From here, the practical info, and everything you need to know, to drive in Ireland without problems.

As always, it is recommended to follow some basic and universal rules.
Always respect speed limits. The checks are more and more frequent. A fundamental principle for safety and, also, for your pockets; avoid heavy fines.
If you have drunk alcohol, DO NOT DRIVING. For no reason.
In the event of an accident, YOU MUST ALWAYS STOP and provide assistance.

BASIC RULES TO DRIVE IN IRELAND

In Ireland you drive on the left and overtake on the right. Always respect the safety distance.

Always give priority to pedestrians who cross or are about to cross a road; even if there are no pedestrian crossings on the ground.

Infrastructure is far from efficient. Some roads, especially the secondary ones, are in poor condition. Sudden holes, poor lighting are the order of the day. It is invited, precisely on this trait, to the utmost attention.

DOCUMENTS TO DRIVE IN IRELAND

Driving license, registration certificate and valid insurance certificate. If you are driving a vehicle that is not your own, we recommend that you take a DELEGATION TO CONDUCT. This is a delegation of the vehicle owner with an authenticated signature.

VEHICLE EQUIPMENT

It is mandatory to have a triangle in the car. The seat belts must necessarily be fastened on all the seats provided.

ROADS AND SIGNS

Photo, 2007 Sarah777

The letter M, followed by the numbers, indicates that you are in the presence of a motorway. The highway signs have white characters on them BLUE BACKGROUND.
Remember that all motorway sections are tolls.
The letter N, followed by a sequential number from 1 to 50, indicates instead National primary roads, that is, the national primary roads. They are marked with signs a GREEN BACKGROUND and white character.
Progressive numbers from 59 upwards that follow the letter N, indicate the National secondary roads, that is, the secondary roads. It is a cross between the main roads and the regional roads.

The indications, except for some minor traits, are all bilingual: English and Gaelic. Borders and distances are reported differently, depending on the area. In the Republic of Ireland, they are expressed in kilometers. In Northern Ireland, in miles.

SPEED LIMITS

Unless otherwise specified, the limits to be met to drive in Ireland are as follows:

50 km/h on urban roads
80 km/h on non-national extra-urban roads (regional and local)
100 km/h on national extra-urban roads
120 km/h on the highway