Traffic wave

About: Traffic wave is a research topic. Over the lifetime, 2106 publications have been published within this topic receiving 62117 citations. The topic is also known as: phantom traffic jam & ghost jams.

Nonlinear-map model for split effect on vehicular traffic through periodic signals

Abstract: We study the effects of both split and cycle time on dynamical behavior of vehicles moving through a sequence of traffic lights on a highway, where the traffic lights turn on and off periodically. The dynamical model of vehicular traffic controlled by signals is expressed in terms of a nonlinear map. The vehicle exhibits complex behavior with varying split and cycle time. The tour time between signals shows a self-similar behavior. When split sp is lower than 0.5, vehicular traffic shows a similar behavior as that of sp=0.5, while vehicular traffic of sp>0.5 is definitely different from that of s p ⩽ 0.5 . The algebraic expression among the tour time, cycle time, and split is derived.

On Traffic Equilibrium, Congestion Tolls, and the Allocation of Transportation Capacity in a Congested Urban Area

Abstract: In a continuous transportation model with a scalar velocity field, dependent on the ratio of traffic to transportation capacity, and with trips generated by a gravity or entropy hypothesis, the equilibrium traffic distribution is derived along with the optimal capacity distribution. Possible improvements by introducing congestion tolls are discussed. It is seen that capacity should be distributed in proportion to traffic, so that velocity of transfer is constant, trips go along straight lines, and traffic is minimized. This implies that capacity is concentrated to the central parts. Congestion tolls are superfluous when capacity is optimally allocated.

Traffic signal synchronization in the saturated high-density grid road network

Abstract: Most existing traffic signal synchronization strategies do not perform well in the saturated high-density grid road network (HGRN). Traffic congestion often occurs in the saturated HGRN, and the mobility of the network is difficult to restore. In order to alleviate traffic congestion and to improve traffic efficiency in the network, the study proposes a regional traffic signal synchronization strategy, named the long green and long red (LGLR) traffic signal synchronization strategy. The essence of the strategy is to control the formation and dissipation of queues and to maximize the efficiency of traffic flows at signalized intersections in the saturated HGRN. With this strategy, the same signal control timing plan is used at all signalized intersections in the HGRN, and the straight phase of the control timing plan has a long green time and a long red time. Therefore, continuous traffic flows can be maintained when vehicles travel, and traffic congestion can be alleviated when vehicles stop. Using the strategy, the LGLR traffic signal synchronization model is developed, with the objective of minimizing the number of stops. Finally, the simulation is executed to analyze the performance of the model by comparing it to other models, and the superiority of the LGLR model is evident in terms of delay, number of stops, queue length, and overall performance in the saturated HGRN.

Controlling the States of Traffic Flow at the Intersections

Abstract: In city network, the state of the traffic flow which is in front of each intersection is random and disorder. It usually leads to some traffic problems. In this paper, we propose a new technique to control such dynamical state of the traffic flow on a main road. A type of the control signal has been designated at a given site (signal point) in front of each intersection. Under the effect of the control signal, the velocities of the vehicles which pass the signal point will be changed. Our method is tested for the "unified" CA traffic model which is the marriage of the NaSch model and the BML model. The simulation results demonstrate that using this control strategy, when the traffic light is green, the disorder state of the traffic flow which is in front of each intersection can be suppressed, and the periodic state of the traffic flow will occur.