Most naive operators opt for hiring a driver for fixed wages, since the prospective profit is greater. This is why they usually fail: a wage employee has no incentive to maintain the vehicle or to be honest with the takings. … The most secure method is to sell the vehicle to the driver on an instalment plan and make him responsible for maintenance, a method pioneered in Ghana by Lebanese traders.

XREF: Ties to principal-agent theory and incentive design in economics; parallels modern questions about gig-economy versus salaried labor incentives.

Diego Gambetta, Trust - Making and Breaking…, loc. 2366