Trailer weight limits part of new RSA standards

New national trailer weight limits will be among a number of new vehicle standards take effect for agricultural vehicles from 2016 and will also include braking, lighting and visibility among others.

The new standards are being introduced following a comprehensive review, including a public consultation, undertaken by the Road Safety Authority (RSA) over a prolonged period since 2008 which examined the current legislation, policy and practice relating to the use of agricultural vehicles on public roads.

The current regulations are in place for more than half a century, during which time agricultural vehicles have become bigger, faster and more powerful, and their use has been expanded to include a wide variety of tasks outside the scope of the current regulations. Agricultural vehicles are now widely used on our roads and they are generally constructed to very high standards. The proposed changes to the regulatory regime reflect developments in agricultural vehicle technology and require them to comply with recognised vehicle standards in relation to critical road safety areas, i.e. braking, suspension systems, tyres and lighting as well as the weights for which the vehicles are designed.

The majority of correctly maintained tractors already in use comply with the revised standards being introduced. Those that do not comply are likely to need only minor remedial works carried out such as fitment of a flashing amber beacon and/or a replacement manufacturer’s plate indicating their design axle weights and maximum permitted towable masses.

A summary of the improvements applying from January 1, 2016 is as follows:


More powerful braking systems will be required for agricultural vehicles operating at speeds in excess of 40km/h. Most of the correctly maintained tractors which have come into use in the past 30 years already meet these requirements.
Agricultural vehicles will need to be equipped with appropriate lighting systems, flashing amber beacons and reflective markings.

Trailers operating at weights exceeding 19 and 22.5 tonnes for tandem and triaxle trailers respectively, or at speeds exceeding 40 kilometres per hour, will require fitment of both a weights and dimensions plate and a speed disc.

New national weight limits are being introduced. These will enable tractor and trailer combinations which are unplated to continue in use at limits which are safe for such vehicles, i.e. combinations of agricultural tractors and trailers, where either of them is unplated, will have their maximum towable mass capped at 3 times the tractor’s unladen weight. Plated tractors and trailer combinations will benefit from being able to operate at higher weight limits of up to 24 and 34 tonnes for tandem and triaxle agricultural trailers respectively that meet certain additional requirements:, i.e. they must be plated, they must be fitted with a flexible suspension system, they must be fitted with flotation tyres for operation at 10 tonnes per axle in the case of a tandem axle trailer or 9 tonnes per axle in the case of a triaxle trailer, and finally they must be fitted with a steered or steering axles if they have an axle spacing of 1.8 metres or greater.

Exemptions from compliance with the revised national weight limits and plating requirements are being provided for certain types of interchangeable towed equipment such as slurry tankers, manure or fertiliser spreaders and grain chaser bins.


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