Answer
The categorisation of roads is helpful to road authorities as well as to road users.
Road authorities
Categorisation of roads allows road authorities to ensure efficient traffic flow in their management areas: through-traffic between two residential areas, for example, needs to be directed to a through-road as quickly as possible. Furthermore, the categorisation of roads provides handles for the design (features and layout) of the roads.
Road users
In principle, categorisation of roads is also helpful to road users. It is essential that roads with different functions have a consistent layout (recognisability). This way, road users will know how they are expected to behave, which other road users they can encounter and how these are likely to behave (predictability).
