Longer Semi-Trailer Trial

GB Longer Semi-trailer Trial (LST):  UPDATE 10 May 2023
DfT Announces new regulations for widespead use of LSTs and end date for trial

On 10th May 2023, the UK Department for Transport announced that their 11 year GB Trial of Longer Semi-Trailers (LSTs) would come to an end within the year.  From June 2023 DfT will introduce new regulations to permit widespread LST use, subject to a few sensible requirements, including route risk assessment and staff training.  Operators will have a 6 month transition window (June-November) to move their existing LSTs over to the new regulatory system (continuing to run under the terms of the trial until they do so).

This is the end of a long journey for Risk Solutions and our partners WSP.  We have had the privilege of acting as independent evaluators of the trial throughout the whole 11 years, engaging with more that 300 participating companies running almost 3000 of these new trailers

What is a Longer Semi-trailer?

A Longer Semi-Trailer (LST) is an extended articulated lorry trailer, measuring up to 2.05 metres longer than a standard vehicle, but are still limited to the standard UK maximum Gross Vehicle Weight of 44 tonnes.  By carrying up to 15% more cargo on each trip, savings can be made in both journey numbers and harmful emissions.  

The extended trial was closely monitored by an evaluation team led by Risk Solutions, in collaboration with the participating haulage operators.  Millions of records of trip data were gathered along with details of all major incidents, and deep dive assessments   looking at routes, emissions, risk controls and every aspect of LST operations.  From this data the evaluation confirmed that the potential savings could be realised in real world operations (not just in desktop calculations) and that the trailers could be operated with no increase in the average risk to other roads users or the public, compared to standard articulated lorries.

About the trial

The trial was designed to evaluate whether, when put into a real-world operation, these trailers:

  • Are operated efficiently, giving real savings in journeys and emissions?
  • Can be operated as safely (or better) than the standard trailers they replace?

As of May 2023, there are almost 3000 LST on GB roads.
Up to the end of 2020 the trial results indicated that:

  • on average, the use of LSTs reduced journey numbers by 1 in 12, with the highest performing applications saving 1 journey in 8
  • 66-73 million vehicle kilometres, and almost 600,000 journeys saved up to the end of 2020
  • 60,000 tonnes of CO2(e) and 96 tonnes of NOx have been saved
  • on a per kilometre basis LSTs have been involved in about 47% fewer personal injury collisions and casualties than the GB articulated heavy goods vehicle (HGV) average.  The yet to be published figures for 2021 are even better.

Over the life of the trial. DfT has published a series of documents produced by Risk Solutions of which the latest are:

After a consultation in 2020, DfT stated publically that the trial has reached a point where continuing to the scheduled end in 2027 was unlikely to provide further useful results and that remaining issues, relating to the safety, can only be answered outside of trial settings.   So, in parallel with the evaluation reports, the department has launched a public consultation asking if they should end the existing longer semi-trailer (LST) trial,a nd move ahead with one of several potential future operational options with differing levels of regulation.

The consultation documents along with the DfT Impact Assessment of the trial to date are available on the DFT website.

Risk Solutions has continued to support the Department in the role of independent evaluation consultants, both in continuing to monitor the trial (with a lower level of detailed data collection) and acting as a reviewer of the emerging policy, regulations and guidance, from the perspective of ensuring what is claimed and planned can be truly supported by the evidence from the trial.

Further information:

The annual reports from every year of the trial can be found on the Department for Transport’s website at www.gov.uk/government/collections/longer-semi-trailer-trial#progress-reports.

Trial participants can send any enquiries related to the data collection or end of trial arrangements to Risk Solutions on 01925 413984 or at LSTTrial@risksol.co.uk

All enquiries not related to the data collection or analysis should be addressed directly to:
Michael Sedgwick at the Department for Transport, Telephone: 07500 573572
or email:  michael.sedgwick@dft.gov.uk

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