Are road trains legal in the UK?

In short: no—Australian‑style multi‑trailer “road trains” are not legal on UK public roads. The UK allows only single‑trailer heavy goods combinations within strict size and weight limits, with a limited exception for nationally approved Longer Semi‑Trailers (LSTs) up to 18.55 metres in Great Britain. Below is a detailed look at what is—and isn’t—permitted, and how current rules compare to the “road train” concept.

What “road trains” usually mean—and why the UK says no

In common usage, “road trains” refers to very long, heavy multi‑trailer combinations widely seen on remote Australian routes (for example, B‑doubles and B‑triples that can exceed 50 metres and 100 tonnes). UK law does not permit such multi‑trailer goods vehicles on public highways. The UK’s road network, urban density, and safety framework underpin limits on the number of trailers, overall length, and weight.

What is legal today on UK roads

The UK permits several established heavy vehicle configurations, subject to national Construction & Use Regulations and specific safety requirements. The items below outline combinations operators can legally run on public roads and the conditions attached to them.

• Standard articulated lorries: An articulated tractor unit towing a single semi‑trailer, up to 16.5 m overall length (typically up to 44 tonnes on six axles for domestic haulage).
• Drawbar combinations: A rigid truck towing a single drawbar trailer, up to 18.75 m overall length (weight limits apply as above).
• Longer Semi‑Trailers (LSTs): Since 31 May 2023, LSTs up to 18.55 m are permitted across Great Britain (England, Scotland, Wales). They remain capped at standard domestic maximum weights (generally 44 tonnes) and require route risk assessments, driver training, and operational controls. Northern Ireland has a separate regulatory regime and has not adopted the GB LST roll‑out.
• Abnormal indivisible loads (STGO): Oversize/overweight moves can exceed standard limits under Special Types General Order with police/highway notifications and tight conditions. These moves typically still involve one trailer (albeit with specialist equipment) and are not general‑purpose multi‑trailer “road trains.”

Together, these configurations reflect the UK’s preference for single‑trailer operations with carefully managed extensions (like LSTs) where safety and infrastructure impacts can be controlled.

What is not legal (and where trials stand)

The following covers vehicle types and concepts often associated with “road trains” that are not currently allowed on UK public roads, along with the status of any policy discussions.

• Australian‑style multi‑trailer road trains: Multiple full‑size freight trailers (e.g., B‑doubles/B‑triples) are not permitted on public roads in the UK.
• 25.25 m “European Modular System” (EMS) combinations: Unlike some EU states, Great Britain has not authorised general EMS operations. Government work has focused instead on the controlled roll‑out of 18.55 m LSTs.
• Heavier‑than‑44‑tonne general freight: Routine operation above 44 tonnes is not allowed; only abnormal indivisible loads move heavier under STGO. (Separate, limited allowances for certain low‑ or zero‑emission HGVs do not create multi‑trailer permissions.)
• Driverless/platooned “road trains”: Truck platooning without a responsible driver in each cab is not legal. The UK’s Automated Vehicles Act (2024) sets a path for future approvals, but no general authorisation exists for platooned HGV “trains” on public roads.

In practice, these prohibitions keep UK operations within a single‑trailer framework while policymakers evaluate incremental changes like LSTs rather than multi‑trailer road trains.

Key reasons behind the UK stance

Regulators cite road geometry, junction design, urban exposure, and mixed‑traffic safety risks as the main barriers to multi‑trailer adoption. While longer vehicles can offer efficiency gains, the UK approach has been to trial and then regulate modest extensions (LSTs) with route mapping and training, rather than permit significantly longer or heavier “trains.”

Tourist “land trains” and special cases

So‑called trackless “land trains” that carry passengers on promenades or seafronts usually operate off‑highway or under tightly controlled local permissions. Carrying fare‑paying passengers in towed trailers on public roads is heavily restricted, and these vehicles must meet specific licensing, construction, and route conditions where they are permitted. They are distinct from freight “road trains.”

Compliance essentials for operators using LSTs

Operators adopting the 18.55 m LST option in Great Britain must meet added compliance steps to ensure safety on specified routes.

• Undertake route risk assessments that consider junctions, roundabouts, and yard access; keep documentation up to date.
• Train drivers on LST handling, turning circles, and defensive driving for vulnerable road users.
• Monitor performance and incidents, adjusting routes and procedures where necessary, and comply with DVSA enforcement.

These measures are designed to capture efficiency benefits while maintaining safety and protecting infrastructure—an approach that differs markedly from permitting multi‑trailer road trains.

Bottom line

UK law does not allow Australian‑style multi‑trailer road trains on public roads. The permitted envelope remains single‑trailer operations—standard artics, drawbar rigs, and, since 2023, 18.55 m Longer Semi‑Trailers in Great Britain under strict conditions. Multi‑trailer “road trains,” EMS‑length combinations, and driverless platoons are not legal at this time.

Summary

Road trains, in the Australian multi‑trailer sense, are not legal in the UK. Great Britain permits single‑trailer HGVs within set length/weight limits and has rolled out 18.55 m Longer Semi‑Trailers nationwide with additional safeguards. Heavier or much longer multi‑trailer combinations, and platooned HGV “trains” without a driver in each cab, remain prohibited on UK public roads.

Which countries allow road trains?

Contents

• 2.1 Australia.
• 2.2 United States.
• 2.3 Europe.
• 2.4 Mexico.
• 2.5 Zimbabwe.
• 2.6 India.

Why are road trains only in Australia?

Road trains are unique to Australia due to the nation’s vast, sparsely populated landscape, limited railway infrastructure, and specific road network, which are all tailored to accommodate these long, heavy vehicles for cost-effective and efficient long-distance transport of goods and resources in remote regions. Unlike other countries with congested, narrow roads and higher population densities, Australia’s flat, wide, and straight outback roads are designed for the enormous length and weight of road trains, allowing them to operate safely. 
Factors unique to Australia’s geography and infrastructure:

• Vast, remote, and sparsely populated areas: Australia’s immense size and low population density in many regions make it uneconomical to build extensive railway networks. Road trains are the most efficient way to transport goods over these long distances where other transport is limited. 
• Suitable road network: The long, straight, and wide roads in the Australian Outback, such as the Eyre Highway, are specifically designed to accommodate the turning radius and weight of road trains. 
• Limited railway coverage: While Australia has some railway lines, particularly for mining, they do not provide the comprehensive network needed to serve the country’s vast interior, making road trains a vital alternative. 
• Regulatory environment: Australia has specific regulations and allows for road trains to reach greater lengths and weights than in many other countries, such as Europe or North America. 

Economic and logistical advantages:

• Cost-effectiveness: Operating a single road train is more cost-effective than running multiple individual trucks for the same cargo capacity. 
• Efficiency: They are designed to haul large volumes of cargo, including livestock, fuel, and building materials, over vast distances, connecting remote communities and industries. 
• Flexibility: Road trains can access remote locations and travel on a variety of road surfaces, from paved highways to dirt tracks. 

Limitations in other countries: 

• Infrastructure limitations: Most countries, particularly densely populated ones, have road networks that are not designed for vehicles as long and heavy as road trains, with narrow roads, sharp turns, and infrastructure not built for such loads.
• Safety concerns: The long braking distance and difficulties with turning and overtaking make road trains a hazard on busy, congested roads, where they would cause traffic chaos and liability.
• Population density and congestion: High population density and congestion in other countries would make road trains impractical and dangerous, leading to them being banned.

Is train hopping illegal in the UK?

In the United Kingdom, train surfing is prohibited under railway byelaw No. 10, which prohibits travelling in or on any train except in areas of the train intended for use by that person.

Are road trains allowed in the UK?

The maximum individual truck length is 12 metres, articulated truck and trailer length is 16.5 metres and road trains are allowed up to 18.75 metres. The maximum width for all is 2.55 metres.