The DfT has relaunched its longer semi-trailer trial, following a consultation this summer, and in a significant concession, has said the market will be left to decide the mix of longer trailer variants within the scheme.

Under the re-booted scheme, which is live now, the DfT has opened up longer semi-trailer applications on a first come first served basis, irrespective of whether operators are involved in the current trial.

Launched in 2012, the longer semi-trailer trial has since put less than 550 of the trailers on the road to date from the trial target of 1,800 allocations. Of this just over 100 are understood to be at the shorter 14.6m length.

With December’s deadline to use existing allocations fast approaching, the DfT conceded early this year that the target would not be met.

Under the trial revisions, existing allocations will be honoured. But in a departure to the previous framework, operators already in the scheme will be able to swap their existing allocations for an alternate length ahead of the December deadline.

A spokesman for the DfT also confirmed to that the original 900/900 longer semi-trailer split (between the 14.6m and 15.65m trailer lengths), had now been relaxed. “The 1,800 cap remains and it will be driven by the market – so not restricted to 900 of each,” he confirmed.

Under the revised scheme operators can apply for as many additional permits to run longer-semi trailers - at which ever length they want - until the 1,800 limit is reached. Operators are however still capped at running no more longer-semi trailers than is equivalent to 20% of their existing semi-trailer fleet, or 180 longer semi-trailers.

Permit extension

In its consultation document the DfT suggested new longer semi-trailer allocations would have been valid for just two to three months as part of the revised scheme, something manufactures warned was not a viable timescale.

In response, the DfT has said operators now have a maximum of six months to supply it with proof of order to show their commitment to purchase a longer semi-trailer trial, in a bid to stop operators "sitting" on permits and not actually putting trial units on the road.

Transport minister Stephen Hammond said: “Longer semi-trailers enable freight companies to transport more goods, more efficiently, and should give significant economic and environmental benefits.

"We want to maximise their use during the trail to ensure we properly assess the benefits.”