Longer semi

Published 30 May 2023

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This publication is available at https://www.gov.uk/government/publications/longer-semi-trailer-lst-implementation-guide-for-operators/longer-semi-trailers-full-implementation-guide-for-operators

This guidance is aimed at current and potential operators of longer semi-trailers (LSTs). Following an extensive trial, a public consultation and regulatory changes, LSTs are being brought into general use. This guide is aimed at helping operators get the most out of LSTs, as well as ensuring that they are operated safely.

As a new vehicle type, LSTs are subject to specific regulations. These are explained in more detail in this document. The Road Vehicles (Authorisation of Special Types) (General) (Amendment) Order 2023 is the legal instrument which governs the use of LSTs and which should be read alongside this guidance.

In particular, route plans and risk assessments are legally required for each route on which an LST is planned to be used. The use of diversionary routes, where a normal route is or becomes unavailable, are also governed by the regulations.

In addition, the Secretary of State is legally required to be notified by operators of the prospective use of LSTs – which should be done through the vehicle operator licensing (VOL) system – with operators also required to ensure that drivers are given copies of the route plans and risk assessments for the routes they drive on. Each of these areas is covered in more detail in this guide.

In addition to these new legal requirements, the trial has shown some areas where operators choosing to operate LSTs should put in place new practices. These include driver training and scheduling, record keeping, broader staff training (including transport managers and other staff) and loading of LSTs.

It is expected of responsible LST operators that they provide appropriate training and enact processes and procedures to maintain safety. Implementation of these practices will also help to maintain the efficient and appropriate use of LSTs, which the trial has demonstrated provide significant economic benefits to operators.

Finally, those operators who have until now been taking part in the LST trial are subject to specific guidance, covering the process of ending the trial.

Longer semi-trailers, or LSTs, are a type of heavy goods vehicle (HGV) trailer up to 2.05 metres longer than the current standard semi-trailers on our roads – 15.65 metres instead of 13.6 metres. These are not the road-trains permitted in some other countries or the 25.25 metres designs in use in some EU countries.

The total weight of the LST, the goods and the tractor unit must still be within the UK domestic weight limit of 44 tonnes. They must pass the turning circle test applied to the existing 13.6 metre trailers, for which the LSTs require a steered rear axle.

Fully loaded LSTs can move the same volume of goods using fewer journeys than current trailers, for little change in fuel use per mile, while reducing overall emissions, congestion, and collision risk.

LSTs complement other approaches to freight carbon reduction, such as modal shift, increasing engine efficiency, and the use of electric vehicles, but LSTs can be implemented without the need for further significant technological and infrastructure development.

Image description: An image showing the difference in the number of standard UK pallets longer semi-trailers can carry when compared to standard semi-trailers. Per deck, longer semi-trailers can carry 4 more standard UK pallets than standard semi-trailers.

The Department for Transport (DfT) ran a national trial of LSTs starting in 2012, involving around 2,700 trailers and around 300 operators of all sizes and representing diverse types of cargo and operation.

Extensive data gathering throughout the trial monitored real world:

Analyses also included road class usage, emissions savings, and the impact of different designs.

The trial demonstrated that, with appropriate operational management, LSTs can be operated safely and deliver up to a 13 to 14% reduction in real world emissions, with an average saving of 8 to 9% across the whole trial. The trial also carried out route modelling and specialist analysis of the impact of LSTs on vulnerable road user groups.

Following demonstration of consistent trial safety and emissions performance, DfT has introduced regulations to permit LSTs to be used widely across Great Britain (GB).

The conclusion from the trial is that, while LSTs can be safely integrated into many freight operations, they do need some special management and monitoring by a responsible operator, beyond that needed for standard semi-trailers.

LSTs are therefore subject to some rules, set out in regulations. This guidance sets out more detail to assist in the interpretation of these regulations but does not have legal force.

The general objective of these rules is to ensure good safety performance continues, that additional practices designed to protect other road users are maintained, and that the efficiency advantages of LSTs are utilised.

The published road vehicles (authorisation of special types) regulatory impact assessment discusses the objectives and effects in more depth.

The LST order and this guidance apply to the use of LSTs in Great Britain. LSTs are defined as a special vehicle type under section 44 of the road traffic act (1988).

Abnormal indivisible load vehicles, low loaders and stepframe low loaders are excluded from the definition of LSTs in the LST order.

LSTs must be longer than standard semi-trailers. In order to achieve this, The definition in the LST order requires that the longitudinal distance from the axis of the king pin to the rear of the trailer must exceed 12.5 metres – in the case of an LST that is a car transporter – or 12 metres in any other case.

The maximum permitted length of an LST is up to 15.65 metres, which is 2.05 metres longer than the maximum length of a normal semi-trailer. Vehicle combinations including LSTs are articulated lorries with a maximum combination length of 18.55 metres.

Where a semi-trailer is capable of extension, it is only capable of operation as a longer semi-trailer when extended so that it exceeds the distances set out above.

The maximum combination length is applicable in all circumstances. Operators should note that use of aerodynamic devices, elongated cabs or other equipment does not affect the maximum combination length applicable for a longer semi-trailer.

The total combination length when operating a longer semi-trailer must not exceed 18.55 metres for any reason. A load carried by a LST must not have a rearward projection.

Other length related requirements are broadly the same as those in the trial. The maximum distance measured parallel to the longitudinal axis of any of the semi-trailers from the foremost point of the loading area to the rear of the semi-trailer must not exceed 15.65 metres.

The longitudinal distance from the axis of the king pin to the rear of any of the semi-trailers shall not exceed 14.05 metres.

The technical requirements of the trial included a requirement that no point in the semi-trailer forward of the transverse plane passing through the axis of the king pin shall be more than 2.04 metres from the axis of the king pin.

This limit, applying to swing radius, is not included in the LST order and does not apply outside of the trial.

Steering arrangements and electronic systems have to meet certain international technical provisions. All LSTs must have a minimum of three axles, one of which must be capable of steering.

Where the maximum authorised weight of a vehicle-combination which includes an LST exceeds 38 tonnes, the LST must be equipped with an on-board weighing device.

As set out above, the maximum weight limits for LSTs do not differ from those for standard semi-trailers.

Operators and society will only benefit from the introduction of LSTs if they can be operated safely and efficiently – by utilising the additional space.

The LST order are intended to permit widespread use of LSTs, while also emphasising that they need some additional management compared to other trailers.

Operators are expected to consider whether their use is appropriate, including:

if the expected fill levels use the additional space and so reduce journey count

if the types of routes involved are compatible with the safe operation of LSTs

if the operator fulfils the requirements for route planning and risk assessment

monitoring, training, and record keeping is done adequately and consistently

While not covered by regulation, clients purchasing haulage should be encouraged to be aware of the factors involved in operating LSTs efficiently and safely.

There are many other factors to consider before adopting LSTs, as noted by operators during the LST trial and published by DfT in Introducing and managing LSTs: an industry-led summary of good practice.

These factors include:

The operation of an LST without meeting the requirements of the LST order would be a breach of section 42 of the Road Traffic Act (1988). The Driver and Vehicle Standards Agency (DVSA) have published their policy about sanctions applicable to these breaches, and includes financial penalties for operators and drivers.

The DVSA can also refer operators to a traffic commissioner who may consider taking regulatory action against the operator's licence or HGV driving entitlement.

DfT's conclusion from the trial was that LSTs could be operated without a limit on numbers, but with some additional conditions set out in the LST order. In particular, the trial concluded that proper planning and risk assessment of the routes that are to be used by LSTs was a main contributor to the safe operation of the trailers.

The purpose is to ensure LSTs are only used on routes where their characteristics can be accommodated without increasing the risk of collisions or placing unreasonable demands on the driver.

Operators who wish to operate LSTs under the new regulations need to take a number of actions before doing so. Fulfilling these conditions is a legal requirement and they are set out in this section.

Operators who have taken part in the LST trial are subject to different requirements, until the conclusion of the trial. They are set out in the Transitioning from the LST trial section.

Before a longer semi-trailer is first used on a road by an operator, the operator must notify the Secretary of State for Transport.

The regulations require that this notification must be made by electronic communication, must specify the name and address of the operator, and (if the operator holds an operator's licence in respect of the LST), must specify the number of that licence.

If an operator's licence is held, notification must take place through the existing Vehicle operator Licencing (VOL) system.

Where an operator of an LST does not have an operator licence, the DVSA can be notified by email at [email protected].

Where the longer semi-trailer has been in the operator's lawful possession for less than one month, they are not required to make this notification. This should cover the majority of non-standard uses such as unladen LST movements in connection with:

The main reason for operators notifying their intention to use LSTs prior to their first use on a road is to ensure road safety is maintained, and to help inform future reviews.

The requirement to notify the intention to use an LST will cease after 5 years from the date on which this order comes into force – see article 62(4) STGO, as inserted by article 4 of the LST order) so from 1 June 2028.

LSTs are required to comply with all other regulations which apply to standard semi-trailer use. This includes plating and testing requirements.

In particular, LSTs must meet the relevant requirements set out in the following legislation:

Within both the construction and use regulations and the approval regulations, turning circle requirements for semi-trailers can be demonstrated either by:

The latter does not therefore take account of any influence of how the steering axles may influence the path that the trailer follows. The extra reliance on operation of steering axles for longer semi-trailers to comply with turning circle requirements means that this basic calculation method cannot be relied on.

LSTs that are authorised for use in GB cannot be used in Northern Ireland unless they have been authorised in advance by the Department for Infrastructure in Northern Ireland.

Operators who wish to operate LSTs in Northern Ireland can contact the Department for Infrastructure at: [email protected] for further advice and guidance.

DfT is not prescribing a universal format for route plans and risk assessments. The regulations also do not prescribe a specific format, but state that risk assessments should make a suitable and sufficient assessment of specified factors.

The language of suitability and sufficiency is consistent with health and safety legislation. Our guide provides general principles based on insights from operators on the trial.

Operators are advised that they need to be able to demonstrate a route planning, risk assessment, and feedback process that is proportionate to the scale of the operation and number of drivers and routes involved, as well as the variety – road types, locations – and complexity of the routes being used.

The operator is legally required to keep a copy of the route plans and the risk assessments for a route for 2 years beginning with the date the LST was last used on that route. These should be retained such that on request from DVSA or a traffic commissioner they can be reviewed.

Operators may also wish, as a matter of good practice, to retain evidence of the following:

A copy of the route plan and risk assessment for an established route are legally required to be carried in the motor vehicle towing the LST when it is used on that route.

The requirements in the order for route planning and risk assessment for established routes sets them apart from the regulations of combinations of standard articulated lorries (including those with trailers with a height in excess of 4 metres) and rigid lorry-trailer combinations of a similar length.

However, subject to these requirements being satisfied, LSTs are as suitable for use on British roads as these other goods vehicle combinations are.

The purpose of route plans and risk assessments is to ensure that LSTs are only used on appropriate routes (risk assessed and planned by the operator), can be driven safely on those routes, and for risks to be reduced through both prior assessment and feedback.

Such routes are referred to by the regulations as established routes. An established route is defined as a route which is specified on a legally compliant route plan, and for which a legally compliant risk assessment has been completed.

Motorways and other modern strategic roads are designed for large volumes of traffic and large vehicles. Major and tight junctions, including those associated with the entrances and exits of motorways and other grade separated dual carriageways, are liable to need specific consideration.

Lesser roads can be used but there needs to be careful risk assessment, including related to road geometry and other road users – including pedestrians and cyclists.

To comply with the regulations, a route plan must be in writing, and specify the road or roads on which the LST is to be used in order to travel to and from its destination.

Each new route to or from a destination needs its own plan. Core elements for a route plan should give the driver:

It may be that multiple route options are assessed and approved for a single destination, with final route choice being made depending on traffic conditions.

To comply with the regulations, a risk assessment must be in writing. It must make a suitable and sufficient assessment of the risks of personal injury and injury to any animal, damage to any vehicle and damage to any other property of using the LST on the route specified on the route plan and conclude in the light of those risks that the route is one on which it would be reasonably safe to use an LST.

A risk assessment is suitable and sufficient if it considers all relevant risk factors, including:

The operator needs to be able to safely use both established routes and diversionary routes. There will be occasions on which an established route becomes unavailable, for example in the case of an accident closing part of the route. In this instance an operator will need either to use a diversionary route, or to utilise standard trailers to move the load.

A diversionary route is a route that includes roads or parts of roads which are not on an established route. The route must be one which enables the LST to reach or return to an established route as soon as reasonably practicable and must be reasonably considered by the operator to be safe for that purpose.

Diversionary routes may be used where:

In most cases, diversionary routes are expected to be used in scenario B above.

Where scenario A applies, the diversionary route may be used for a period of 7 days which begins on the day when the prohibition on the use of LSTs came into force, unless the prohibition is revoked or expires before the end of that period.

However, there may be cases where a problem on a route is apparent before the LST begins its journey. In such a case, an operator should use an alternative established route if it is reasonably practicable to do so.

Alternatively, if it is reasonably practicable to specify the diversionary route on a route plan, and to complete a risk assessment for it, then this should be done. Only if neither of these options is reasonably practicable should a diversionary route be used.

LST operators should be able to demonstrate that they have a process to check all journeys can be undertaken via risk assessed routes and that they require drivers to follow only risk assessed routes.

Compliance checking needs to be fit-for-purpose for the scale and complexity of the operation but must inform relevant managers about levels of route compliance.

As an element of this process, where drivers are found not to be complying with the planned routing, there should also be a process for, and evidence of, corrective action.

An LST operator should be able to show the DVSA or a traffic commissioner (on request) their process for route planning and compliance, and the actual routing, risk assessment and compliance records.

Copies of route plans and risk assessments must be retained for 2 years.

An LST operator will be expected to demonstrate that the process has the ability to lead to corrective action if required. This means that there should be a process for monitoring compliance internally, reporting it to a suitably responsible manager, and taking any required actions in response – all proportionate to the size of the operation.

Simple scenario: A very small operator operating a single LST design, on a single route at a fixed time of day, with 2 drivers involved.

Complex scenario: A national operator with 100 LSTs, of 2 designs, as part of a fleet of 1,000 trailers, with 800 drivers, each operating diverse routes each day.

Simple scenario: Plan a risk assessment in office with a single sheet of paper for the driver, with a map or turn by turn instructions and a reminder about major hazards.

Complex scenario: Route planning integrated into work management systems, with a library of pre-assessed route segment plans and risk assessments, with a process to produce route instructions for drivers on paper or loaded into satnavs, with hazard notes, where drivers are only assigned to routes hours before departure.

Simple scenario: Not available – single LST design.

Complex scenario: Risk assessment process allows for different outcomes, or even different routes, for 14.6 metre self-steer vs. 15.65 metre single command steer LSTs.

Simple scenario: Discussion with drivers of route suitability for LSTs and any hazards encountered – then added to risk assessment.

Complex scenario: Formal process for drivers to feed back on route suitability for LSTs and any hazards encountered – then added to risk assessment.

Simple scenario: Planned diversions discovered by drivers seeing roadside announcements – leading to alternative route-planning and risk assessment.

Complex scenario: Planned diversions may be noted by drivers, but operator also monitors National Highways 7-day and on-the-day closure plan data feed (and any information from local authorities). Formal process for triggering route re-planning and risk assessment.

Simple scenario: Driver finds safe stopping location and calls in to assess best course of action, including option of returning to base.

Complex scenario: Driver finds safe stopping location and calls fleet management to assess best course of action, resulting in either a live alternative route risk assessment or return to base.

Simple scenario: Discussion of route being used with drivers. Satnav track checks if available.

Complex scenario: Either sample checking of route tracks from satnav data or integrated functions for planned vs. actual route data in telematics system.

Other than route planning and risk assessment, the selection and training of drivers to use LSTs was suggested, by operators on the trial, as the most important management action taken to ensure safe operation of the trailers.

While drivers and operators fed back that the trailers operated normally in general driving – stability, braking – this was always with a caveat that some additional care and skill was needed when making manoeuvres involving turning or tighter spaces, due to the additional length and the steering axle.

Operators also noted the importance of familiarity of drivers with specific LST designs, and the effect on their skills of the frequency with which they used the trailers.

Specific driver training is not a requirement under the regulations. However, operators are strongly encouraged to ensure that drivers are appropriately trained in the use of LSTs, as part of their general duty to ensure the safety of operations and staff.

LST operators should ensure a driver has had appropriate LST-specific training, relevant to the particular type of LST driven, before a driver uses the trailers. Written advice notes may complement, but will not adequately replace, training.

Training should be a minimum of half a day, but this can be made up of a mixture of classroom or computer-based instruction and on-the road instruction and supervision.

Any classroom or computer-based instruction should be delivered by an organisation accredited to provide driver certification of professional competence (DCPC) training, although the instruction involved need not be accredited for DCPC.

Practical training may also be provided by the operator or other organisations.

Where a driver transfers employer or is provided by an agency, the new operator should verify that relevant LST training has taken place or else ensure it is provided.

Operators on the trial noted the following as important considerations in designing fit-for-purpose LST training:

Training should be proportionate and reflect the nature of the individual routes likely to be used, as well as the familiarity of drivers with their routes, frequency with which they use LSTs and whether they move between standard trailers and LSTs in a single shift.

Both infrequent use of LSTs and in-shift switching from standard trailer to LST were identified as driving some increase in small incidents for one operator on the trial.

The driver's training should be specific to the LST designs they will use:

LST lengths can be different lengths in excess of 13.6 metre up to 15.65 metre, each with different characteristics

self-steer (passive), command (forced – connected to 5th wheel), or active steer (computer controlled) designs have significantly different characteristics

for larger operators, it is beneficial to have an LST training and good practice guide document to ensure consistency in training

refresher training should be considered, especially if drivers use LSTs infrequently

some companies may decide to set a driver experience threshold for using LSTs

The regulations relating to LSTs have been designed to allow the widest possible use of LSTs, while reinforcing that they are different from standard trailers. Drivers need to be aware that LSTs are different and how this affects them and their employer.

Drivers are legally required to be provided with copies of the route plan and risk assessment for any journey they are undertaking using an LST. These are legally required to be carried in the cab. This can be in an electronic format.

For any trip involving an LST, drivers should be trained to expect:

to be given a planned route and risk assessment

to be able to provide route feedback, including additional potential hazards to be added to the assessment

to follow the planned route and that this may be monitored

Drivers should be aware of the importance of clear incident reporting.

Finally, drivers should be aware of the role of the DVSA in monitoring LST regulatory compliance by operators in relation to all the areas covered by this guidance.

The effectiveness of LST driver training can vary, depending on the work patterns imposed on drivers by the nature of the operators’ business.

Two work patterns were identified as challenging for drivers, and an analysis by one major operator suggested these patterns led to increases in accidents:

very infrequent use of LSTs in a shift pattern dominated by use of standard trailers led to skills fade, especially if LST use fell to less that once in 2 weeks

switching between LSTs and other trailers within a single shift, perhaps several times, increased the demand on drivers to adjust their driving approach

Fit-for-purpose management of LSTs may therefore extend beyond individual route planning and driver training, to also include risks arising from wider driver management and considerations of these issues in work planning.

As a guide, LST operators should be able to show the traffic commissioner or other authority (on request) both their process for driver training and evidence of its use.

An operator should reasonably be able to show:

evidence of training plans and any materials used

evidence of each driver's LST training record and how it links to work assignment

evidence that LSTs are only being operated by drivers with the relevant training

evidence that, if multiple LST designs are in use, the training and records consider the design differences in both the risk assessment and training

Trial operators also highlighted the importance of other staff in ensuring efficient and safe operation of LSTs. They include:

The likely need to consider relevant LST awareness and training for staff other than drivers is noted in the findings of the trial.

As a guide, operators should consider some or all of the following examples:

transport managers’, other fleet and driver managers’ awareness of the:

loaders’ awareness of any special conditions, in particular individual axle loading

warehouse managers’, planners’ and logistics software providers’ awareness of the demands of mix load sizes (26 vs. 30 pallets) and any restrictions on which bays can be used by LSTs

maintenance teams’ and providers’ awareness of manufacturers’ requirements and procedures for each design of steered axle present in the fleet

compliance managers’ awareness of the regulations relating to LSTs and especially the record keeping requirements

senior managers’ and commercial teams’ awareness of the special nature of and regulations for LSTs in business planning and contract negotiation

site and facilities managers’ awareness of the spatial needs of LSTs, especially in turning and reversing (which differs depending on the steering type), and the impact of LSTs on other vehicles, site traffic flow and parking.

The issue is explored in more depth in DfT's Introducing and managing LSTs: an industry-led summary of good practice.

The guidance in this section applies only to operators participating in the GB LST Trial. These are defined as those operators that already have LSTs operating under a vehicle special order (VSO) that is live on 31 May 2023, when the Road Vehicles (Authorisation of Special Types) (Amendment) Order 2023 comes into force.

Operators not holding a live LST VSO on this date are not expected to join the trial, which will consequently be wound down. They should notify the Secretary of State of their intent to use LSTs, as set out in Conditions of use for new LST operators section, as appropriate.

Operators on the LST trial may transition their existing LSTs to the new regime at any time in a transition period that starts on 31 May 2023 and lasts until 30 November 2023.

Operators will be notified by the VCA of the revised end date of the VSOs applicable to their vehicles. After this date, unless and until they notify the Secretary of State of their intent to use LSTs under the new regulation, as per section above, they will not be able to legally operate LSTs.

During the transition period:

existing trailers remain on the trial until their VSO has expired or is revoked (at the conclusion of the trial or once they have notified the Secretary of State of their intent to use LSTs under the new regulation). They will continue to be required to comply with the requirements of the trial, submitting any data requested

operators holding a live VSO on the policy implementation date may remove some LSTs from their fleet and retain others on the trial, but may not add new LSTs to their trial fleet. New trailers must be notified to the Secretary of State, even if the operator still has other LSTs operating under the trial conditions

In relation to all other conditions (route planning, risk assessment etc.), operators must ensure their systems used under the trial already meet, or are adjusted to meet, the special conditions for the general use of LSTs from the day the trailers move to the new regime. Our recommendations for driver training also apply.

Trial data reporting requirements apply up to the date the trailers move to the new regime. Any final data submissions should be made soon after the move.

In relation to record keeping, the requirements to keep copies of route plans and risk assessments as per the new conditions for the 2-year period will apply from the date the operator moves to the new regime (i.e. there is no retrospective requirement to hold records required under the new system, for operations undertaken during the trial).

All LST operations under trial conditions will cease at the end of the transition period, at which time:

any remaining live VSOs will be revoked, and any associated trailers will not be able to operate on the road until their operators have notified the Secretary of State of their intention to use the particular LSTs on a road

all trial data reporting requirements will cease

Any retention of LST trial data and contact records will be conducted in line with published guidance for operators joining the trial.

An anonymised version of the numerical data – with all company information redacted and data aggregated so as not to be disclosive – may be created as a data source for later reference by DfT use in analysis of LST performance.

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