This is a picture I took while in Ireland.
http://signsoflife.goose24.org/?sign=24In America when one says "who cares?" it's meant sort of sarcastically, which is obviously (I hope) not the case in Ireland. What perzactly does this mean?
Well I happen to have an Irish name, so I’ll have a go.
‘Who cares?’ Has the same ‘who gives a damn?’ meaning on this side of the Atlantic. The sign is to attract attention and make you think. On the one hand, perhaps drivers who are still being careless are displaying a ‘Who cares’ attitude, on the other hand if you answer the question with the inward thought ‘I do’, then you will drive more carefully after seeing the sign; at least until you are out of Westmeath!
The explanation above is spot-on. There is no regionalism here, just a way of attracting attention by using a phrase that on the face of it is utterly inappropriate (the dominant meaning is a rhetorical way of saying "nobody cares; it is of no importance"), but has a second, literal meaning that is a query or a challenge to the reader.
Ted, ohmigawd, some of these are priceless! How'd you ever find that site? Oh, never mind, I forgot who I was speaking to. I think the one "next" to yours is just about my favorite (the monolith); I also like the Japan one where there is apparently no way to meet the deadline, and I love the monkey one, esp. the drawings. Must confess that I first interpreted "Signal Turns When Speeding" meant that it must be okay not to signal your turns when you're not speeding!