Braking Systems

Construction and Use Regulations 1986 cover braking systems under regulations 15, 16, 18(1), 19 and 87. The regulations are split as follows:

  • Regulation 15 and 16 Fitting Requirements 
  • Regulation 18(1) Maintenance and Efficiency 
  • Regulation 19 Application Of Brakes On Trailers 
  • Regulation 87 Exceeding Maximum GVW (Overloading) - Unbraked trailers 

There are additional requirements for motor vehicle/trailers that operate under STGO (Road Vehicles (Authorisation of Special Types) (General) Order 2003). 

Braking Systems 

  • Fitting Requirements 
  • Maintenance and Efficiency 
  • Application Of Brakes On Trailers 
  • Unbraked trailers 

Further information concerning the regulations as well as links to information on ABS and EBS braking can be found below.. 

Fitting Requirements 

Regulations 15 and 16 Road Vehicles (Construction and Use) Regulations 1986 concern braking systems which comply with Regulation 15 or which comply with Schedule 3 of the Construction and Use Regulations (Regulation 16) and are required to be fitted to all motor vehicles and trailers except: 

  • A steam-propelled locomotive first used before 2nd January 1933 with an engine which is capable of being reversed (a parking brake is still required), 
  • A trailer which is designed for use and used for street cleansing and does not carry any load other than its necessary gear and equipment, 
  • An agricultural trailer manufactured before 1st July 1947 with a laden weight not exceeding 4070 kg and drawn as the only trailer by a motor tractor or an agricultural motor vehicle at not more than 10 mph 
  • A trailer drawn by a motorcycle in accordance with regulation 84 
  • An agricultural trailed appliance 
  • An agricultural trailed appliance conveyor 
  • A broken-down vehicle 
  • A gritting trailer with a maximum gross weight not exceeding 2000 kg, or 
  • A trailer which has a maximum total design axle weight that does not exceed 750 kg, However, no person shall use cause or permit to be used on a road such an unbraked trailer, except an agricultural trailer if it falls within the bounds of Regulation 87 Road Vehicles (Construction and Use) Regulations 1986 whereupon: it is overloaded (its laden weight exceeds its maximum gross weight), or the weight of the trailer + load exceeds half the kerbside weight of the drawing vehicle 

In other words, brakes are required on a small trailer, unless the trailer falls within another exemption listed above or is an agricultural trailer, if it is overladen, or if the kerbside weight of the drawing vehicle is less than twice the total actual weight of the trailer; e.g. a 500 kg gross unbraked trailer must be towed by a motor vehicle with a kerbside weight of a least 1000 kg.  

The type of braking system required to be fitted to a vehicle depends on its type and age. EC braking requirements - regulation 15 - apply, in the main, to vehicles first used on or after 1st April 1983. Construction and Use requirements - regulation 16 - apply all other vehicles except those listed as exempt above. 

Maintenance and Efficiency 

Regulation 18(1) Road Vehicles (Construction and Use) Regulations 1986 concerns every part of every braking system and the means of operation fitted to a vehicle shall be maintained in good and efficient working order and be properly adjusted, except for defects on an anti-lock braking system during the journey on which the defect occurred or whilst being driven to a place of repair of the defect. 

Brakes must be maintained if they are fitted, even if they are not required. A brake drum or brake disc are part of the wheel and not the braking system - regulation 3(6). 

Minimum requirements for the total braking efficiency of a braking system are listed at regulation 18(3) and apply to all motor vehicles and all trailers which are required to have brakes fitted under regulations 15 and 16 except :

  • Agricultural motor vehicles are driven at not more than 20 mph 
  • A works trucks, 
  • Pedestrian controlled vehicles, and 
  • Industrial tractors 

braking system

Application of Brakes on Trailers 

Regulation 19 Road Vehicles (Construction and Use) Regulations 1986 states that where a trailer required to be fitted with brakes is drawn by a motor vehicle and the driver shall be in a position to operate the brakes to the motor vehicle and the trailer unless:

  • The trailer is fitted with overrun brakes, or 
  • The trailer is a broken down vehicle being drawn in such a manner that it cannot be steered by its own steering. If the vehicle is not broken down or otherwise exempt then it cannot, for instance, be towed front suspended for the delivery without some form of automatic braking system fitted 

In a locomotive, a competent person other than the driver may be used to apply the trailer brake. 

Unbraked trailers 

Regulation 87 Road Vehicles (Construction and Use) Regulations 1986 concerns unbraked trailers where it is overloaded i.e. its laden weight exceeds its maximum gross weight, or where the weight of the trailer plus its load exceeds half the kerbside weight of the drawing vehicle. 

Therefore, brakes are required on a small trailer, unless the trailer falls within another exemption or is an agricultural trailer, if it is overladen, or if the kerbside weight of the drawing vehicle is less than twice the total actual weight of the trailer; e.g. a 500 kg gross unbraked trailer must be towed by a motor vehicle with a kerbside weight of a least 1000 kg. 

The type of braking system required to be fitted to a vehicle depends on its type and age. EC braking requirements (regulation 15) would therefore apply in the main, to vehicles first used on or after 1st April 1983. Construction and Use requirements (regulation 16) apply to all other vehicles except those listed within the regulations as being exempt. 

Regulation 87 states that no person shall use, or cause or permit to be used, on a road an unbraked wheeled trailer if:

  • Its laden weight exceeds its maximum gross weight; or 
  • It is drawn by a vehicle of which the kerbside weight is less than twice the sum of the unladen weight of the trailer and the weight of any load which the trailer is carrying 

This regulation does not apply to;

  • An agricultural trailer; or 
  • A trailer mentioned in paragraph (b), (bb), (bc), (c), (d), (e), (f) or (g) of regulation 16(3) 

The following links provide guidance and further information