Longer Semi-Trailer Trial

GB Longer Semi-trailer Trial (LST):  UPDATE 18 January 2024
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 new regulations to permit widespread LST use came in to force.

The new regulations include requirements for operators to identify their LSTs on their Operator Licence and to do simple (documented) route planning and risk assessment.

Any operator may now run LSTs under the new regulations.  Operators who had LSTs running on the trial have until 29 February 2024 to adjust their proceses to comply with the new regulations.  Risk Solutions are supporting the transition by providing help and advice to operators making the move.

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?

When the main trial ended in May 2023, there were 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
  • 78-86 million vehicle kilometres, and almost 630,000 journeys saved up to the end of 2021
  • 70,000 tonnes of CO2(e) and 97 tonnes of NOx have been saved
  • on a per kilometre basis LSTs have been involved in about 61% fewer personal injury collisions and casualties than the GB articulated heavy goods vehicle (HGV) average.

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 and so moved to develop the new LST Regulations.  The consultation documents along with the DfT Impact Assessment of the trial to date are available on the DFT website.

Risk Solutions support the Department in the role of independent evaluation consultants, 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 relating to the trial and new regulations should be addressed directly to the Department for Transport, freight@dft.gov.uk

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