Wide Jams Research Articles

Simon–Gutowitz bidirectional traffic model revisited

The Simon–Gutowitz bidirectional traffic model [P.M. Simon, H.A. Gutowitz, Phys. Rev. E 57 (1998) 2441] is revisited in this Letter. We found that passing cars get stuck with oncoming cars before returning to their home lanes. This provokes the occurrence of wide jams on both lanes. We have rectified the rules for lane changing. Then, the wide jams disappear and the revisited model can describe well the realistic bidirectional traffic.

EFFECTS OF PASSING LANES ON HIGHWAY TRAFFIC FLOW

In this paper, the effects of passing lanes on traffic flow on a single-lane highway are investigated based on a cellular-automaton (CA) model proposed by Lee et al. (2004) with periodic boundary conditions. A new driving strategy for the diverging and interacting processes are proposed by considering dual-time-headways (an interaction headway and a safe headway) as the criteria for a vehicle to select a lane or change lane. The proposed dual-headway rule has a clear physical sense and can be calibrated in the real world. We can see that (i) At low- (or high-) densities, there are no obvious increases of flux due to very weak (or very strong) interactions between vehicles. However, flux has an obvious increase at intermediate-density regions with the increase of the length of a passing lane; (ii) the space-time patterns before a passing lane are different from that after a passing lane, which is caused from vehicular reconfigurations on a passing zone; (iii) passing lanes can merge several narrow jams into one or few wide jams when increasing the length of passing lanes; (iv) if vehicles are allowed to travel with even higher speed, traffic can be further improved.

MODIFIED COMFORTABLE DRIVING MODEL FOR CONGESTED TRAFFIC FLOW

In this paper, the concepts of "jammed status" and "jam headway" [X. B. Li, R. Jiang and Q. S. Wu, Phys. Rev.E68, 016117 (2003)] are introduced into the Modified Comfortable Driving (MCD) model [R. Jiang and Q. S. Wu, J. Phys.A36, 381 (2003)] to simulate the congested traffic flow including synchronized flow and wide moving jams. Using computer simulation, the fundamental diagram, the space–time plots, the time series of the density in the jams, the 1-min average data in the flow-density plane, the traffic patterns induced by red light are investigated. It is shown that the new model can describe both the synchronized flow and the sparse wide jams quite well.

Single-vehicle data of highway traffic: microscopic description of traffic phases.

We present a detailed analysis of single-vehicle data, which sheds some light on the microscopic interaction of the vehicles. Besides the analysis of free flow and synchronized traffic the data sets especially provide information about wide jams that persist for a long time. The data have been collected at a location far away from ramps and in the absence of speed limits, which allows a comparison with idealized traffic simulations. We also resolve some open questions concerning the time-headway distribution.

Random walk theory of jamming in a cellular automaton model for traffic flow

The jamming behavior of a single lane traffic model based on a cellular automaton approach is studied. Our investigations concentrate on the so-called VDR model which is a simple generalization of the well-known Nagel–Schreckenberg model. In the VDR model one finds a separation between a free flow phase and jammed vehicles. This phase separation allows to use random walk like arguments to predict the resolving probabilities and lifetimes of jam clusters or disturbances. These predictions are in good agreement with the results of computer simulations and even become exact for a special case of the model. Our findings allow a deeper insight into the dynamics of wide jams occuring in the model.

Experimental Features of Self-Organization in Traffic Flow

Features of the ``stop-and-go'' phenomenon are found. First, the local phase transition ``free flow $\ensuremath{\rightarrow}$ synchronized flow'' is realized. Then the ``pinch effect'' in synchronized flow occurs. In the pinch region a complex sequence of narrow jams is self-formed. The following transformation of the narrow jams into wide jams determines a scale in distances between stop-and-go patterns.