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The traditional vehicle mobility is restricted to the driver habits and the line-of-sight. The new-emerging connected vehicles enable information exchange with each other at vicinity, which will undoubtedly bring a greatly positive effect on the vehicle mobility pattern. In this paper, we propose to modeling and analyzing the vehicle mobility patterns respectively driven by traditional drivers and connected drivers. We perform the extensive simulations to explore the statistical differences between two mobility patterns and the underlying reasons through comparing to the real vehicle trace datasets. The results show that they behave quite diversely at the concerned aspects, e.g. degree distribution, clustering coefficient, topological shortest path, topological coefficient, and vehicle density, and also we find that the connected vehicles are well distributed and contribute a relieved traffic congestion situation. [ABSTRACT FROM AUTHOR]

In order to reveal the influence of driver’s individual behavior on traffic flow more accurately, a new car-following model is proposed with consideration of multiple drives’ desired velocities. The stability criterion of the new model is derived through linear stability theory and the results show that the current driver’s desired velocity can stabilize traffic flow but the preceding driver’s desired velocity can damage traffic stability. Through nonlinear analysis, the traffic jamming transition characteristics near the critical point can be described by the kink–antikink soliton of the mKdV equation. Numerical simulation confirms the analytical results, which shows that the multiple drivers’ desired velocities play an important role in traffic evolution. [ABSTRACT FROM AUTHOR]

There is an incompatibility between how transport engineers think drivers behave in roadworks and how they actually behave. As a result of this incompatibility we are losing approximately a lane's worth of capacity in addition to those closed by the roadworks themselves. The problem would have little significance were it not for the fact a lane of motorway costs approx. £30 m per mile to construct and £43 k a year to maintain, and that many more roadworks are planned as infrastructure constructed 40 or 50 years previously reaches a critical stage in its lifecycle. Given current traffic volumes, and the sensitivity of road networks to congestion, the effects of roadworks need to be accurately assessed. To do this requires a new ergonomic approach. A large-scale observational study of real traffic conditions was used to identify the issues and impacts, which were then mapped to the ergonomic knowledge-base on driver behaviour, and combined to developed practical guidelines to help in modelling future roadworks scenarios with greater behavioural accuracy. Also stemming from the work are novel directions for the future ergonomic design of roadworks themselves. [ABSTRACT FROM AUTHOR]

Aims: The aim of the study was to make a theoretical contribution by investigating social cognitive factors and personality traits related to risky driver behaviour in a Turkish sample. The study tested three theoretical models by Structural Equation Modelling: (1) a model using risk perception and attitudes towards traffic safety to predict driver behaviour, (2) a model which used normlessness and sensation-seeking traits to predict such behaviour and (3) a model which used both the social cognitive factors and personality traits to predict driver behaviour.Methods: A questionnaire survey with validated measurement instruments was conducted in a sample of Turkish drivers (n = 213). The response rate was 61%.Results: A combined social cognitive and personality trait model had tolerable fit and explained 24% of the variance in driver behaviour. The relations between personality traits and risk perception with driver behaviour were mediated through attitudes towards traffic safety. Risk-taking personality traits had relatively strong relations to unsafe driver behaviour, whereas risk perception had a relatively weak relation to such behaviour.Conclusions: A combined social cognitive and trait approach may be efficient in human factor campaigns aimed to reduce risky driver behaviour in Turkey. Personality traits may be important for driver behaviour because they influence the attitudinal determinants of such behaviour. Increased police enforcement of road traffic regulations may reduce risky driving among individuals with normlessness and sensation-seeking traits. Personality traits may also guide efforts aimed at early identification of risky drivers and campaigns could be tailored to specific personality characteristics. [ABSTRACT FROM PUBLISHER]

Abstract: This paper studies traffic hysteresis arising in traffic oscillations from a behavioral perspective. It is found that the occurrence and type of traffic hysteresis is closely correlated with driver behavior when experiencing traffic oscillations and with the time driver reaction begins relative to the starting deceleration wave. Statistical results suggest that driver behavior is different depending on its position along the oscillation. This suggests that different car-following models should be used inside the different stages of an oscillation in order to replicate realistic congestion features. [Copyright &y& Elsevier]

This paper investigated variations in accepted gaps and lane change duration on arterial under recurrent and non-recurrent congestion. Descriptive statistics and best-fit distributions were obtained for the two parameters for both traffic conditions. Hypothesis testing using Mann-Whitney U-Test showed that the means of accepted gaps and lane change durations were statistically different between the two types of traffic conditions. The study found that during non-recurrent congestion, drivers on an average accepted smaller gaps but took longer lane change durations. Based on the fact that the data were collected for the same flow-rate (70-90 vehicles/minute) in both traffic conditions and based on the literature, the reason for the above findings could be that, drivers get more frustrated during non-recurring congestion that they accept smaller gaps. Drivers visiting the study location for game day (non-recurrent) exhibit different driver behavioral characteristics when compared to regular commuters (recurrent) which could have also contributed to the statistical differences in the lane changing characteristics of two types of congestion. These findings have direct implications on the lane changing parameters used in microscopic traffic simulation and also help transportation planners and managers to understand driver behavior during recurrent and non-recurrent congestion and better manage the facilities. [ABSTRACT FROM AUTHOR]

Abstract: A continuum model that describes a disordered, heterogeneous traffic stream is presented. Such systems are widely prevalent in developing countries where classical traffic models cannot be readily applied. The characteristics of such systems are unique since drivers of smaller vehicles exploit their maneuverability to move ahead through lateral gaps at lower speeds. At higher speeds, larger vehicles press their advantage of greater motive power. The traffic stream at the microscopic level is disordered and defines a porous medium. Each vehicle is considered to move through a series of pores defined by other vehicles. A speed-density relationship that explicitly considers the pore space distribution is presented. This captures the considerable dynamics between vehicle classes that are overlooked when all classes are converted to a reference class (usually Passenger Car Equivalents) as is traditionally done. Using a finite difference approximation scheme, traffic evolution for a two-class traffic stream is shown. [Copyright &y& Elsevier]

Previous works have pointed out that one of the reasons for the formation of traffic congestion is instability in traffic flow. In this study, we investigate theoretically how the characteristics of individual drivers influence the instability of traffic flow. The discussions are based on the optimal velocity model, which has three parameters related to individual driver characteristics. We specify the mappings between the model parameters and driver characteristics in this study. With linear stability analysis, we obtain a condition for when instability occurs and a constraint about how the model parameters influence the unstable traffic flow. Meanwhile, we also determine how the region of unstable flow densities depends on these parameters. Additionally, the Langevin approach theoretically validates that under the constraint, the macroscopic characteristics of the unstable traffic flow becomes a mixture of free flows and congestions. All of these results imply that both overly aggressive and overly conservative drivers are capable of triggering traffic congestion. [ABSTRACT FROM AUTHOR]

This paper explores potential driver behavior changes due to the interactions with advanced vehicle technologies emerging on the market. These technologies, called Advanced Driver Assistance Systems (ADAS) can take control over specific functions of the vehicle, and provide warnings to assist drivers in a variety of driving tasks. These technologies were designed mainly to improve roadway safety and provide comfort to drivers. There is evidence that these systems may change the way drivers behave on the road, resulting in traffic operational improvements and congestion mitigation, but a limited amount of research has been conducted to assess these potential impacts. This study evaluated performance measures of a vehicle equipped with two types of ADAS in a driving simulator (STISIM Drive) environment. Two systems, which are more likely to affect traffic operations, were evaluated: Adaptive Cruise Control (ACC) and Lane Change Assist (LCA). A specific route was created in the driving simulator, which consisted of an arterial section followed by a freeway. This route was driven twice by drivers: first without the systems and secondly using the two ADAS. There were a total of 25 participants with varying characteristics and backgrounds. Performance measures such as speed, lane change maneuvers, and headway with the front vehicle were collected. The analysis compared driver performance for different driver groups as well as for the entire sample. Peformance without the systems was compared to that obtained while the systems were used. Results showed changes in driving behavior due to the systems and specific driver's characteristics that are more likely to be affected by these technologies. [ABSTRACT FROM AUTHOR]

Abstract: This paper first presents a method to estimate Newell’s car-following model parameters in congestion at a microscopic scale. I-80 NGSim data analysis shows that at this scale driving behaviors vary from one vehicle to the another. Then, relations between stochastic Newell’s model with heterogeneous drivers and its associated macroscopic pattern are established. This proves that the mean jam spacing is the arithmetic mean of individual jam spacings whereas the mean wave speed is the harmonic mean of individual wave speeds. These new insights are valuable for (i) calibrating a macroscopic model from individual observations and (ii) establishing the equivalence between the stochastic and the well-calibrated deterministic versions of Newell’s model for a sufficiently large number of vehicles. [Copyright &y& Elsevier]

Despite the potential effectiveness of the dynamic late merge (DLM) control, most existing DLM systems, based on static thresholds, cannot best perform under time-varying traffic conditions. This paper presents an advanced dynamic merge control, called a lane-based dynamic merge control model and its operational algorithm, which is based on the optimized control thresholds that take into account the interactions among the speed, flow, and available work zone capacity. The focus of this study is on how to select the control variables and to determine their optimal thresholds in response to traffic flow dynamics. Evaluation results with extensive simulation experiments have shown the promising properties of the proposed dynamic merge control and its operational algorithm. [ABSTRACT FROM AUTHOR]

Abstract: Two diversion schemes that apportion demand between two on-ramps to reduce congestion and improve throughput on a freeway are analyzed. In the first scheme, drivers choose to merge or to divert to a downstream on-ramp based on information about average travel times for the two routes: (1) merge and travel on the freeway or (2) divert and travel on a surface street with merging downstream. The flow, rate of merging at the ramps, and the travel times oscillate strongly, but irregularly, due to delayed feedback. In the second scheme, diversion is controlled by the average mainline velocities just upstream of the on-ramps. Driver choice is not involved. If the average upstream velocity on the mainline drops below a predetermined value (20 m/s) vehicles are diverted to the downstream ramp. When the average mainline velocity downstream becomes too low, diversion is no longer permitted. The resultant oscillations in this scheme are nearly periodic. The period is dominated by the response time of the mainline to interruption of merging rather than delayed feedback, which contributes only a minor component linear in the distance separating the on-ramps. In general the second scheme produces more effective congestion reduction and greater throughput. Also the travel times for on-ramp drivers are less than that obtained by drivers who attempt to minimize their own travel times (first scheme). The simulations are done using the Kerner–Klenov stochastic three-phase theory of traffic [B.S. Kerner, S.L. Klenov, Phys. Rev. E 68 (2003) 036130]. [Copyright &y& Elsevier]

Abstract: We introduce the idea of a European-type congestion call option to value commuting to work along a given path for a given departure time selected by automobile drivers who are modeled as Cournot–Nash non-cooperative agents competing for limited roadway capacity when the alternative of telecommuting exists. We show how to compute flow patterns based on congestion call options and contrast these to traditional user optimized flow patterns. In particular, a numerical example is presented that shows congestion options have the potential to lower the network-wide social costs of congestion. [Copyright &y& Elsevier]

Abstract: There is plenty of evidence that drivers may make small changes in their time of travel to take advantage of lower levels of congestion. However, progress in the practical modelling of such “micro” re-scheduling within peak period traffic remains slow. While there exist research papers describing theoretical solutions, techniques for practical use are not generally available. Most commonly used assignment programs are temporally aggregate, while packages which do allow some “dynamic assignment” typically assume a fixed demand profile. The aim of the paper is to present a more heuristic method which could at least be used on an interim basis. The assumption is that the demand profile can be segmented into a number of mutually exclusive “windows” in relation to the “preferred arrival time”, while on the assignment side, independently defined sequential “timeslices” are used in order to respect some of the dynamic processes relating to the build-up of queues. The demand process, whereby some drivers shift away from their preferred window, leads to an iterative procedure with the aim of achieving reasonable convergence. Using the well-known scheduling theory developed by Vickrey, Small, and Arnott, de Palma & Lindsey, the basic approach can be described, extending from the simple “bottleneck”, to which the theory was originally applied, to a general network. So far, insufficient research funds have been made available to test the approach properly. It is hoped that by bringing the ideas into the public domain, further research into this area may be stimulated. [Copyright &y& Elsevier]

Abstract: The aim of the paper is to present an engineer''s viewpoint of traffic streams and their models both at the macroscopic and microscopic levels. The paper concentrates on two classes of macroscopic models (namely, stream description models and travel time estimation models). At the microscopic level the paper concentrates on car-following models and also presents a relatively recent idea on developing a comprehensive microscopic model of driver behaviour. Finally, the paper presents some properties which all microscopic models of traffic flow should possess and also tries to identify areas where research will bring about a qualitative jump in the understanding of how traffic flows. [Copyright &y& Elsevier]

Comments on the controversy of traffic congestion. Presumption concerning the consequence of greater density on the road; Assumption related to travel time as a crucial determinant for a driver to get on the road; Distinction between continuous demand and peak demand.

The article describes a computer simulation model that tracks the evacuation of cars through South Carolina's evacuation network. A simplified map of South Carolina comprising 107 junctions and 154 roads is programmed in Java. Each point in the program contains data on a city's population and regulates traffic flow into and out of the roads linked to it. A modified genetic optimization algorithm, beginning from South Carolina's current solution into the evacuation, is used. Assuming that the maximum flow of a one-lane road is 1,500 cars per hour, South Carolina's current evacuation route is tested with the modified flow equations, which allow for more people to leave the evacuation region. After 24 hours, 556,000 people are still left stranded in the cities requiring evacuation. If the lanes are reversed, the people left drops to 476,000. However, if people are allowed to take their boats and campers with them, the number of people left comes to 619,000.

The article presents a steady-state model for analyzing traffic flow in one and two lanes and addressing vehicle evacuation problem in case of emergencies. The model is based on the assumptions that driver reaction time is around one second, they tend to drive at a safe distance with minimum tailgating, and all cars, headed toward the same direction, are 10 ft long and 5 ft wide. Different terms have been designated for density, occupancy, flow, separation distance, speed, travel time, and total travel time. To determine optimal traffic flow rates, the one-dimensional cellular automata and the steady-state models have been combined to measure the relationship between speed and the separation distance. As for keeping evacuation time to a minimum, the evacuation route must be as safe as possible under the circumstances. The average time a driver takes to reach to safety is related to minimizing total evacuation time but is not equivalent.

An attempt is made to furnish plausible explanations for some observed traffic-flow phenomena, based on known behavior of a pair of cars in a car-following situation. A fundamental psychophysical approach is applied deterministically in assessing actual driver performance. Observation of driver behavior in the traffic stream indicates that there are trajectories which loop clockwise in the phase (spacing/relative speed) plane. Based on these observations, and on a car-following equation appropriate for a two-regime (free-flow and congested-flow) phenomenon, an approximate limit cycle in the phase plane (switch-type behavior) is derived. The enveloping curves to these limit cycles may represent actual relatively close .spacing conditions. It is realized that the intersection point of an approximate enveloping curve and a threshold curve for detecting relative speed at a given spacing has an important property, and may be associated with the critical spacing which represents transition between the congested-flow and free-flow regimes. [ABSTRACT FROM AUTHOR]

The paper gives conditions which guarantee the existence of an equilibrium arrival pattern at a single bottleneck. In the model, the times at which a driver wishes to leave the bottleneck depend on the driver. The equilibrium queue length in this model always has a continuous time derivative everywhere. However, the slope of the equilibrium cumulative arrival distribution is discontinuous at the beginning and end of congestion. [ABSTRACT FROM AUTHOR]

The article discusses the problems of car sharing programs and the safety aspects related to such programs. Car sharing programs provide transportation solutions to city drivers. Drivers have the convenience of hiring vehicles only during the day when they need personal transportation. The system has many benefits. The cost is lower, traffic congestion is reduced, transit time is reduced, it is more fuel efficient, and is more environment friendly as there is less emission. However, the risks involved cannot be ignored. Other than the risks normally associated with driving a motor vehicle, there are ergonomic issues, that is adjusting to the vehicle each time. The features of the vehicles also vary. In an emergency situation, this could raise the driver's risk.