In the bus network case, provided thatticket machines should be available at the majority of stops, such solution might be quite expensive for launching, in particular in comparison with more modern ways like through website and mobile services, already available in a few capital cities. The only case can be that of Sofia and Bucharest, which can be considered peer cities. They have the same number of public transport options and although Sofia has relatively a little bit more accessible public transport network in terms of length and stations, it is Bucharest that achieves higher relative demand while offering on average more ticket purchase options. The compilation of several capital cities shows, at the same time, that the more rich cities offer more ticket purchase options (figure 2.28.),