see the market sizing question in the title of this post. Would it be a reasonable approach to extrapolate the KM of road in a country based on the assumption of KM of road / per capita of smaller villages?
My rationale would have been to think of 4-5 small villages close where I grew up in and estimate the KM of road based on my experience of running through these towns.
I then would come up with a KM roads / 1000 people figure and multiply that up to the number of total inhabitants. Additionally, one could make slight adjustment for the area/density as km of roads will not only be a function of people but also of the overall area.