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The existence of different types of Commercial Vehicles (CVs) in the shared roadway affects traffic flow characteristics differently from other vehicles. Owing to the uncertain placement and movement of these CVs in both longitudinal and lateral directions, the opportunities for lane changing and overtaking by other vehicles with lower maneuverability decrease, resulting in the formation of platoons. The study's primary aim is to assess the effect of mixed traffic platoons formed by three different classes of CVs on highway traffic speed, flow, and density under two different traffic regimes (regimes A and B). In this study, regime A represents the non-platooning condition, and regime B represents the platooning condition. Bi-directional traffic data was collected from the highway sections in India using an Infra-Red sensor-based device. The critical leading time headway is determined for the different CVs (platoon leaders) based on the mean absolute relative speed of platoons. The speed-flow-density plots are established using the macroscopic fundamental diagrams for the highway sections under regimes A and B to quantify the platooning impacts of CVs on the traffic characteristics. The study findings reveal that the speed at capacity, density at capacity, and traffic capacity decreased significantly due to CVs' influence on the general traffic mix during the mixed traffic platooning conditions. However, this effect was found to be relatively higher during the Heavy Commercial Vehicle operation as a platoon leader compared to Medium Commercial Vehicle and Light Commercial Vehicle as a platoon leader. [ABSTRACT FROM AUTHOR]

Abstract: Similarly to the treatment of diluted gases, kinetic methods are formulated for the study of unidirectional freeway traffic. From these it is possible to construct fluid-dynamic equations which in comparison with heuristic fluid-dynamic models have the advantage of just some adjustable parameters although they have some other restrictions. In this work the comparison between two macroscopic models which are based on a kinetic traffic equation is shown. On the other hand, there will be presented some advances to attempt to generalize some restrictions of the kinetic formulation in order to study the synchronization phenomena, which is a very interesting transitory phase between free flow and traffic jams. [ABSTRACT FROM AUTHOR]

Abstract: The balanced vehicular traffic model is a macroscopic model for vehicular traffic flow. We use this model to study the traffic dynamics at highway bottlenecks either caused by the restriction of the number of lanes or by on-ramps or off-ramps. The coupling conditions for the Riemann problem of the system are applied in order to treat the interface between different road sections consistently. Our numerical simulations show the appearance of synchronized flow at highway bottlenecks. [Copyright &y& Elsevier]

Abstract: The kinetic theory for traffic flow equations can be approached using the Grad’s method. This method, which is derived from the kinetic gas theory, was developed for the Paveri-Fontana equation when a special desired velocity model is assumed. A closure relation for the set of macroscopic equations is found when the density, the average velocity and the velocity variance are the relevant variables chosen to describe the system. Simulation results are also shown and a qualitative comparison with other models in the literature is presented. [Copyright &y& Elsevier]

We present a new fluid-dynamical model of traffic flow. This model generalizes the model of Aw and Rascle [SIAM J. Appl. Math., 60 (2000), pp. 916-938] and Greenberg [SIAM J. Appl. Math., 62 (2001), pp. 729-745] by prescribing a more general source term to the velocity equation. This source term can be physically motivated by experimental data, when taking into account relaxation and reaction time. In particular, the new model has a (linearly) unstable regime as observed in traffic dynamics. We develop a numerical code that solves the corresponding system of balance laws. Applying our code to a wide variety of initial data, we find the observed inverse-λ shape of the fundamental diagram of traffic flow. [ABSTRACT FROM AUTHOR]

The modeling of traffic flow is a key tool to simulate and predict the behavior of traffic systems. Macroscopic traffic simulation models are based on advection dominated coupled non-linear partial differential equations. The solution of such advection dominated equations with the method of finite elements is leading to the development of stabilization techniques. The choice of suitable stabilization parameters is often application-dependent. A stabilized finite element procedure on the basis of a Galerkin/least-square approximation is presented for systems of transient advection-dominated equations. A general rule for computing suitable element stabilization parameters is outlined which uses the spectral radius of the differential operators and the specific element expansion. The application of this approximation to a macroscopic traffic model shows the applicability of this approach. Simulation results of typical phenomena of jam formation in freeway traffic are presented. [ABSTRACT FROM AUTHOR]

Forecasting future driving conditions such as acceleration, velocity, and driver behaviors can greatly contribute to safety, mobility, and sustainability issues in the development of new energy vehicles (NEVs). In this brief, a review of existing velocity prediction techniques is studied from the perspective of traffic flow and vehicle lateral dynamics for the first time. A classification framework for velocity prediction in NEVs is presented where various state-of-the-art approaches are put forward. Firstly, we investigate road traffic flow models, under which a driving-scenario-based assessment is introduced. Secondly, vehicle speed prediction methods for NEVs are given where an extensive discussion on traffic flow model classification based on traffic big data and artificial intelligence is carried out. Thirdly, the influence of vehicle lateral dynamics and correlation control methods for vehicle speed prediction are reviewed. Suitable applications of each approach are presented according to their characteristics. Future trends and questions in the development of NEVs from different angles are discussed. Finally, different from existing review papers, we introduce application examples, demonstrating the potential applications of the highlighted concepts in next-generation intelligent transportation systems. To sum up, this review not only gives the first comprehensive analysis and review of road traffic network, vehicle handling stability, and velocity prediction strategies, but also indicates possible applications of each method to prospective designers, where researchers and scholars can better choose the right method on velocity prediction in the development of NEVs. [ABSTRACT FROM AUTHOR]

• The multi-class S model describes the heterogeneous flow of vehicles. • The performance of multi-class S model is compared with the single-class S model using microsimulation as a reference. • The computation time of the macroscopic models does not depend on the number of vehicles. In this paper a new multi-class urban traffic model is proposed based on the features of a single-class urban traffic model and the characteristics of a multi-class freeway traffic model. The heterogeneous traffic flow is represented using the concept of Passenger Car Equivalent (PCE) for congestion and free-flow regimes separately. The proposed multi-class urban traffic model is intended for model-based control applications. The single-class model and the proposed multi-class traffic model are compared with microscopic simulation data obtained using the SUMO (Simulation of Urban MObility) open-source simulator. The two models are calibrated through optimal parameter estimation and their performance is evaluated and compared by taking into account the error index between the models and the simulation data. Simulation results show that the multi-class model gives a significantly better fit. [ABSTRACT FROM AUTHOR]

Traffic flow will harmonize to forward conditions. The time and distance required for harmonization can have a significant effect on the traffic density behavior. The flow can evolve into clusters of vehicles or become uniform depending on parameters such as safe time headway and safe distance headway. In this paper, a new model is presented to provide a realistic characterization of traffic behavior during the harmonization period. Results are presented for a discontinuous density distribution on a circular road which shows that this model produces more realistic traffic behavior than other models in the literature. [ABSTRACT FROM AUTHOR]