Length & Width

The road traffic regulations make very detailed provisions in respect of all matters affecting vehicles, trailers, track laying devices, tractors.  There are provisions for special permits for the use of vehicles or trailers which might otherwise breach the regulation.

The maximum weight and dimensions of vehicle is specified. Subject to conditions the width of a vehicle must not generally exceed 2.5 m. Public service vehicles may be slightly larger. Combinations of agricultural vehicles and trailers under certain circumstances may be wider. Certain things are excluded and included for the purpose of measuring width.

There are limitations on the length of vehicles and vehicle combinations (vehicle with trailer). The maximum length depends on the class of vehicle (e.g. public service vehicle). Greater lengths are subject to specific conditions.

There are provisions in respect of the overall width of vehicles.  Certain items are disregarded such as mirrors, custom seals, retractable steps etc.

There are detailed provisions in respect of trailers.

Rules on Weight

Regulations may specify the unladen weight of vehicles either alone or in combination. They may relate to the pressure transmitted to the ground. Regulations may make different provision for diverse types of vehicles in different circumstances. The regulations make provision for laden and unladen weight for various classes of vehicle.

The owner, user or consignor of the vehicle may be prosecuted. There is fixed charge penalty of €200 if paid within 28 days, and on summary conviction a fine of up to €2,000 and or imprisonment three months.

There are mandatory penalties for excess weight over 17,000 kg laden. Penalties are payable to the roads authority. The authority may recover damages in which event the penalty is reduced accordingly.

The mandatory penalties are with reference to the excess over the maximum permitted laden weight. There are detailed regulations in respect of weight relative to several factors such as the number of axles and the distance between them

Certain vehicles must display a certificate or plate with their weight unladen if they are in a public place. Contravention is subject to €1,000 fine on summary conviction or up to 3 months imprisonment or both.

A person may be required to pay extraordinary expenses incurred by a road authority due to extraordinary traffic. An agreement may be entered for payment of a sum in  composition. Proceedings may be commenced generally within 12 months of when the damage is done. They may be recovered in the High Court or concurrently in the Circuit Court.

The local authority, road or canal authority or other person or entity obliged to maintain a bridge may place notices restricting the weights of vehicles which may use it. Users affected may appeal to the Minister/Department who may give the appropriate directions.

It is an offence to drive a vehicle or a combination of vehicles over a bridge in contravention of the notice. The owner is liable to pay the authority or entity maintaining the bridge damages accordingly.

Maximum weights may be specified for vehicles using the road by way of the relevant road sign specifying maximum weight vehicle


There is a maximum permissible drive axle weight of a vehicle of 11.5 tonnes and a maximum laden weight.  The heaviest configuration for articulated vehicles with trucks and trailers having six or more axles is generally 44 tonnes subject to certain protections regarding construction, design, brakes, etc.

The Road Traffic Act allows the Minister to make regulations specifying maximum weight of vehicles laden and unladen.  It may specify the maximum weight that may be transmitted to the ground or any specific area of the ground by wheels, etc.  Different regulations may be made for different vehicles or combinations of vehicles.

It is an offence to use a vehicle in breach of the weight regulations.  The owner or the consignor loading the goods may be guilty.  Fixed charge penalties may be used.

Special Weight Controls

Special permits are permitted for certain vehicles which would otherwise contravene the regulations. The Road Traffic (Specialised Vehicle Permits) Regulations,  introduced a system of permitting, administered by the Gardai  for the movement of wide and long vehicles not exceeding 27 metres in length and 4.3 metres in width on major interurban routes.

Certain vehicles may not be used in a public place without a certificate and a plate indicating maximum weights for which they are designed.  Manufacturer plates may be present but if they are not in certain circumstances substitute weights plates must be provided.

The unladen weight of a vehicle or a combination of vehicles is to be taken as the weight of the vehicle including all additions but exclusive of water, fuel, or accumulators other than boilers used.  Additions include any body, part, fitting, or receptacle.

Where an authorised officer observes a vehicle or a combination of vehicles which may exceed the maximum weights,  they may be required to be weighed at an appointed weigh bridge within 25 kilometres.  Breach of the requirements  in respect to weighing is an offence subject to a fine of up to €2000 and up to three months imprisonment.

Road authorities may provide traffic weighbridges and mobile weighbridges for use by An Garda Siochana.  There are extensive powers for authorised officers to monitor compliance.Every road party owning a weighbridge must maintain it in good order, repair, and ensure that it is accurate.  A road authority may charge for weighing of vehicles.

There are certain obligatory penalties which must be paid to the road authority responsible for the road maintenance or if certain weight offences are committed.

The authorities have power to recoup expenditure on maintenance of roads caused by extraordinary traffic.  This applies where extraordinary expenses have or will be incurred in repairing the road by reason of damage caused by excessive weight passing along the road or other extraordinary traffic.  The sum is recoverable as a debt.

Local authorities, railways or other such companies may protect bridges from undue burdens by limiting the weight or types of vehicles that they may pass over them.  A notice may be exhibited.


A person may not use certain categories of vehicles in a public place unless there is a plate exhibited setting out the maximum weights, not to be exceeded in the case of vehicles or combinations of vehicles.  A person may not use such a vehicle unless there is a certificate indicating the maximum permissible weight.  Application may be made to the authority for a plate and certificate. The licensing authority may determine the maximum weights, which are not to be exceeded in the case of a vehicle or combination of vehicles.  Regulations may provide for exemptions.

Authorised officers may inspect and examine vehicles for the purpose of ascertaining compliance with the above provisions.  Owners may be required to submit to examination on the spot in public places.  Failure to cooperate is effectively an offence.

The Minister may make regulations designating markings to be applied to vehicles or vehicle parts in accordance with international agreements.

There is provision for imposition of fixed penalties where persons are convicted of using vehicles in excess of certain maximum laden weighs.  There is a table of fixed penalties apart from the penalty which may be imposed by law.  The penalty is graduated for €500 up to €5,000 depending on the excess weight

Lighting and Reflection

There are detailed requirements in respect of lighting of vehicles.  Light, lamps and reflectors must be maintained.  They must comply with the detailed provisions of the legislation.

There are requirements in respect of mirrors and reflectors. There are obligations in respect of reflectors.  There are also restrictions on unauthorised reflectors and detailed sizes, locations, etc. and compliance requirements by reflectors.

Vehicles of various classes must have lights and reflectors of certain types. They must work and be used. Certain lights are required for signalling. Brake lights are required.

Lights and reflectors must be fitted and maintained in good working order and capable of use. Internal lights are required. There are detailed requirements regarding the colour positioning and effectiveness of lights.

The identification marks must be illuminated There are minimum requirements for lighting. It is an offence to use  vehicles not equipped with the required lighting. Equipment obligations apply in respect of trailers. There are requirements in respect of reflectors.

There are  obligations to have lights switched on during lighting up hours or when atmospheric conditions cause reduced visibility, or they are otherwise so required.

The requirements to use lighting in some cases when a vehicle is stationary. Lighting may be required if the vehicle is a danger to traffic and is not visible. The requirements lighting does not apply provided certain conditions are met including g proper lighting in the vicinity and proper parking

There are detailed specific requirements for agricultural tractors and trailers.

There are requirements in respect of lighting, colour, flashing lights, movement, dips etc. There are certain exemptions for certain classes of vehicles as used during daylight other than on a public road.

Reflection fluorescent marking are required in respect of some vehicles.  There is a requirement for a long vehicle sign.

There are requirements in respect of trailers.  There are more detailed provisions in respect of small and large public service vehicles.  There are detailed provisions in respect of side lamps, spot lamps, markers, identification mark lighting, headlamps and rear projector lamps lighting.

Further Regulations

In addition to regulations specifying approved types of vehicles there are specific requirements in respect of the following. The regulations specify detailed requirements in respect thereof

  • sufficient steering mechanism
  • mud wings
  • reversing gear
  • full view of the road
  • safety glass in windscreens
  • windscreen wipers
  • mirrors
  • speedometers
  • horn/audible warning device
  • silencer
  • means to prevent unlawful driving
  • controls on emissions of noxious material
  • exhaust fumes
  • no inessential projections or objects


There are requirements in respect of brakes and brake performance. Brakes must be able to bring the vehicle to a stop within certain distances at certain speeds. Some vehicles require an emergency brake.

Nuisance / Noise

Noise suppressors are required under the general vehicle regulations above.

A vehicle may not be used with a loudspeaker/public address system save with limited exceptions linked to

  • elections
  • emergency services
  • pursuant to a special permit from local authority

It is an offence to sound an audible warning except when reasonably necessary on the grounds of safety. There are additional restrictions between 11:30 PM and 7 AM in urban areas, other than where it is necessary to avoid immediate danger. There are offences regarding emissions of fumes.


There are detailed provisions in respect of trailers. There are minimum and maximum distance of separation and requirements in respect of attachments. There are detailed requirements applicable to trailers in terms of suspension wheels lighting  construction et cetera

The Minister may make regulations for the control and operation of vehicles drawn by mechanically propelled vehicles, i.e. trailers.  They may provide for

  • licensing of such vehicles,
  • payment of specified fees
  • plates,
  • conditions of use,
  • keeping of records
  • production of certificates.

Breach of such regulations is an offence.


Important Notice! This website is provided for informational purposes only! It is a fundamental condition of the use of this website that no liability is accepted for any loss or damage caused by reason of any error, omission, or misstatement in its contents. 

Draft Articles; The articles on this website are in draft form and are subject to further review for typographical errors and, in some cases, updating and correction. It is intended to include references to the sources of materials and acknowledgements in the final version. The content of articles with [EU] in the title and some of the articles in the section on Agriculture are a reproduction of or are based on European or Irish public sector information.

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