Wasn't there one in Ballymun, at least before the regeneration???
Under the Dart at Lansdowne Rd Station. Under the railway at Killiney, and at Greystones...clutching at straws there...
There's one in Blanchardstown that runs from the Snugborough Road, under the roundabout just north of the N3 bridge, then underneath the N3 itself and emerges in Blanch village. From the map it looks like it's what remains of the Old Corduff Road, from before the N3 dual carriageway was built back whenever (late '80s?).
World's most unsuccessful urban design element. Watch a film called Irréversible to learn everything you need to know about underpasses.
* Wilton Roundabout / Shopping Centre in Cork, but I think it is closed / demolished. Marked on this map http://www.corkcity.ie/maps/maps/41.html
I've a vague suspicion there may be one in Midleton, could well be wrong.
I think its a proper underbridge. Between the river and the roundabout.
Is it Mother Hubbards in Mullingar? They have a service area on the bypass, with petrol stations both sides, but the restaurant on one side.
Also, for cattle underpasses, there be hundreds of 'em.
Under the railway at Killiney
Actually, this one does count as it is under both the railway and the road - for access to the beach. It is however vehicle accessible, making it another 19th century road over road.