Article 9 of the Road Traffic (Traffic and Parking) Regulation 1997 (SI 182 of 1997) specifies that vehicles should be driven on the left hand side of the roadway, in a manner that allows safe overtaking on the right. Article 10(4) of the Regulations further states that, other than in the circumstances prescribed, drivers shall overtake on the right. Failure to drive on the left and dangerous overtaking are currently penalty point offences as per the Road Traffic Act 2002.
Under the Road Safety Authority Act 2006 (No. 14 of 2006), the RSA has a key role in road safety promotion, education and awareness. To date, it has run a number of campaigns on the rules for driving on motorways and dual carriageways. In 2018, the RSA published a booklet specifically on motorway driving which contains a section on using lanes properly: www.rsa.ie/docs/default-source/road-safety/motorways/motorway-booklet-2018-web-(002).pdf?sfvrsn=850e47e3_3