nationally, they have been involved in around 70 per cent fewer collisions and casualties per kilometre compared to the average for standard articulated vehicles.
“Following these positive results, we are consulting trade associations and participants on whether to increase the number of vehicles in the trial,” the DfT said in a statement to the press, adding it was are also seeking views on extending the trial, which was originally launched as part of the government’s 2011 logistics growth review.