Braking

Changes to the Braking Requirements for Agricultural Vehicles.

Introduction

Agricultural vehicles, especially those capable of operating at speeds exceeding 40km/h, must be fitted with safe and efficient braking systems to address the potentially serious road safety risks associated with using “under braked” trailed equipment on public roads, i.e. premature tractor brake wear or failure leading to the possibility of jack-knifing.

Trailed agricultural equipment must also be correctly matched for the intended speed and load being drawn, and that such equipment is routinely maintained if tractor brake failure is to be avoided.

In order to address these issues, revised braking requirements will apply to agricultural tractors and their trailers (both new and existing) from 1st January 2016. 

Note that the term agricultural trailer refers to those trailers drawn behind agricultural tractors which are being used for agricultural, fisheries, forestry or horticultural purposes; and includes pieces of interchangeable towed equipment where the ratio of the Design Gross Vehicle Weight (DGVW) to the unladen weight is equal to or greater than 3.0. DGVW is the maximum laden weight as specified by the manufacturer.

Therefore the revised braking requirements, in addition to applying to agricultural trailers, also apply to equipment such as slurry tankers, fertiliser or manure spreaders and grain chaser bins etc. For example a slurry tanker with a maximum laden weight of 20 tonnes and an unladen weight of 6 tonnes must comply with the revised braking requirements outlined below, i.e. due to the fact that the ratio of the maximum laden weight to the unladen weight (i.e. 20/6) is 3.33.

Revised Requirements for Agricultural Tractors

Agricultural tractors which are already in service, provided their braking systems are correctly maintained, will already comply with the revised braking requirements outlined in Table 1 below.

A summary of the minimum tractor braking performance requirements expressed as percentage efficiencies (i.e. braking effort as a percentage of the tractor’s Design Gross Vehicle Weight (DGVW)) are included in Table 1 below. These will apply to both new and existing agricultural tractors from 1st January 2016.

Minimum Braking Performance Requirements for Agricultural Tractors

Speed rating less than or equal to 40km/h

Speed rating greater than 40km/h

Service Brake (25%)
Parking Brake (16%)

Service Brake (45%)
Emergency Brake (22.5%)
Parking Brake (16%)

Table 1: Revised Agricultural Tractor Braking Standards Applicable from 1st January 2016.

Revised Requirements for Agricultural Trailers

Agricultural trailers which are already in service, due to the wide variation in construction standards, may need remedial works carried out to achieve compliance; particularly if it is intended to draw them at speeds exceeding 40km/h.

A summary of the minimum trailer braking performance requirements, once again expressed as percentage efficiencies, are included in Table 2 below. Note that the figure quoted for the service brake performance is based on the weight transmitted to the road surface by the trailer axle(s) fitted with brakes, whereas the breakaway and parking brake performances quoted are based on the Design Gross Vehicle Weight (DGVW) of the trailer. These will apply from 1st January 2016.

 

Minimum Braking Performance Requirements for Agricultural Trailers

Trailers with a speed rating less than or equal to 40km/h and a Design Gross Vehicle Weight (DGVW) exceeding 5,000kg.

Trailers with a speed rating greater than 40km/h and a Design Gross Vehicle Weight (DGVW) exceeding 3,500kg.

Service Brake (25%)
Breakaway Brake (13.5%)
Parking Brake (16%)

Service Brake (45%)
Breakaway Brake (13.5%)
Parking Brake (16%)

Table 2: Revised Agricultural Trailer Braking Standards Applicable from 1st January 2016.

Furthermore all agricultural trailers which are manufactured from 1st January 2016 and are capable by design of being drawn at a speed exceeding 40km/h must be equipped with:

  • pneumatic braking systems (including load sensing functionality which matches the service brake effort to the weight of the load being carried); and those capable of being drawn at a speed exceeding 60km/h must also be equipped with antilock braking systems (ABS).
  • a breakaway brake capable of automatically stopping them should they become detached from the tractor while in motion.

However agricultural trailers manufactured prior to 1st January 2016 (provided they are incapable by design of being drawn at a speed exceeding 40km/h) may alternatively be fitted with a secondary coupling consisting of a chain or wire rope.

Agricultural trailers and interchangeable towed equipment manufactured prior to 1st January 2016 which are capable by design of being drawn at a speed exceeding 40km/h and which are not fitted with a breakaway brake have until 1st January 2016 to achieve compliance.

Finally, overrun braking systems, where fitted to lower speed custom-made agricultural trailers or pieces of interchangeable towed equipment with a Design Gross Vehicle Weight (DGVW) not exceeding 5,000kg, must be capable of generating minimum service and parking brake efforts of 49% and 16% respectively. These figures are based on the Design Gross Vehicle Weight (DGVW) of the vehicle.

If you are unsure as to whether your vehicles comply with these revised standards, we recommend you contact the vehicle manufacturer or their authorised distributor for advice. Some practical advice, including more detailed explanations of the braking related terminology referenced above, is contained in our list of braking related ‘Frequently Asked Questions’.