From OpenStreetMap Wiki
| Johannesburg, Gauteng, South Africa|
|latitude: -26.11, longitude: 28.058|
|Browse map of Johannesburg 26°06′36.00″ S, 28°03′28.80″ E|
|Use this template for your city|
In general, road coverage is good for the city but there are roads missing north of the city, you can add them using Bing imagery.