Analyzing the Structure of Informal Transport: The Evening Commute Problem in Nairobi, Kenya

In many parts of the world, particularly in developing countries, informal privately-operated transportation plays an integral role in people's mobility. This study systematically analyzes the development and structure of informal transit systems as a function of the network, user, and modal characteristics for an evening commute problem along a linear corridor where passengers originate uniformly from a central business district and have destinations uniformly distributed along the corridor. The model jointly takes into account user mode choice and operator fare and frequency decisions. Three types of operators each with different objectives are analyzed: (1) informal transit with competing operators, (2) a welfare-maximizing government, and (3) a private monopoly or company. Policies, such as fare regulation and vehicle licensing schemes, are presented to help rationalize private and informal transit service using a government-operated service as the baseline. The use of continuum approximation tools allow for a 2-D graphical representation of the regulatory environments. Using Nairobi, Kenya as a case study, it was concluded that with proper regulation and oversight informal transit can perform similar to publicly provided transit