Underneath the surface recorded as a public road on the 1842 Ordnance Survey six-inch map lay a cobbled road of an entirely different era, its large stones tightly packed into a solid surface and its underlying ditches still holding their shape in the soil.

The road's construction followed a pattern that archaeologists recognise as a two-stage process. Two parallel fosses, that is, shallow ditches dug to define and drain a roadway, first established a narrow north-south trackway. The eastern fosse measured three metres wide and roughly forty centimetres deep; the western was somewhat narrower and shallower. At some later point the trackway was widened and the cobbled surface was laid over the top. The excavator, Cotter, identified what appear to be continuations of the same fosse system at two other locations in Ballinvinny South, suggesting the road extended for a considerable distance. One set of fosses, roughly 120 metres to the north, ran immediately to the south-west of a possible 16th or 17th-century house; another set, a further 80 metres north again, lay close to a metalworking site. Artefacts recovered from the excavations dated broadly to the 18th and 19th centuries, though Cotter argued the road belongs to a wider late and post-medieval settlement complex linking domestic structures and the metalworking site into a coherent landscape of activity.

What gives the Ballinvinny road its particular interest is the way it collapses the distance between different kinds of history. A working farm track, still functional enough to appear on a Victorian map, turned out to be the last layer of a sequence stretching back through the cobbled road, through the fosses beneath, to a settlement that included craft industry and domestic life across several centuries. The bypass revealed it; the road surface had, in effect, been preserving its own past.