When Were Roman Military Roads Built

[Robert Vermaat]

I suspect that some of the Iron age "Roman" roads in Britain were in part native British built and simply improved and incorporated into the larger Roman road network built to accommodate the greater traffic demands of the empire.

Amen to that. Also, Roman roads were not always the heavy constructions with aggers and layer upon layer of material. Here in The Netherlands the Limes road was found to be a sometimes very thin layer of gravel - no doubt due to the terrain which along the Lower Rhine can be very thin. Small wonder archaeologists searched for it for a long time. But such a thin layer of gravel would have been very easy to get in place. maybe the 'improvement' of earlier Iron Age roads would have been easy and quickly done, before the 'real' roadbuilding took off.