Wind turbine blades, transformers, plant and machinery, bridge beams, modular buildings — the loads that don’t fit inside standard construction and use limits keep much of British industry moving. They also move under one of the more technical corners of road transport law, and it’s a corner where guesswork gets expensive: prohibited movements, prosecutions, civil liability for bridge and street furniture damage, and Traffic Commissioner interest in the operator behind it all.
When is a load ‘abnormal’?
A load is an abnormal indivisible load (AIL) when it cannot, without undue expense or risk of damage, be divided — and its vehicle exceeds the normal limits in the Road Vehicles (Construction and Use) Regulations 1986: broadly, more than 44 tonnes gross weight, more than 2.9 metres wide, or over-length. Movements beyond C&U limits run under the Special Types General Order (STGO), which sets three categories by weight — Category 1 up to 50 tonnes, Category 2 up to 80 tonnes, Category 3 up to 150 tonnes — each with its own axle limits, speed restrictions and plating requirements. Beyond 150 tonnes, or beyond STGO dimensional limits, individual Special Order authorisation from National Highways is required.
Notification is where most mistakes happen
Depending on weight and dimensions, movements must be notified in advance to the police forces along the route, to highway and bridge authorities (who need two clear days for most STGO weight movements, longer for the heaviest), and — for the heaviest categories — with indemnities lodged against bridge damage. In practice notifications are made through ESDAL, National Highways’ online system, which also helps plan the route against structures. The recurring failures are mundane: notifying the wrong authorities because the route changed, missing a force boundary, moving early, or treating notice periods as targets rather than legal minimums. Every one of them can stop a movement — or worse, be discovered after an incident.
Escorts, equipment and the driver
Wider and longer loads bring marking and lighting requirements, attendant requirements, and — under police and National Highways guidance — self-escort arrangements with trained escort drivers for many movements that police forces no longer escort themselves. Speed limits differ by STGO category and road type. Route planning has to respect structure assessments and physical reality: a legally notified route still has to actually fit. And bridge strikes remain the industry’s most visible failure — see our guide to why bridge strikes keep happening.
Training for planners and drivers
Abnormal loads knowledge traditionally lives in a few experienced heads per operator — a risk in itself as those people retire. Our online Abnormal Loads Transportation course puts the framework on record for transport planners, transport managers and drivers: C&U limits and STGO categories, notification duties and ESDAL, marking, attendants and escorts, speed limits and route planning. It’s completed online with a certificate for your compliance file.
For operators building broader compliance, it sits alongside our operator licence guide and Operator Licence Awareness Training — because everything above ultimately answers to your O-licence undertakings.
Leave a Reply