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.

Fukui–Ishibashi Traffic Flow Models with Anticipation of Movement of the Car Ahead

Abstract: We propose and study new vehicular traffic flow models, incorporating the anticipation of the change in the car spacings ahead in the determination of the speed of the cars in each time step. Our models are based upon the Fukui and Ishibashi (FI) traffic flow model in which cars are allowed to move a maximum of M sites in each time step if spacing permits, together with a probabilistic delay for the cars moving at the maximum speed. By taking into account the anticipation in the change of car spacing due to movement of the car ahead, the present models give an enhanced traffic flux as compared to the FI model. The present models also give a fundamental diagram consisting of three phases – a feature consistent with traffic flow observations.

Exploring the Effect of Variability of Urban System Characteristics in the Network Capacity

Abstract: Mobility and transportation are two of the leading indicators of economic growth of a society. As cities around the world grow rapidly and more people and modes compete for limited urban space to travel, there is an increasing need to understand how this space is used for transportation and how it can be managed to improve accessibility for everyone. In a recent paper Daganzo and Geroliminis explored the connection between network structure and a network’s Macroscopic Fundamental Diagram (MFD) for urban neighborhoods with cars controlled by traffic signals and derived an analytical theory for the MFD using Variational Theory. Information needed to estimate this network MFD’s are average network (total length of roads in lane-km, number of lanes, length of links), control (signal offsets, green phase and cycle time) and traffic (free flow speed, congested wave speed, jam density, capacity) characteristics. However in previous studies, Variational Theory has been applied only in cities with deterministic values of the above variables for the whole network and by ignoring the effect of turns. In the study the authors are aiming to generate an MFD for streets with variable link lengths and signal characteristics and understand the effect of variability for different cities and signal structures. Furthermore, this variability gives the opportunity to mimic the effect of turning movements and heterogeneity in driver’s behavior. This will be a key issue in planning the signal regimes such a way that maximizes the network capacity and/or the density range of the capacity.

Integrated Framework of Vehicle Dynamics, Instabilities, Energy Models, and Sparse Flow Smoothing Controllers

Abstract: This work presents an integrated framework of: vehicle dynamics models, with a particular attention to instabilities and traffic waves; vehicle energy models, with particular attention to accurate energy values for strongly unsteady driving profiles; and sparse Lagrangian controls via automated vehicles, with a focus on controls that can be executed via existing technology such as adaptive cruise control systems. This framework serves as a key building block in developing control strategies for human-in-the-loop traffic flow smoothing on real highways. In this contribution, we outline the fundamental merits of integrating vehicle dynamics and energy modeling into a single framework, and we demonstrate the energy impact of sparse flow smoothing controllers via simulation results.

The development and dispersal of area-wide traffic jams /

Abstract: The development and dispersal of area-wide traffic jams is a matter of considerable social concern. Work at Middlesex University has enabled the construction of a simulation model with greater geographical scope than most conventional congestion simulation models. This paper proposes a simulation model which concentrates on a holistic view of traffic jam formation in a setting of isotropic flow. In the model, traffic incidents can effectively be introduced anywhere in the network. The growth of traffic jams can be observed using a graphical display and options are included to disperse and control the formation of traffic queues. Simulation results have shown that the uncontrolled growth of the traffic jam is both rapid and potentially irreversible. Attempts to disperse the traffic jam appear to be hampered by 'gridlock' phenomena. The paper describes a number of strategies which could be exploited to achieve a controlled dispersion of traffic jams.

Managing traffic congestion in combined freeway and traffic signal networks

Abstract: An overview is provided of the modelling approach of Integration-1 (which deals specifically with integrated networks), and discusses and illustrates its features for dealing with traffic congestion problems using a typical model simulation run. Integration-1 consists of a discrete simulation that traces the path of each vehicle throughout the network. The links that a vehicle utilizes are selected in accordance with its estimate of the best route, and, along its path, each vehicle's route is further adjusted in view of any changes in the prevailing traffic congestion and traffic controls. Not only does this model allow a more detailed examination of certain strategies in isolation, such as critical intersection control, realtime control, or improved driver information systems, but it also allows the complex interactions to be studied simultaneously. Integration-1 is a research tool and requires a significant amount of further development.