title: Analytical results of asymmetric exclusion processes with ramps.
abstract: We present the analytical results in a simple traffic model describing a single-lane highway with ramps. Both on-ramps and off-ramps are considered. Complete classification of distinct phases is achieved. Exact phase diagrams are derived. In the case of a single ramp (either on-ramp or off-ramp), the bottleneck effect is absent. The traffic conditions of congestion before the ramp and free-flowing after the ramp cannot be realized. In the case of two consecutive ramps, the bottleneck emerges when the on-ramp is placed before the off-ramp and the flow in between the ramps saturates.
authors.affiliation: Department of Physics, Chung Yuan Christian University, Chung-li, Taiwan.
authors.forename: Ding-wei
authors.initials: DW
authors.lastname: Huang