"Níl an mótarbhealach ar an léarscáil."
Translation:The motorway is not on the map.
Freeway? Expressway? I think it's one of those highways meant for only fast traffic (no bicycles and no hitchhikers sort of thing.)
"Motorways" are "highways" but not all "highways" are "motorways".
Motorways are "controlled access highways". Your Route 17 is a highway, but it's not a mótarbhealach.
US English doesn't really have an unambiguous term for a controlled access highway - Freeway, expressway, parkway, thruway and interstate are all common terms, but there are plenty of examples of stretches of controlled access highway around American cities that aren't given a specific label.
"There is no motorway on the map" - níl aon mhótarbhealach ar an léarscáil
"The motorway is not on the map" - níl an mótarbhealach ar an léarscáil
an mótarbhealach means "the motorway".