Road Vehicles (Authorisation of Special Types) (General) Order 2003 (STGO)

STGO, the Road Vehicles (Authorisation of Special Types) (General) Order 2003, lets abnormal loads and mobile cranes use public roads. This guide covers the weight categories, the notice rules and how they apply to mobile cranes and machine moves.

Overview

What STGO covers

Abnormal loads and mobile cranes travel on public roads under the Road Vehicles (Authorisation of Special Types) (General) Order 2003, known as STGO. It lets vehicles over the standard weight and size limits run on the road, as long as they meet the Order’s conditions.

In short

A load qualifies only if it is indivisible (see Key definitions).
Vehicles fall into Categories 1 to 3 by weight, up to 150 t, and mobile cranes into Categories A to C.
Above 44 t, every road and bridge authority on the route gets notice and an indemnity.
A load over 5 m wide needs VR1 consent before it moves, and over 6.1 m wide, 30 m long or 150 t it needs a Special Order.

Full title	Road Vehicles (Authorisation of Special Types) (General) Order 2003
Reference	Statutory instrument (SI) 2003/1998
Current version	The Order as amended by SI 2023/524. The revised text on legislation.gov.uk shows no outstanding changes.
Publisher	The National Archives, on legislation.gov.uk
Status	In force
Legal status	An Order made under section 44 of the Road Traffic Act 1988, exempting vehicles that meet its conditions from the standard road vehicle rules.
Extent	Great Britain
Northern Ireland	Motor Vehicles (Authorisation of Special Types) Order (Northern Ireland) 1997

Duty holders

Who has duties under the Order

Most duties, including giving notice and providing attendants, fall on “the user of the vehicle”, in practice the operator moving it (article 15 and article 17). The driver must not drive onto a bridge that another abnormal load is already on, or stop on one unless forced to (article 18). The DVSA special types enforcement guide asks operators to plan every abnormal load move separately and secure the load properly.

A blue wooden boat on its carriage strapped to a low loader trailer behind a lorry with a red loader crane, parked on gravel — A boat on its carriage secured to a low loader trailer.

Requirements

What the Order requires

Abnormal load vehicles are grouped by gross weight in Schedule 1.

Category 1	Combinations up to 46 t, or 50 t on six or more axles. Up to 60 mph on motorways.
Category 2	Up to 80 t. Up to 40 mph on motorways.
Category 3	Up to 150 t. Up to 40 mph on motorways.

The vehicle may be up to 6.1 m wide and 30 m long, with a category sign at the front. The bigger and heavier the load, the more notice it needs and the more attendants travel with it.

Over 3 m wide, or a side projection over 305 mm	Notify the police (article 15)
Over 3.5 m wide	Attendants as well
Over 5 m wide	Secretary of State consent before the journey, applied for from National Highways on form VR1
Over 18.75 m rigid, or 25.9 m as a combination	Police notice and an attendant (article 12)
Over 44 t	Notice and an indemnity to every road and bridge authority on the route (article 17)
Over 80 t	Police notice too, and 5 days’ notice to road and bridge authorities

Notice is otherwise 2 days, and Saturdays, Sundays and public holidays do not count (article 3). Moves can be notified through National Highways’ online system, ESDAL. Moves outside the Order need a Special Order, applied for on form BE16 at least 8 weeks ahead, or 10 weeks as National Highways advises, and to Transport Scotland for Scottish moves.

Lifting

How the Order applies to lifting and machine moving

Mobile cranes have their own schedule, Schedule 2, and fall into Category A, B or C by axle and gross weights. Category C cranes go up to 150 t and are limited to 40 mph on motorways. A crane may travel only to and from lifting work, or for testing, demonstration, delivery or repair. It may not carry anything but its own equipment, or tow a trailer. Notice works the same way as for loads, so a crane over 80 t needs 2 days’ notice to the police and 5 to road and bridge authorities. The DVSA guide notes that since May 2018 mobile cranes have needed an annual test and a plate showing their permitted weights.

On a machine move, a press or machine tool that cannot sensibly be stripped down can travel as an abnormal indivisible load. If it can be split into loads within the standard limits, each part travels under the standard rules.

A lorry carrying a boat on a trailer through a narrow street lined with buildings, with people in high visibility clothing walking alongside — A load moving through a narrow street with people walking alongside.

Definitions

Key definitions

Abnormal indivisible load: a load that cannot be divided without undue expense or risk of damage, and cannot be carried on an ordinary lorry or trailer because of its size or weight (Schedule 1, paragraph 2).
Mobile crane: a vehicle over 12 t built for lifting work, with the crane permanently mounted, driven by someone on board and registered as a mobile crane (Schedule 2, paragraph 2).
Engineering plant: movable plant built for work that an ordinary vehicle cannot safely do, covered by Schedule 3.
Special Order: an individual authorisation for a move outside the Order’s limits.

Enforcement

Enforcement and penalties

There is no offence of breaking STGO itself. The DVSA guide explains that a vehicle breaking the Order’s conditions loses its protection, and the Construction and Use and Authorised Weight rules then apply in full. Once outside the Order, an overweight or unsafe vehicle can be prosecuted under the Road Traffic Act 1988, for example section 40A on dangerous condition or section 41B on weight. Speeding by an abnormal load vehicle can be brought to the traffic commissioner’s attention.

In Northern Ireland the 1997 Order applies. Moves are notified to the Police Service of Northern Ireland and the Department for Infrastructure (nidirect: transporting abnormal loads), and the Driver and Vehicle Agency enforces. The Department is consulting until 9 November 2026 on bringing the Northern Ireland rules into line with Great Britain’s.

Guidance

Guidance and sources

National Highways publishes an aide memoire on notification requirements that sets the thresholds out on one page, and runs the ESDAL helpdesk.

Sources and further reading

Questions

Common questions

When does a machine move count as an abnormal load?

When the load cannot be divided and the vehicle carrying it goes over the standard limits, such as 44 t gross or 2.9 m wide, according to National Highways.

How much notice does an abnormal load need?

2 days to the police where the width, length or a weight over 80 t triggers it, and to road and bridge authorities for loads over 44 t. Authorities need 5 days for loads over 80 t, and a Special Order at least 8 weeks.