OT - Speed limits now in KM per Hours in Ireland
 

Speed limits will change from imperial to metric ie: from miles to
kilometres.
All new speed limit signs will display the metric value of the speed limit
together with the unit "km/h".

The general delimited speed sign ? will be abolished.

also watch out for the saftey ( speed) cameras and unmarked vascar equiped
police patrol cars

Have a look at http://www.ireland-salmon-fishing.net/Travel/speed.htm