In this paper，we apply a nonlinear map model to investigate the influences of signal light and position of bus-stop on the traffic at a T junction. The dependence of point-based average flow of routes on bus-stop position，signal light cycle and split as well as vehicle swerve are numerically analyzed. Simulation results show that the interaction between bus-stop and signal light generates traffic clustering easily，and there exist relationships between signal light cycle，split，bus-stop position and the route flows.