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The use of modeling and simulation aids in deriving many decisions related to transportation planning and traffic operations. Representing the real systems via simulation allows exploring system behavior in an articulated way, which is often impossible in the real world. In this paper, a simulation-based framework is presented to evaluate the impact of congestion charging on daily activity plans of the individuals. Personal decision to accept the congestion charges is evaluated by comparing the value of time with congestion charge. Value of time varies throughout the day depending upon the time pressure at any moment exerted by preceding and succeeding activities. Time pressure during an activity increases if available time for that activity is insufficient to attain the perceived utility. Daily activities in the schedules are modeled using bell-shaped marginal utility that results in sigmoid utility. A model is presented which derives the activity-specific parameters of the marginal utility function for the specific individual. To examine value of time of each person, the congestion charging is applied where personal willingness-to-pay is determined by comparing the ratios of cost to utility for original and adapted schedules. A large-scaled microsimulation of the modeled framework is used to simulate the whole population, which is created by FEATHERS, an operational activity-based model for Flanders, Belgium. The results of the simulation show that the number of individuals who avoid the congestion charges by adapting their schedules is almost three times the number of those who agree to pay it. The proposed framework can be useful to evaluate the tradeoff between value of time and costs where flexibility in selection of time defines the variability in cost. [ABSTRACT FROM AUTHOR]

This paper proposes test scenarios for evaluation of yaw stability for medium commercial vehicles. Maneuvering, speed, longitudinal tire force, tire-road friction coefficient, road slope, and load condition are considerable factors that have effect on the medium commercial vehicle yaw stability. After conducting an analysis on these six factors, effective test scenarios were developed. A sine with dwell test is well known as a test scenario for evaluation of performance of electronic stability control (ESC) on passenger vehicles and heavy commercial vehicles. The SWD test was modified considering medium commercial vehicle dynamics, and the ramp steer maneuver with maximum acceleration test was proposed. Simulation validation has been conducted using field test data. From simulation study, it was shown that the ESC system for medium commercial vehicle is effectively evaluated by the proposed test scenarios. [ABSTRACT FROM AUTHOR]

The paper describes a simulation model of a moving automobile and a pedestrian run out to the traffic area with the accident probability calculation. A set of curves showing the accident probability vs. automobile speed for various pedestrian's walking paces is obtained. A method is offered, which allows to decrease accident probability by using a specialized controller analyzing the changing road situation. A set of curves describing the accident probability vs. automobile speed while using the controller is also obtained. [ABSTRACT FROM AUTHOR]

We study reconfigurations of wavelength-routed Wavelength Division Multiplexing (WDM) networks in response to lightpath demand changes, with the objective of servicing more lightpath demands without additional network resources from a long-term network operation point of view. For the reconfiguration problem under study, we assume WDM network operators are provided with lightpath demands in batches. With limited network resources, our problem has two unique challenges: balancing network resource allocations between current and future lightpath demands, and modeling future lightpath demands. The first challenge implies making tradeoffs between accepting as many current immediate lightpath demands as possible and reserving a certain amount of network resources for near future predicted lightpath demands. The second challenge implies modeling future predicted lightpath demands, which are not exactly known or certain as the current lightpath demands. Our proposed model allows a natural separation between the operation of the optical layer and the user traffic layer (predominantly the IP-layer), while supporting their interactions, for which we propose a new formulation for per-link congestion control, associated with a mathematical solution procedure. Our simulation results reveal that by properly controlling resource allocations in the current session using our proposed mechanism, rejections in future sessions are greatly reduced. [ABSTRACT FROM AUTHOR]

In this paper, an optimization method is presented for instructions to evacuate by car the population of a region threatened by a hazard. By giving the optimized instructions to the evacuees, traffic conditions and, therefore, the evacuation efficiency are optimized. The instructions, containing a departure time, a safe destination, and a route, are created using an optimization method consisting of two phases: the generation of the search space and the algorithm AES evacuation, a version of ant colony optimization. The main contributions of the proposed optimization method are the unique approach to generate the search space in which network degeneration is taken into consideration, the possibility to optimize instructions under the assumption of both full and partial compliance of the evacuees with the instructions, and the flexibility in the sense that the user of the method can define his or her own objective function and choose a suitable traffic simulation model. The paper contains a comprehensive case study. The case study shows that the effectiveness of the optimized instructions is more than doubled when compared with the effectiveness of instructions set up by straightforward rules (like evacuating to the nearest destination using the shortest route). Further, the case study shows that the number of arrivals under optimized, but possibly sub-optimal instructions is equal to at least 90% of the theoretical upper bound on this number of arrivals. [ABSTRACT FROM AUTHOR]

Multi-agent systems allow the simulation of complex phenomena that cannot be easily described analytically. As an efficient tool, the agent-oriented traffic models have emerged to investigate vehicular traffic behaviors. In this article, a new agent-based traffic simulation model is proposed for solving the traffic simulation problems. A vehicle with the driver is represented as a composite autonomous agent in this model. Different from the classical car-following principles, vehicle-agent moving approaches are proposed instead of particle-hopping techniques. This model defines reasonable acceleration and deceleration rates at any certain condition. In this simulation, this can offer a natural, even cognitive way to follow the leader and switch lane. The simulation results have verified that this model has achieved more realistic results without loss of accuracy than those obtained from the cellular automata traffic models. This model can provide better simulation performance than the traditional vehicle-following models which are used to investigate the nonequilibrium traffic flow. A comparison of the real flow with the simulated freeway flow and lane capacity highlights the validness of this model. [ABSTRACT FROM AUTHOR]

There has been a debate in the transportation research community over the validity of a class of traffic flow models. These models have the peculiar property that one of its characteristic speeds is faster than that of vehicular traffic. This note attempts to provide an overview of the diverging views on how to interpret this property, and specific comments on the interpretation of Helbing and Johansson [ On the controversy around Daganzo’s requiem for and Aw-Rascle’s resurrection of second-order traffic flow models, Eur. Phys. J. B (2009), DOI: 10.1140/epjb/e2009-00182-7]. We showed that having faster-than-traffic characteristics does produce counterintuitive predictions, and they cannot be explained away by a linear stability analysis. As such, the existence of such characteristics must be justified by the physics of traffic, and verified through empirical observations. [ABSTRACT FROM AUTHOR]

This contribution compares several different approaches allowing one to derive macroscopic traffic equation directly from microscopic car-following models. While it is shown that some conventional approaches lead to theoretical problems, it is proposed to use an approach reminding of smoothed particle hydrodynamics to avoid gradient expansions. The derivation circumvents approximations and, therefore, demonstrates the large range of validity of macroscopic traffic equations, without the need of averaging over many vehicles. It also gives an expression for the “traffic pressure”, which generalizes previously used formulas. Furthermore, the method avoids theoretical inconsistencies of macroscopic traffic models, which have been criticized in the past by Daganzo and others. [ABSTRACT FROM AUTHOR]

Traffic is highly influenced by network structure and human behaviour. Small changes in the human behaviour can lead to huge changes in the load of a traffic network. Current transportation models do not, and most of them cannot, research such random behaviour but always calculate a steady state. In our multi-agent transport simulation, we frequently observe seemingly random “network breakdowns”, huge traffic jams that spread over a big part of the network, making a normal traffic flow impossible. This paper describes the investigations that were performed on the results of our large-scale multi-agent transport simulations in an attempt to contribute to the better understanding of the dynamic processes in such simulations and, hopefully, better understanding and modelling of the real-world. [ABSTRACT FROM AUTHOR]

An extended car following model is proposed by incorporating intelligent transportation system and the backward looking effect under certain condition in traffic flow. The neutral stability condition of this model is obtained by using the linear stability theory. The results show that anticipating the behavior of vehicles preceding and following one vehicle could lead to appreciable stabilization of traffic system. From the simulation of space-time evolution of the vehicle headways, it is shown that the traffic jam could be suppressed efficiently via taking into account the information about the motion of two preceding vehicles and one following vehicle, and the analytical result is consistent with the simulation one. [ABSTRACT FROM AUTHOR]

Mathematical models of control of traffic in the Internet are considered. Analysis is made on approaches, models, interpretation methods, and questions arising in problems of congestion control on the basis of the interaction of TCP/AQM protocols. [ABSTRACT FROM AUTHOR]

Examines the effects of open boundaries on the dynamical behavior of optimal velocity traffic flow model with a delay time allowing the car to reach its optimal velocity using numerical simulations. Mathematical description of the traffic flow model; Analysis of the critical value of traffic flows; Examination of the space-time evolution for various values of extracting rate probability.

Cellular automaton traffic models can include various factors in traffic systems and the corresponding computational simulations are rather simple and effective. The Biham-Middleton-Levine model (BML model) facilitates the simulation of two-dimentional traffic flow problems via the cellular automaton models. In this paper, the BML model is improved by removing its limitation of synchronized change of traffic lights. In the new model, the traffic light at each crossing could arbitrarily change its starting time and tempo of variation, and hence the model could more realistically describe the influence of traffic lights on the performance of traffic systems. Some new effects appearing in the new model are also elucidated. [ABSTRACT FROM AUTHOR]