Pietermaritzburg, like most South African cities, uses Metropolitan or "M" routes for important intra-city routes, a layer below National (N) roads and Regional (R) roads.
Each city's M roads are independently numbered.
[1] In South Africa, Metropolitan or "M" routes are mostly used in metropolitan municipalities and Pietermaritzburg is the only exception whereby it is not part of a metropolitan municipality yet still uses these road designations.
[2]