• Maximum vehicle and trailer lengths and widths are laid down in the Road Vehicles (Construction and Use) Regulations 1986.

7.1 MAXIMUM LENGTH

• Measure overall length between the extreme forward and rearward projecting points.
• Containers and demountable bodies are included if they exceed the normal vehicle length.
• An extended tailboard is included where it is used as essential support for the load; otherwise it is not included.
• Major C & U maximum lengths in the source:
• Rigid vehicle: 12 m.
• Articulated vehicle: 16.5 m.
• Articulated vehicle using a low-loader semi-trailer: 18 m.
• Vehicle and drawbar trailer combination: 18.75 m.
• Drawbar trailer: 12 m where it has at least four wheels and is drawn by a motor vehicle over 3,500 kg gross weight; otherwise 7 m.
• Semi-trailer: maximum distance from king pin to rear = 12 m.
• For a normal square-fronted semi-trailer, the effective maximum distance from king pin to front is 1.6 m, giving an effective overall trailer length of 13.6 m.
• If there is more than one king-pin position, the 12 m measurement is taken from the rearmost king pin.
• Extra-long semi-trailers in the government trial could operate at 14.6 m or 15.65 m under the stated Vehicle Special Order scheme; the source states a maximum of 180 such vehicles for an individual operator.
• An articulated vehicle is defined in the source as a motor vehicle with a trailer superimposed on it so that, when uniformly loaded, at least 20% of the load weight is borne by the drawing vehicle.

7.2 MAXIMUM WIDTH

• Projecting freight containers and demountable bodies are included in the width calculation.
• Driving mirrors and direction indicators are excluded from overall width.
• Locomotives: 2.75 m.
• Refrigerated vehicles: 2.60 m.
• Other motor vehicles: 2.55 m.
• Trailers drawn by a motor vehicle: 2.60 m for refrigerated equipment and 2.55 m for others.
• The source states that most EU countries use the same general width limits.

7.3 MAXIMUM HEIGHT

• The source states there is no statutory maximum height for goods vehicles in the UK.
• Unmarked UK bridges are stated as likely to have a clearance of 16 ft 6 in.
• Most other EU countries apply a 4 m height limit.
• High double-deck trailers of around 5 m may therefore operate in the UK but generally not in most other EU countries.

7.4 HIGH VEHICLES – IN CAB NOTICES

• Vehicles with a travelling height exceeding 3 m must either display the overall travelling height in feet and inches prominently in the cab or carry accessible documents giving a route that avoids bridge/overhead hazards.
• Vehicles carrying high-level equipment such as a lorry-mounted crane must also have a warning device to alert the driver if the equipment becomes raised during a journey.