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.

Smoothing Traffic Flow via Control of Autonomous Vehicles

Abstract: The emergence of autonomous vehicles is expected to revolutionize road transportation in the near future. Although large-scale numerical simulations and small-scale experiments have shown promising results, a comprehensive theoretical understanding to smooth traffic flow via autonomous vehicles is lacking. In this paper, from a control-theoretic perspective, we establish analytical results on the controllability, stabilizability, and reachability of a mixed traffic system consisting of human-driven vehicles and autonomous vehicles in a ring road. We show that the mixed traffic system is not completely controllable, but is stabilizable, indicating that autonomous vehicles can not only suppress unstable traffic waves but also guide the traffic flow to a higher speed. Accordingly, we establish the maximum traffic speed achievable via controlling autonomous vehicles. Numerical results show that the traffic speed can be increased by over 6% when there are only 5% autonomous vehicles. We also design an optimal control strategy for autonomous vehicles to actively dampen undesirable perturbations. These theoretical findings validate the high potential of autonomous vehicles to smooth traffic flow.

Car Travel Time Estimation near a Bus Stop with Non-motorized Vehicles

Abstract: Real time system for vehicle travel time and traffic flow is an essential part of Intelligent Transportation Systems. In many Chinese cities, the interactions among buses, bicycles and cars bring difficulty to travel time prediction and traffic safety management. The aim of this paper is to develop a new model to estimate car travel time near bus stops in developing countries by data mining techniques and survival analysis methods. The travel time data under mixed traffic conditions are collected by video camera. Four influential factors including car volume, nonmotorized volume, bus departure volume and free ratio of bus stop are chosen by using data mining techniques. A proportional hazard-based duration model is proposed to analyze the factors related to car travel time. The results indicate that mixed traffic flow impacts the car travel time significantly. In addition, various factors can modify the travel time distribution in different degrees and the model can be used to estimate the travel time und...

Artery vehicle track reconstruction method based on data fusion of electronic police and fixed point detector

Abstract: Provided is an artery vehicle track reconstruction method based on data fusion of electronic polices and fixed point detectors. The method includes the following steps: inputting a certain number of vehicles into a control system at specified time, specified roads or crossings; introducing constraints on the basis of an actual traffic running mode and a traffic wave associated theory, and screening a small number of reasonable tracks from possible tracks; taking actual traffic running conditions as reference, screening out an optimal track which is closest to reality from a small number of reasonable tracks by taking relevant parameters reflecting the actual traffic running conditions as standards, and then completing track reconstruction. The constraints include queuing overflow identification in fixed point detector; space-time area free flow speed acquisition; segmentation of upstream phase sequences and set timing periods; upstream input flow acquisition; and vehicle diversion behavior partition based on electronic police data. Reconstructed track adjustment is carried out on the basis of traffic parameters reflecting the actual traffic running conditions and then a final reconstructed track that better accords with reality is obtained, so the track reconstruction accuracy is improved.