Ascend Transport insurance
February 4, 2021

What to know about transporting abnormal loads


Abnormal Loads


Vehicles are usually limited by the Road Vehicles (Construction and Use) Regulations 1986 (“C&U”) in terms of the load they can carry. Long, heavy or wide loads will usually be transport under the Abnormal Indivisible Loads provisions of the Motor Vehicle (Authorisation of Special Types) General Order 2003 (“STGO”).


Abnormal Indivisible loads (AILs) are loads which cannot, without undue expense or risk or damage, be divided into two or more loads for the purpose of carriage on the road and which cannot be carried on vehicles operating within the limitations of the C&U regulations.


Number of Abnormal Loads

Normally, only one abnormal load is permitted to be carried at any one time. However, two or more abnormal loads may be carried on one vehicle provided the loads are from the same place, being delivered to the same place and are of the same character.



A ‘Special Types’ vehicle must not normally exceed 30m, but where a load is carried on a combination of vehicle and trailers, or on a long articulated vehicle, the dimension of 30m is measured excluding the drawing vehicle.



Special Types vehicles are normally permitted to be up to 2.9m but, if necessary to ensure the safe carriage of large loads, they may be up to a 6.1m wide. Anything over 2.9m will require two days notice to be given to each police force which the vehicle passes through. Anything over 3.5m wide will also require an attendant in addition to the two days notice. Anything over 5m wide will require a Special Order from the Highways Agency (in addition to the two days notice and an attendant).



The maximum permissible overall weight of a special types vehicle is 150 tonnes. There are also individual axle and wheel limits which must not be exceeded.


Vehicle Categories and Identification Signs – There are three separate weight categories for abnormal loads and to be displayed on front of vehicle:


STGO Cat 1 for up to 50 tonnes

STGO Cat 2 for up to 80 tonnes

STGO Cat 3 for up to 150 tonnes

Vehicle Excise Duty for Special types Vehicles

Special Types vehicles have a separate VED taxation class


Speed Limits

Special Type vehicles are limited to speed based upon their Category and the type of road. These are as follows:


Vehicle Activity


Dual Carriageway

Other Road

Category 1




Category 2 or 3




Vehicles carrying wide loads (i.e. over 4.3m) are restricted to yet slower speeds.



An attendant must be carried on Special Types vehicles if:


(i) The vehicle or load is more than 3.5m wide (ii) Overall length of the vehicle is more than 18.75m (iii) Length of vehicle and trailer exceeds 25.9m (iv) Load projects more than 2m beyond the front of the vehicle (v) Load projects more than 3.05m beyond the rear of the vehicle


Police Notification

The police force through which a Special Types combination is to be moved, must be given two clear days’ notice if:


(i) Vehicle or load is more than 3m wide; (ii) Vehicle or load is more than 18.75m (excluding tractor unit in articulation combination); (iii) Combination of vehicle and trailer, including projections, is more than 2.9m long; (iv) Load projections are more than 3.05m to front or rear; (v) Gross weight of vehicle and load is more than 80 tonnes.


Notification of highway and bridge authorities

If a Special Types vehicle and load weighs more than 80 tonnes (i.e. category 2 or 3), or the weight imposed on the road by the wheels of such a vehicle exceeds the maximum limit in the C&U regulation, then the following notices must be given to the Highway and Bridge Authorities for the areas through which the vehicle is intended to pass:


(i) 5 clear days, or (ii) 2 clear days (if only C&U axle weight limit is exceeded).


Any vehicle over 44 tonnes must be moved off a bridge as soon as possible (if it has to stop on it). If it has broken down, then the advice of the bridge authority must be sought before the vehicle is jacked up.


The Operator is also required to indemnify the authorities against damage to any road or bridge which it passes over.


Marker Boards


These must be carried in accordance with the requirements and confirm to the dimensions and colours required. They should also be indirectly illuminated at night.


Side projections

Where an AIL:

– Extends 305mm, or more, on one or both sides of the vehicle, or exceeds 2.9m overall, then the police must be given two clear days’ notice, and end marker boards must be displayed front and rear within 50mm of the edge of the load.

– Exceeds 3.5m then police notification, end marker boards and an attendant are required.


Forward Projections

Where a load projects more than:

– 2m beyond the front of the vehicle: approved side and end marker boards and an attendant.

– 3.0m beyond the front of the vehicle: police must be given two days’ notice of its movement, side and end approved marker boards and an attendant.

– More than 4.5m beyond the front: the requirements mentioned above must be observed and additional side marker boards must be carried within 2.5m of the first set of side markers.

Rearward Projections

When a load projects the rear of the vehicle by more than:


– 1m: it must be rendered clearly visible

– 2m: an end marker board must be displayed

– 3.05m: police must be notified, attendant must be carried and approved side and end marker boards displayed.

– 5m: additional side marker boards must be carried within 3.5m of the first set of side markers.