Abnormal loads

Advice should be sorted before carrying loads outside of the normal Construction and Use regulations requirements. See the link to Logistics UKs yearbook chapter below for further information. 


The dimensions and weights of vehicles used on British roads are regulated by the Road Vehicles (Construction & Use) Regulations 1986 (C&U) and the Road Vehicles (Authorised Weight) Regulations 1998 (AW). 


Special types vehicles are those which don’t meet the C&U and AW Regs but can be used outside these rules under the authority of the Road Vehicles (Authorisation of Special Types) (General) Order 2003 (STGO). 


Vehicles that are more likely to be used under an STGO are:  

  • Abnormal indivisible load (AIL): loads which can’t be divided into two or more loads to be transported by road.

  • Mobile cranes: specially built, or adapted, for lifting operations.

  • Engineering plant: a moveable piece of plant or equipment which is a motor vehicle or trailer specially built for engineering operations.

  • Road recovery vehicles: vehicles that are specially built for recovering broken-down vehicles. 


Vehicles which don’t comply with an STGO order can be used under Special Orders issued by either National Highways or the Vehicle Certification Agency (VCA) regarding special vehicles and divisible loads such as crane ballast outside the scope of C&U and STGO. These orders called Individual Vehicle Special Orders (IVSO), were previously known as Section 44 Permits.  


Loads which comply with C&U and AW Regs can’t be carried on an abnormal Indivisible load vehicle, even as a backload. Generally, an ‘abnormal load’ is one carried on a vehicle that has any of the following: 

  • A weight of more than 44t maximum authorised mass (MAM).

  • An axle load of more than 10t for a single non-driving axle and 11.5t for a single driving axle. 

  • A width of more than 2.9 metres. 

  • A rigid length of more than 18.65 metres. 


Abnormal indivisible loads vehicles are normally divided into three categories:  


Category 1 not exceeding 46t / 50t MAM:

  • Up to 46t MAM with a minimum of five axles. 

  • Up to 50t with a minimum of six axles. 


Category 2 not exceeding 80t MAM: 

  • Minimum of six axles. 

  • Maximum axle weight of 12.5t.


Category 3 not exceeding 150t MAM:

  • Minimum of six axles. 

  • Maximum axle weight of 16.5t. 


Operators must ensure compliance with notice periods, all regulations regarding carriage by road including the planning of your route using the help of the Electronic Service Delivery for Abnormal Loads (ESDAL) system, and making sure that the vehicle is signed accordingly. Refer to the Logistics UK Yearbook of Road Transport Law for further details.  

Download the abnormal loads chapter of the Yearbook of Road Transport Law

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