Many Irish roads are currently busy with farmers and contractors travelling in agricultural vehicles completing important tasks when possible.

With hay and silage being cut in some counties and crop harvests underway, roads with tractors, trailers, and combine harvesters are now a common sight.

The Road Safety Authority (RSA) has provided the maximum dimensions that agricultural vehicles are permitted to be while on the road in the table below.

Type of agricultural machineryMaximum widthMaximum lengthMaximum height
Agricultural tractor2.55m12m4.65m
Agricultural trailer2.55m12m4.65m
Large tractor (ie. unladen weight exceeding 7.25T)2.75m12m4.65m
Tractors with flotation tyres or dual wheel systems3.5m12m4.65m
Fully mounted equipment and interchangeable towed equipment3m12m4.65m
Self-propelled agricultural machinery3.5m12m4.65m
Agricultural tractor and trailer combination2.55m18.754.65m
Dimensions for agricultural vehicles Source: RSA

The 4.65m limit applies to all agricultural vehicles/combinations of vehicles except those transporting agricultural baled produce (i.e. hay, silage straw or other animal fodder) which has no height limit.

The RSA stated there is no height limit for baled produce. However, the load must not exceed the vehicle’s design gross vehicle weight and/or individual axle weight limits.

In addition, under road traffic law, the bales must be properly loaded so that they are not liable to fall off, drag or cause danger to other road users and the load must be distributed in such a way that it is not likely to destabilise the vehicle.

The 2.55m limit excludes the part of flotation tyres and mudguards protruding beyond the bodywork, up to a maximum of 100mm on each side of the vehicle, and devices associated with hydraulic rear door opening mechanisms.

Self-propelled agricultural machinery can be wider than 3.5m so long as when travelling on public roads it has an escort vehicle, flashing amber beacons and a ‘CAUTION – WIDE LOAD FOLLOWING’ sign.

Number of axlesAxle spacingNational weight limit
2N/A18t
3N/A24t
Weight limits for agricultural tractors Source: RSA

Combinations of agricultural tractors and trailers, where either of them is unplated are not allowed to tow more than three times the tractors unladen weight.

Below are the limits for agricultural trailers:

You need to apply for an abnormal loads permit from either an Garda Síochána or the local authority, or in some cases both.

An Garda Síochána permit applies to loads not exceeding 27.4m in length and 4.3m in width on designated roads.

All other abnormal loads require a local authority permit.