New Road
 

Paddy was telling Mick about how he'd found several precious stones when laying tarmac on a new road in Limerick.
Mick "Was it a Motorway Paddy ?"
Paddy "No Mick, it was one o'dem new Jewel Carriageways"

...um, what?

I tried searching on Google, and "jewel carriageway" is a phrase that gets used, but I can't figure it out. I must be too American for this one.

I think the joke is that he meant to say "dual carriageway", which is a divided highway. It's a pun.