The most popular form of transport in Nairobi and other East African cities is called the matatu, a minibus with 12-25 seats. Some matatus operate along fixed routes, while other wait at one spot until they are full and then take their passengers to their destinations. Matatus are especially useful in East Africa, as they can penetrate areas impassable for larger buses. In 1982 Nairobi, a city of 750,000, had 1,550 matatus carrying 66,000 passengers a day. Although matatus have a reputation for speeding, they are still popular compared to decrepit public buses.

Source: Gabriel Roth and George G. Wynne. Free Enterprise Urban Transportation.