Yes, Jefferies' description of the Ridgeway also crossed my mind. I wonder how big herds and flocks of cattle, pigs and sheep actually were four and a half thousand years ago? The Ridgeway is wide for purely human traffic, so too are the Avebury Avenues. I think Moss is right - it's a mistake to look for a one-fit answer to everything. The time-span is immense for starters: cursuses may have served different functions at different times, and that again may have varied in different parts of the country. The Chelmer Cursus seems to suggest a livestock function. The Stonehenge Cursus was perhaps more ceremonial. Who knows what the Dorset Cursus was for.