Carsten,
Regarding the taxis in Accra Ghana (I have visited their often and travelled in a number of taxis).

- The taxis are 20 - 35 year old used imports, many Toyota Carinas, Corollas and Starlets
- The vast majority are in poor condition and unroadworthy to a greater or lesser degree.
-The air-conditioners never seem to be in working order.

BUT

Pretty much everyone can afford these taxis, and the system works. somehow, even if it takes 2 hours to get from one side of Accra to the other.

Having said that, I like Accra, and the warm, welcoming Ghanaians.

Pointe Noire Congo and Brazzaville are even more taxi oreientated - there are more taxis on the road than "ordinary" cars and trucks.