When I was already back in Switzerland, I heard that one of my Ghanaian friends had just had a very bad car accident with a Trotro. While driving with her passenger car to the farm where she was the manager, she had collided with a reckless Trotro driver. While she was only slightly injured, the Trotro had been irreparably damaged, and the entire busload of passengers had been seriously hurt.
I guess this is the the drawback of self-organization, in that each Trotro driver wants to maximize income for himself by driving as rapidly as possible. On the balance between public good and optimizing his own gain, this driver tried to tip the scale too much towards himself, with very bad consequences for himself and his passengers.