A time-headway model is presented to mimic bus behavior on the bus route. T
he motion of a bus is described in terms of the time headway between its bu
s and the bus in front. We study the bunching behavior of buses induced by
interacting with other buses and passengers. It is shown that the dynamical
phase transitions among the inhomogeneous bunching phase, the homogeneous
free phase, the coexisting phase, and the homogeneous congested phase occur
with varying the initial time headway. We study the effect of not stopping
at bus stops on the time-headway profile. It is found that the bunching tr
ansition lines are consistent with the neutral stability curves obtained by
the linear stability analysis.