title: Comment on "Cellular automata model simulating traffic interactions between on-ramp and main road".
abstract: In a recent study of traffic flow around on-ramp [R. Jiang, Q. S. Wu, and B. H. Wang, Phys. Rev. E 66, 036104 (2002)], two different types of phase diagrams are reported: four distinct regions are observed in the cases of v(max)>1, while only two regions are present in the case of v(max)=1. We point out that the characteristics of the phase diagram are totally dictated by the prescribed asymmetric rule of the on-ramp. In the congested phase (region IV), the configurations evolve as stable limit cycles, and are independent of v(max). The saturated currents can be obtained analytically.
authors.affiliation: Department of Physics, Chung Yuan Christian University, Chung-li, Taiwan.
authors.forename: Ding-wei
authors.initials: DW
authors.lastname: Huang
authors.forename: Wei-neng
authors.initials: WN
authors.lastname: Huang