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.

Generalised processor sharing networks fed by heavy-tailed traffic flows

Abstract: We consider networks where traffic is served according to the generalised processor sharing (GPS) principle. GPS-based scheduling algorithms are considered important for providing differentiated quality of service in integrated-services networks. We are interested in the workload of a particular flow i at the bottleneck node on its path. Flow i is assumed to have long-tailed traffic characteristics. We distinguish between two traffic scenarios, (i) flow i generates instantaneous traffic bursts and (ii) flow i generates traffic according to an on/off process. In addition, we consider two configurations of feedforward networks. First we focus on the situation where other flows join the path of flow i. Then we extend the model by adding flows which may branch off at any node, with cross traffic as a special case. We prove that under certain conditions the tail behaviour of the workload distribution of flow i is equivalent to that in a two-node tandem network where flow i is served in isolation at constant rates. These rates only depend on the traffic characteristics of the other flows through their average rates. This means that the results do not rely on any specific assumptions regarding the traffic processes of the other flows. In particular, flow i is not affected by excessive activity of flows with 'heavier-tailed' traffic characteristics. This confirms that GPS has the potential to protect individual flows against extreme behaviour of other flows, while obtaining substantial multiplexing gains.

Design of an intelligence traffic light controller (ITLC) with VHDL

Abstract: The intelligence traffic light controller is considered for the busy time on the road when people are going to work and the traffic light timing control Traffic congestion increases because the current traffic light controller only allocates a fixed time control ITLC can reduce the waste time to drivers on the road In this paper the traffic lights of main roads are controlled with fixed time while narrow roads are controlled autonomously by sensors ITLC's efficiency is increased when there are fewer vehicles on the narrow road The experimental result shows that the efficiency of the ITLC can achieve a maximum 36%

Study on traffic flow affected by the road turning

Abstract: Base on the NaSch model, an improved single-lane cellular automaton traffic flow model for especial road is proposed via considering effects of curvature radii, arc length and friction factor on the vehicle movement. By numerical simulation for the traffic flow with different curvature radii, arc length and friction factor, it is found that our improved model can reflect accurately the influence of special sections of a road on the running vehicles, meanwhile visualize the complex nonlinear phenomenon traffic waves of alternate running and stopping as in actual traffics. The reflecting phenomenon in actual traffics indicates that traffic accidents and congestion can be avoided by increase the curvature radii, friction factor of road turning, the capacity of road can be enhanced also.

Effects of Bottlenecks on Vehicle Traffic

Abstract: Traffic congestion is usually observed at the upper stream of bottlenecks such as tunnels. Congestion appears as stop-and-go waves and high-density uniform flow. We perform simulations of traffic flow with a bottleneck using the coupled map optimal velocity model. The bottleneck is expressed as a road segment with speed reduction. The speed reduction in the bottleneck controls the emergence of stop-and-go waves. A phenomenological theory of bottleneck effects is constructed.

A Traffic Signal Optimization Strategy Considering Both Vehicular and Pedestrian Flows

Abstract: Current signal control strategies tend to ignore the pedestrian delays that may be imposed by reducing traffic delays. Such an objective is reasonable for motorways and rural roads where vehicular traffic is dominant over pedestrian traffic. However, it is not the case in metropolitan cities with large volume of pedestrian demands. This paper developed a traffic signal optimization strategy that considers both vehicular and pedestrian flows. The objective of the proposed model is to minimize the weighted vehicular and pedestrian delays. The deterministic queuing model is used to calculate vehicular traffic delay and pedestrian delay on sidewalk. Pedestrian delay on crosswalk is calculated based on an empirical pedestrian speed model, which considers interactions of pedestrian platoons and their impacts on average walking speed. The proposed model is first implemented at a Japanese intersection. MATLAB is utilized to solve the optimization problem and to output a set of MOEs. The results show that the proposed model improved average person delay (APRD) by 10% without changing the existing cycle length. Moreover, the model can optimize the cycle length and further improve APRD by as much as 44%. In order to demonstrate the applicability of the proposed model for general cases, this paper also conducted sensitivity analysis. According to the results, the proposed model is most significant and necessary for two circumstances: (1) metropolitan areas with high pedestrian demands and (2) major urban arterials with high pedestrian demands crossing the major streets.