Automatic Passenger Counting (APC) solutions imply different ways of counting passengers and the most common division of APC is on independent and integrated systems. This chapter analyzes independent passenger counting solutions based on Wi-Fi technology. In this chapter, the researched problem is reflected in the review of different approaches to ridership via Wi-Fi technology in Public Urban Passenger Transport (PPT), and the most common possible division is on active and passive scanning of mobile user devices for probe request frames. Passenger counting using Wi-Fi-based APC in urban traffic can be broken down (classified) according to several observation factors, such as the location of the counting (inside and outside the vehicle), the observed means of transport (bus, train/metro, etc.), and the purpose of the collected data, estimates, actual numerical values, and methods/methodology of passenger counting. This chapter can serve as a contribution to defining the taxonomy of the way passengers are counted using Wi-Fi technology in different subsystems of public urban passenger transport as a part of future development or ongoing integration into a Smart City concept.