2 research outputs found
Two-way traffic flow: exactly solvable model of traffic jam
We study completely asymmetric 2-channel exclusion processes in 1 dimension.
It describes a two-way traffic flow with cars moving in opposite directions.
The interchannel interaction makes cars slow down in the vicinity of
approaching cars in other lane. Particularly, we consider in detail the system
with a finite density of cars on one lane and a single car on the other one.
When the interchannel interaction reaches a critical value, traffic jam
occurs, which turns out to be of first order phase transition. We derive exact
expressions for the average velocities, the current, the density profile and
the - point density correlation functions. We also obtain the exact
probability of two cars in one lane being distance apart, provided there is
a finite density of cars on the other lane, and show the two cars form a weakly
bound state in the jammed phase.Comment: 17 pages, Latex, ioplppt.sty, 11 ps figure
Phase diagram of congested traffic flow: an empirical study
We analyze traffic data from a highway section containing one effective
on-ramp. Based on two criteria, local velocity variation patterns and expansion
(or nonexpansion) of congested regions, three distinct congested traffic states
are identified. These states appear at different levels of the upstream flux
and the on-ramp flux, thereby generating a phase diagram of the congested
traffic flow. Compared to our earliear reports (including cond-mat/9905292)
based on 14 day traffic data, the present paper uses a much larger data set
(107 days) and the analysis is carried in a more systematic way, which leads to
the modification of a part of interpretation in the earlier reports. Observed
traffic states are compared with recent theoretical analyses and both agreeing
and disagreeing features are found.Comment: More extensive and systematic version of earlier reports (including
cond-mat/9905292). A part of interpretation in earlier reports is modified. 6
two-column pages. To appear in Phys. Rev. E (tentatively scheduled for Oct. 1
issue