Sub-Roman Britain (Cavalry etc)

[Alanus]

I imagine these roads had a cleared area to each side to discourage robbers and ambush. Like you say, a contingent of cavalry could navigate the shoulders at a fairly good clip. Once again, I'm thinking that the post-Roman Britons did not have a standing army, ie foot; but a group of semi-professional horsemen representing various small kingdoms seems feasable... and this is exactly what has come down to us in the old songs and later medieval material.