The fact that Johannesburg is not near a large navigable body of water has meant that ground transportation has been the most important method of transporting people and goods in and out of the city. One of Africa's most famous "beltways" or ring roads/orbitals is the Johannesburg Ring Road. The road is composed of three freeways that converge on the city, forming an 80-kilometre (50 mi) loop around it: the N3 Eastern Bypass, which links Johannesburg with Durban; the N1 Western Bypass, which links Johannesburg with Pretoria and Cape Town; and the N12 Southern Bypass, which links Johannesburg with Witbank and Kimberley.
The N3 was built exclusively with asphalt, while the N12 and N1 sections were made with concrete, hence the nickname given to the N1 Western Bypass, "The Concrete Highway". In spite of being up to 12 lanes wide in some areas, the Johannesburg Ring Road is frequently clogged with traffic. The Gillooly's Interchange, built on an old farm and the point at which the N3 Eastern Bypass and the R24 airport Freeway intersect, is the busiest interchange in the Southern Hemisphere. It is claimed that the N1 is the busiest road in South Africa.
Johannesburg has the most freeways connected to it. It has the N1, N3, N12, N14, N17, R21, R24 and the R59, all leading to Johannesburg. The M1 and M2 freeways were built to direct traffic towards the city centre. These two freeways are congested due to mass urbanisation.
Johannesburg shares a network of metropolitan routes with Krugersdorp and Ekurhuleni.