Heavy haulage tractor units are designed and licensed to operate at much higher weights than the UK legal 44 tonnes. Used in combination with specialist trailers, these trucks can operate at train weights of up to 150 tonnes. Controlled by the STGO...
Under the 'Special Types General Order', (STGO) regulations there are three categories that relate to the gross train weights of the vehicles and load. You will usually see the 'STGO' plates affixed to the front of the trucks, followed by a category number.
There is no need to carry movement order notices in all categories of these types of vehicle.
This is the smallest of the abnormal load category with gross weights up to 50 tonnes (assuming 6 axles in total, otherwise just 46 tonnes is the maximum permissible in this class.
This category has a maximum gross train weight of 80 tonnes and must use at least 6 axles. The weight must be spread relatively evenly across the axles, with no single axle weight higher than 12.5 tonnes. Operating speeds are lower here, with a maximum motorway speed of 40mph.
The giants of the abnormal load world can operate at up to 150 tonnes GTW - they must have more than five axles and are limited to a maximum axle weight of 16.5 tonnes. Whilst categories 1 and 2 require just two days notice to the highways and bridge authorities, the category 3 transports need to advise the authorities 5 working days before the transport is due to take place.
You must have a special order for vehicles more than 150 Tons or 16.5 Tons per axle, or if they are 6.1 metres wide or 30 metres long in rigid length when loaded . As with the Cat 3 STGO regulations, you’ll need to give: 5 working days’ notice to highway and bridge authorities and 2 working days’ notice to police.
You must carry the special order authorisation for the vehicle movement in the vehicle.
The answer is yes if the vehicle/load width exceeds 3.5 metres or the trailer (not including the tractor unit) exceeds 18.75 metres (or the total length exceeds 25.9 metres) and finally if projections exceed 2 metres (front) 3.05 metres (rear).
Where an attendant is needed they can travel in the vehicle according to the STGO or Special Order movement. Alternatively they can travel in an escort vehicle, providing that they are
in radio contact with the vehicle concerned
and can keep the vehicle in sight.