Green’s Dictionary of Slang

(Irish) a taxi.

1994		J. O’Connor Secret World of the Irish Male (1995) 85: I seen him ownee the other night outside Lillie’s Bordildo and him being lurried into a joe maxi blue mowldy with the dhrink.
2000		P. Howard Miseducation of Ross O’Carroll-Kelly (2004) 77: Someone suggests [...] hopping into a Jo and heading out to Donnybrook.
2001		G. Coughlan Everyday Eng. and Sl. 🌐 Jo Maxi (n): taxi.
2005		P. Howard Curious Incident of the Dog in the Nightdress 73: I grabbed a Jo into town.