Traffic jams induced by fluctuation of a leading car

We present a phase diagram of the different Binds of congested traffic trig gered by fluctuation of a leading car in an open system without sources and sinks. Traffic states and density waves are investigated numerically by va rying the amplitude of fluctuation using a car following model. The phase t ransitions among the free traffic, oscillatory congested traffic, and homog eneous congested traffic occur by fluctuation of a lending car. With increa sing the amplitude of fluctuation, the transition between the free traffic and oscillatory traffic occurs at lower density and the transition between the homogeneous congested traffic and the oscillatory traffic occurs at hig her density. The oscillatory congested traffic corresponds to the coexistin g phase. Also, the moving localized clusters appear just above the transiti on lines.