Transit agencies constantly need information about system operations and passengers to support their regular scheduling and operation planning processes. The lack of these processes and cultural motivations to use public transportations contributes enormously to the reliance on the private cars rather than public transportation, resulting in traffic congestions. The traffic congestions occur mainly during peak hours and the accidents happening as a result of road accidents and construction works.  This study investigates the effects of weekday and weekend travel variability on peak hours of the passenger flow distribution on bus lines, which can effectively reflect the degree of traffic congestion. A study of passenger traffic flow patterns during these times can impact planning decisions on transportation engineers. It can be viewed as a building block for generating a reliable schedule for a given bus route within the context of an optimization process.  Collecting data sets of a two-directional bus line in Sulaimani city, connecting a residential district to the city center, for three days (Wednesday, Thursday, and Friday), and this study analyzed the flow and distribution of weekday and weekend passenger movements along with the bus stops of each direction on-peak and off-peak periods. The results indicate that Thursday passenger volume is more similar to Friday passenger volume than on Wednesday passenger volume. The passenger volume of direction D1 (from the residential district to the city center) is double that of direction D2 (from the city center to the residential district). The maximum morning peak time is on Wednesday with 442 passengers/hr, starting from 7:30 to 9:00, and the maximum evening peak hour is on Thursday with 420 passengers/hr, beginning from 14:30 to 16:30.