In the last decade, many paper focused on describing vehicular traffic stream of an arterial on an aggregate level. Unfortunately, among this considerable body of research, only few papers account for bus systems. Our paper tries to fill this gap by investigating two potential methods to estimate macroscopic fundamental diagrams of multimodal transport systems of a signalized arterial. The first approach models endogenously motion of bus by extending the work by the moving bottleneck theory, whereas the second approach proposes to incorporate exogenously effects of buses. The estimated macroscopic fundamental diagrams are then cross-compared to results provided by micro-simulation software that finely reproduce traffic stream. It turns out that mean speeds of vehicles and buses produced by the different methods are similar and consistent. Finally, results of the three methods are expressed in terms of levels of service and confronted with the levels of service of the HCM2010.