Maximum Trailer Dimensions

Towing vehicle up to 3500kg GVW

Length (excluding the coupling and drawbar): 7.0m

Width Maximum: 2.55m (was 2.3m up to 2010)

Towing vehicle over 3500kg GVW

Length (excluding the coupling and drawbar): 12m (min 4 wheels

Width Maximum: 2.55m

Length of towing vehicle and trailer combined: 18m

Maximum overhang of load from rear of trailer: 3.05m

Marking of rear overhang

  • Between 1m and 2m, ensure the end is clearly visible by attaching a piece of cloth or similar.
  • Between 2m and 3.05m, a marker board as defined in the Regulations must be fitted and illuminated at night.
  • If the overhang is more than 3.05m, an attendant must be carried and the police must be notified 2 days before commencing the journey.

"Long Vehicle" Marker Plate:

  • Not required for light trailers.
  • These are a legal requirement only for trailers over 3500kg or where the towing vehicle is over 7500kg gross weight. When they are required, different plates are required depending on the length of the vehicle. Details can be found in the Road Vehicle Lighting Regulations, Schedule 18.
  • Loads must not project more than 305mm either side of the trailer, up to a maximum width of 2.9m.
  • Loads over 2.9m in width are classed as abnormal loads and the police must be notified two days before a journey commences.

Recommended maximum height:

  • 3.0m high or 1.7 times the wheel track. (horizontal distance between centre lines of tyre treads).
  • There is no legal requirement, but this is an accepted guideline.
  • If however the height does exceed 3.0m then a notice giving the height details must be displayed in the cab of the towing vehicle.

(Only buses are subject to a maximum height regulation).

Safe & Legal Towing Guide Disclaimer