Engineering › Control and Systems Engineering

Traffic control and management

Works Count: 45474

Wikipedia

Description

This cluster of papers focuses on the modeling and control of traffic flow systems, including microscopic simulation, cooperative adaptive cruise control, connected vehicles, traffic signal control, platooning, macroscopic fundamental diagram, intelligent transportation systems, vehicle dynamics model, and reinforcement learning.

Keywords

Traffic Flow; Microscopic Simulation; Cooperative Adaptive Cruise Control; Connected Vehicles; Traffic Signal Control; Platooning; Macroscopic Fundamental Diagram; Intelligent Transportation Systems; Vehicle Dynamics Model; Reinforcement Learning

ALINEA: A LOCAL FEEDBACK CONTROL LAW FOR ON-RAMP METERING

1991-01-01

Markos Papageorgiou , Habib Hadj-Salem , Jean-Marc Blosseville

ALINEA, a new local traffic-responsive strategy for ramp metering, is presented. The new control strategy is based on a feedback structure and is derived by use of classical automatic control … ALINEA, a new local traffic-responsive strategy for ramp metering, is presented. The new control strategy is based on a feedback structure and is derived by use of classical automatic control methods. ALINEA is a simple, robust, flexible, and effective local strategy for ramp metering. Real-life results from application of the new strategy to a single on-ramp of the Boulevard Peripherique in Paris are provided.

Congested traffic states in empirical observations and microscopic simulations

2000-08-01

Martin Treiber , Ansgar Hennecke , Dirk Helbing

We present data from several German freeways showing different kinds of congested traffic forming near road inhomogeneities, specifically lane closings, intersections, or uphill gradients. The states are localized or extended, … We present data from several German freeways showing different kinds of congested traffic forming near road inhomogeneities, specifically lane closings, intersections, or uphill gradients. The states are localized or extended, homogeneous or oscillating. Combined states are observed as well, like the coexistence of moving localized clusters and clusters pinned at road inhomogeneities, or regions of oscillating congested traffic upstream of nearly homogeneous congested traffic. The experimental findings are consistent with a recently proposed theoretical phase diagram for traffic near on-ramps [D. Helbing, A. Hennecke, and M. Treiber, Phys. Rev. Lett. 82, 4360 (1999)]. We simulate these situations with a continuous microscopic single-lane model, the "intelligent driver model," using empirical boundary conditions. All observations, including the coexistence of states, are qualitatively reproduced by describing inhomogeneities with local variations of one model parameter. We show that the results of the microscopic model can be understood by formulating the theoretical phase diagram for bottlenecks in a more general way. In particular, a local drop of the road capacity induced by parameter variations has essentially the same effect as an on-ramp.

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Dynamical model of traffic congestion and numerical simulation

1995-02-01

Masako Bando , Katsuya Hasebe , A. Nakayama +2 more

We present a dynamical model of traffic congestion based on the equation of motion of each vehicle. In this model, the legal velocity function is introduced, which is a function … We present a dynamical model of traffic congestion based on the equation of motion of each vehicle. In this model, the legal velocity function is introduced, which is a function of the headway of the preceding vehicle. We investigate this model with both analytic and numerical methods. The stability of traffic flow is analyzed, and the evolution of traffic congestion is observed with the development of time.

Nonlinear Effects in the Dynamics of Car Following

1961-04-01

G. F. Newell

It is assumed that the velocity of a car at time t is some (nonlinear) function of the spacial headway at time t − Δ, so the equations of motion … It is assumed that the velocity of a car at time t is some (nonlinear) function of the spacial headway at time t − Δ, so the equations of motion for a sequence of cars consists of a set of differential-difference equations. There is a special family of velocity-headway relations that agrees well with experimental data for steady flow, and that also gives differential equations which for Δ = 0 can be solved explicitly. Some exact solutions of these equations show that a small amplitude disturbance propagates through a series of cars in the manner described by linear theories except that the dependence of the wave velocity on the car velocity causes an accleration wave to spread as it propagates and a deceleration wave to form a stable shock. These conclusions are then shown to hold for quite general types of velocity-headway relations, and to yield a theory that in certain limiting cases gives all the results of the linear car-following theories and in other cases all the features of the nonlinear continuum theories, plus a detailed picture of the shock structure.

Impacts of Cooperative Adaptive Cruise Control on Freeway Traffic Flow

2012-01-01

Steven E Shladover , Dongyan Su , Xiao‐Yun Lu

This study used microscopic simulation to estimate the effect on highway capacity of varying market penetrations of vehicles with adaptive cruise control (ACC) and cooperative adaptive cruise control (CACC). Because … This study used microscopic simulation to estimate the effect on highway capacity of varying market penetrations of vehicles with adaptive cruise control (ACC) and cooperative adaptive cruise control (CACC). Because the simulation used the distribution of time gap settings that drivers from the general public used in a real field experiment, this study was the first on the effects of ACC and CACC on traffic to be based on real data on driver usage of these types of controls. The results showed that the use of ACC was unlikely to change lane capacity significantly. However, CACC was able to increase capacity greatly after its market penetration reached moderate to high percentages. The capacity increase could be accelerated by equipping non-ACC vehicles with vehicle awareness devices so that they could serve as the lead vehicles for CACC vehicles.

Cooperative Adaptive Cruise Control in Real Traffic Situations

2013-08-30

Vicente Milanés , Steven E Shladover , John Spring +3 more

Intelligent vehicle cooperation based on reliable communication systems contributes not only to reducing traffic accidents but also to improving traffic flow. Adaptive cruise control (ACC) systems can gain enhanced performance … Intelligent vehicle cooperation based on reliable communication systems contributes not only to reducing traffic accidents but also to improving traffic flow. Adaptive cruise control (ACC) systems can gain enhanced performance by adding vehicle-vehicle wireless communication to provide additional information to augment range sensor data, leading to cooperative ACC (CACC). This paper presents the design, development, implementation, and testing of a CACC system. It consists of two controllers, one to manage the approaching maneuver to the leading vehicle and the other to regulate car-following once the vehicle joins the platoon. The system has been implemented on four production Infiniti M56s vehicles, and this paper details the results of experiments to validate the performance of the controller and its improvements with respect to the commercially available ACC system.

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Full velocity difference model for a car-following theory

2001-06-22

Rui Jiang , Qing-Song Wu , Zuojin Zhu

In this paper, we present a full velocity difference model for a car-following theory based on the previous models in the literature. To our knowledge, the model is an improvement … In this paper, we present a full velocity difference model for a car-following theory based on the previous models in the literature. To our knowledge, the model is an improvement over the previous ones theoretically, because it considers more aspects in car-following process than others. This point is verified by numerical simulation. Then we investigate the property of the model using both analytic and numerical methods, and find that the model can describe the phase transition of traffic flow and estimate the evolution of traffic congestion.

Development and Evaluation of a Cooperative Vehicle Intersection Control Algorithm Under the Connected Vehicles Environment

2012-01-04

Joyoung Lee , Byungkyu Park

Under the Connected Vehicles (CV) environment, it is possible to create a Cooperative Vehicle Intersection Control (CVIC) system that enables cooperation between vehicles and infrastructure for effective intersection operations and … Under the Connected Vehicles (CV) environment, it is possible to create a Cooperative Vehicle Intersection Control (CVIC) system that enables cooperation between vehicles and infrastructure for effective intersection operations and management when all vehicles are fully automated. Assuming such a CVIC environment, this paper proposed a CVIC algorithm that does not require a traffic signal. The CVIC algorithm was designed to manipulate individual vehicles' maneuvers so that vehicles can safely cross the intersection without colliding with other vehicles. By eliminating the potential overlaps of vehicular trajectories coming from all conflicting approaches at the intersection, the CVIC algorithm seeks a safe maneuver for every vehicle approaching the intersection and manipulates each of them. An additional algorithm was designed to deal with the system failure cases resulting from inevitable trajectory overlaps at the intersection and infeasible solutions. A simulation-based case study implemented on a hypothetical four-way single-lane approach intersection under varying congestion conditions showed that the CVIC algorithm significantly improved intersection performance compared with conventional actuated intersection control: 99% and 33% of stop delay and total travel time reductions, respectively, were achieved. In addition, the CVIC algorithm significantly improved air quality and energy savings: 44% reductions of CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> and 44% savings of fuel consumption.

Traffic jams without bottlenecks—experimental evidence for the physical mechanism of the formation of a jam

2008-03-04

Yūki Sugiyama , Minoru Fukui , Macoto Kikuchi +5 more

A traffic jam on a highway is a very familiar phenomenon. From the physical viewpoint, the system of vehicular flow is a non-equilibrium system of interacting particles (vehicles). The collective … A traffic jam on a highway is a very familiar phenomenon. From the physical viewpoint, the system of vehicular flow is a non-equilibrium system of interacting particles (vehicles). The collective effect of the many-particle system induces the instability of a free flow state caused by the enhancement of fluctuations, and the transition to a jamming state occurs spontaneously if the average vehicle density exceeds a certain critical value. Thus, a bottleneck is only a trigger and not the essential origin of a traffic jam. In this paper, we present the first experimental evidence that the emergence of a traffic jam is a collective phenomenon like 'dynamical' phase transitions and pattern formation in a non-equilibrium system. We have performed an experiment on a circuit to show the emergence of a jam with no bottleneck. In the initial condition, all the vehicles are moving, homogeneously distributed on the circular road, with the same velocity. The average density of the vehicles is prepared for the onset of the instability. Even a tiny fluctuation grows larger and then the homogeneous movement cannot be maintained. Finally, a jam cluster appears and propagates backward like a solitary wave with the same speed as that of a jam cluster on a highway.

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Real-time freeway traffic state estimation based on extended Kalman filter: a general approach

2004-07-23

Yibing Wang , Markos Papageorgiou

A model for the structure of lane-changing decisions

1986-10-01

P G Gipps

Requiem for second-order fluid approximations of traffic flow

1995-08-01

Carlos F. Daganzo

Resurrection of "Second Order" Models of Traffic Flow

2000-01-01

A. Aw , M. Rascle

We introduce a new "second order" model of traffic flow. As noted in [C. Daganzo, Requiem for second-order fluid with approximation to traffic flow, Transportation Res. Part B, 29 (1995), … We introduce a new "second order" model of traffic flow. As noted in [C. Daganzo, Requiem for second-order fluid with approximation to traffic flow, Transportation Res. Part B, 29 (1995), pp. 277--286], the previous "second order" models, i.e., models with two equations (mass and "momentum"), lead to nonphysical effects, probably because they try to mimic the gas dynamics equations, with an unrealistic dependence on the acceleration with respect to the space derivative of the "pressure." We simply replace this space derivative with a convective derivative, and we show that this very simple repair completely resolves the inconsistencies of these models. Moreover, our model nicely predicts instabilities near the vacuum, i.e., for very light traffic.

On kinematic waves I. Flood movement in long rivers

1955-05-10

M. J. Lighthill , G. B. Whitham

In this paper and in part II, we give the theory of a distinctive type of wave motion, which arises in any one-dimensional flow problem when there is an approximate … In this paper and in part II, we give the theory of a distinctive type of wave motion, which arises in any one-dimensional flow problem when there is an approximate functional relation at each point between the flow q (quantity passing a given point in unit time) and concentration k (quantity per unit distance). The wave property then follows directly from the equation of continuity satisfied by q and k . In view of this, these waves are described as ‘kinematic’, as distinct from the classical wave motions, which depend also on Newton’s second law of motion and are therefore called ‘dynamic’. Kinematic waves travel with the velocity dq/dk , and the flow q remains constant on each kinematic wave. Since the velocity of propagation of each wave depends upon the value of q carried by it, successive waves may coalesce to form ‘kinematic shock waves ’. From the point of view of kinematic wave theory, there is a discontinuous increase in q at a shock, but in reality a shock wave is a relatively narrow region in which (owing to the rapid increase of q ) terms neglected by the flow concentration relation become important. The general properties of kinematic waves and shock waves are discussed in detail in §1. One example included in §1 is the interpretation of the group-velocity phenomenon in a dispersive medium as a particular case of the kinematic wave phenomenon. The remainder of part I is devoted to a detailed treatment of flood movement in long rivers, a problem in which kinematic waves play the leading role although dynamic waves (in this case, the long gravity waves) also appear. First (§2), we consider the variety of factors which can influence the approximate flow-concentration relation, and survey the various formulae which have been used in attempts to describe it. Then follows a more mathematical section (§3) in which the role of the dynamic waves is clarified. From the full equations of motion for an idealized problem it is shown that at the ‘Froude numbers’ appropriate to flood waves, the dynamic waves are rapidly attenuated and the main disturbance is carried downstream by the kinematic waves; some account is then given of the behaviour of the flow at higher Froude numbers. Also in §3, the full equations of motion are used to investigate the structure of the kinematic shock; for this problem, the shock is the ‘monoclinal flood wave’ which is well known in the literature of this subject. The final sections (§§4 and 5) contain the application of the theory of kinematic waves to the determination of flood movement. In §4 it is shown how the waves (including shock waves) travelling downstream from an observation point may be deduced from a knowledge of the variation with time of the flow at the observation point; this section then concludes with a brief account of the effect on the waves of tributaries and run-off. In §5, the modifications (similar to diffusion effects) which arise due to the slight dependence of the flow-concentration curve on the rate of change of flow or concentration, are described and methods for their inclusion in the theory are given.

The cell transmission model, part II: Network traffic

1995-04-01

Carlos F. Daganzo

Urban gridlock: Macroscopic modeling and mitigation approaches

2006-05-09

Carlos F. Daganzo

Generalized force model of traffic dynamics

1998-07-01

Dirk Helbing , Benno Tilch

Floating car data of car-following behavior in cities were compared to existing microsimulation models, after their parameters had been calibrated to the experimental data. With these parameter values, additional simulations … Floating car data of car-following behavior in cities were compared to existing microsimulation models, after their parameters had been calibrated to the experimental data. With these parameter values, additional simulations have been carried out, e.g., of a moving car which approaches a stopped car. It turned out that, in order to manage such kinds of situations without producing accidents, improved traffic models are needed. Good results were obtained with the proposed generalized force model.

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The cell transmission model: A dynamic representation of highway traffic consistent with the hydrodynamic theory

1994-08-01

Carlos F. Daganzo

The physics of traffic jams

2002-08-13

Takashi Nagatani

Traffic flow is a kind of many-body system of strongly interacting vehicles. Traffic jams are a typical signature of the complex behaviour of vehicular traffic. Various models are presented to … Traffic flow is a kind of many-body system of strongly interacting vehicles. Traffic jams are a typical signature of the complex behaviour of vehicular traffic. Various models are presented to understand the rich variety of physical phenomena exhibited by traffic. Analytical and numerical techniques are applied to study these models. Particularly, we present detailed results obtained mainly from the microscopic car-following models. A typical phenomenon is the dynamical jamming transition from the free traffic (FT) at low density to the congested traffic at high density. The jamming transition exhibits the phase diagram similar to a conventional gas-liquid phase transition: the FT and congested traffic correspond to the gas and liquid phases, respectively. The dynamical transition is described by the time-dependent Ginzburg-Landau equation for the phase transition. The jamming transition curve is given by the spinodal line. The metastability exists in the region between the spinodal and phase separation lines. The jams in the congested traffic reveal various density waves. Some of these density waves show typical nonlinear waves such as soliton, triangular shock and kink. The density waves are described by the nonlinear wave equations: the Korteweg-de-Vries (KdV) equation, the Burgers equation and the Modified KdV equation. Subjects like the traffic flow such as bus-route system and pedestrian flow are touched as well. The bus-route system with many buses exhibits the bunching transition where buses bunch together with proceeding ahead. Such dynamic models as the car-following model are proposed to investigate the bunching transition and bus delay. A recurrent bus exhibits the dynamical transition between the delay and schedule-time phases. The delay transition is described in terms of the nonlinear map. The pedestrian flow also reveals the jamming transition from the free flow at low density to the clogging at high density. Some models are presented to study the pedestrian flow. When the clogging occurs, the pedestrian flow shows the scaling behaviour.

A simplified theory of kinematic waves in highway traffic, part I: General theory

1993-08-01

G. F. Newell

Traffic Dynamics: Studies in Car Following

1958-04-01

Robert E. Chandler , Robert K Herman , Elliott W. Montroll

The manner in which vehicles follow each other on a highway (without passing) and the propagation disturbances down a line of vehicles has been investigated. Experimental data is presented which … The manner in which vehicles follow each other on a highway (without passing) and the propagation disturbances down a line of vehicles has been investigated. Experimental data is presented which indicates that the acceleration at time t of a car which is attempting to follow a leader is proportional to the difference in velocity of the two cars at a time (t − Δ), Δ being about 1.5 sec and the proportionality constant being about 0.37 sec −1 . It is shown theoretically that the motion of a long line of vehicles becomes unstable when the product of the lag time and the proportionality constant exceeds one-half. The experimental data implies that driving is done on the verge of instability. A variety of other laws of following is analyzed theoretically.

A simplified car-following theory: a lower order model

2002-03-01

G. F. Newell

General Lane-Changing Model MOBIL for Car-Following Models

2007-01-01

Arne Kesting , Martin Treiber , Dirk Helbing

A general model (minimizing overall braking induced by lane change, MOBIL) is proposed to derive lane-changing rules for discretionary and mandatory lane changes for a wide class of car-following models. … A general model (minimizing overall braking induced by lane change, MOBIL) is proposed to derive lane-changing rules for discretionary and mandatory lane changes for a wide class of car-following models. Both the utility of a given lane and the risk associated with lane changes are determined in terms of longitudinal accelerations calculated with microscopic traffic models. This determination allows for the formulation of compact and general safety and incentive criteria for both symmetric and asymmetric passing rules. Moreover, anticipative elements and the crucial influence of velocity differences of these car-following models are automatically transferred to the lane-changing rules. Although the safety criterion prevents critical lane changes and collisions, the incentive criterion takes into account the advantages and disadvantages of other drivers associated with a lane change via the “politeness factor.” The parameter allows one to vary the motivation for lane changing from purely egoistic to more cooperative driving behavior. This novel feature allows one first to prevent lane changes for a marginal advantage if they obstruct other drivers and second to let an aggressive driver induce the lane change of a slower driver ahead in order to no longer be obstructed. This phenomenon is common for asymmetric passing rules with a dedicated lane for passing. The model is applied to traffic simulations of cars and trucks with the intelligent driver model as the underlying car-following model. An open system with an on-ramp is studied, and the resulting lane-changing rate is investigated as a function of the spatial coordinate as well as a function of traffic density.

A Microscopic Traffic Simulator for evaluation of dynamic traffic management systems

1996-06-01

Qi Yang , Haris N. Koutsopoulos

An Analysis of Traffic Flow

1959-02-01

Harold Greenberg

A model for traffic flow is developed by treating the traffic stream as a continuous fluid. Fluid dynamic principles are then used to derive relations between speed, density, and flow. A model for traffic flow is developed by treating the traffic stream as a continuous fluid. Fluid dynamic principles are then used to derive relations between speed, density, and flow.

Traffic Dynamics: Analysis of Stability in Car Following

1959-02-01

Robert K Herman , Elliott W. Montroll , Renfrey B. Potts +1 more

The manner in which vehicles follow each other on a highway (without passing) and the propagation of disturbances down a line of vehicles has been investigated further. Criteria are derived … The manner in which vehicles follow each other on a highway (without passing) and the propagation of disturbances down a line of vehicles has been investigated further. Criteria are derived for both local and asymptotic stability in a chain of vehicles. The influence of next nearest neighbors as well as a statistical theory of stability is discussed. “Acceleration noise” is proposed as a parameter that might be employed to characterize the driver-car-road complex under various conditions. Some preliminary experimental measurements of acceleration noise are discussed.

An Operational Analysis of Traffic Dynamics

1953-03-01

Louis A. Pipes

The dynamics of a line of traffic composed of n vehicles is studied mathematically. It is postulated that the movements of the several vehicles are controlled by an idealized ``law … The dynamics of a line of traffic composed of n vehicles is studied mathematically. It is postulated that the movements of the several vehicles are controlled by an idealized ``law of separation.'' The law considered in the analysis specifies that each vehicle must maintain a certain prescribed ``following distance'' from the preceding vehicle. This distance is the sum of a distance proportional to the velocity of the following vehicle and a certain given minimum distance of separation when the vehicles are at rest. By the application of this postulated law to the motion of the column of vehicles, the differential equations governing the dynamic state of the system are obtained. The solution of the dynamical equations for several assumed types of motion of the leading vehicle is effected by the operational or Laplace transform method and the velocities and accelerations of the various vehicles are thus obtained. Consideration is given to the use of an electrical analog computer for studying the dynamical equations of the system.

Modeling cooperative and autonomous adaptive cruise control dynamic responses using experimental data

2014-09-30

Vicente Milanés , Steven E Shladover

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Kinetic Theory of Vehicular Traffic

1972-04-01

Ilya Prigogine , R. Herman , R. S. Schechter

THE THEORY OF MULTIPLE-LANE TRAFFIC FLOW IS EXAMINED. A PREDICTION OF THE CHARACTER OF THE TRAFFIC FLOW IS MADE AT ARBITARY DENSITY IN TERMS OF DRIVER BEHAVIOR IN DILUTE, NONINTERACTING … THE THEORY OF MULTIPLE-LANE TRAFFIC FLOW IS EXAMINED. A PREDICTION OF THE CHARACTER OF THE TRAFFIC FLOW IS MADE AT ARBITARY DENSITY IN TERMS OF DRIVER BEHAVIOR IN DILUTE, NONINTERACTING TRAFFIC, AND A KINETIC EQUATION IS DERIVED TO DESCRIBE THE SPACE-TIME EVOLUTION OF THE VELOCITY DISTRIBUTION OF CARS. THE ANALOGIES THAT EXIST BETWEEN STATISTICAL PHYSICS AND TRAFFIC HAVE BEEN EMPLOYED IN DEVELOPING A VIABLE THEORY. THE PROBLEM IS FORMULATED AND THE THEORY IS DEVELOPED TO A POINT WHERE THE MEETING OF THEORETICAL CONCEPTS WITH EXPERIMENTAL OBSERVATIONS WILL BE FRUITFUL. /AUTHOR/

A behavioural car-following model for computer simulation

1981-04-01

P G Gipps

Shock Waves on the Highway

1956-02-01

P.I. Richards

A simple theory of traffic flow is developed by replacing individual vehicles with a continuous “fluid” density and applying an empirical relation between speed and density. Characteristic features of the … A simple theory of traffic flow is developed by replacing individual vehicles with a continuous “fluid” density and applying an empirical relation between speed and density. Characteristic features of the resulting theory are a simple “graph-shearing” process for following the development of traffic waves in time and the frequent appearance of shock waves. The effect of a traffic signal on traffic streams is studied and found to exhibit a threshold effect wherein the disturbances are minor for light traffic but suddenly build to large values when a critical density is exceeded.

Car-following: a historical review

1999-12-01

Mark Brackstone , Mike McDonald

On kinematic waves II. A theory of traffic flow on long crowded roads

1955-05-10

M. J. Lighthill , G. B. Whitham

This paper uses the method of kinematic waves, developed in part I, but may be read independently. A functional relationship between flow and concentration for traffic on crowded arterial roads … This paper uses the method of kinematic waves, developed in part I, but may be read independently. A functional relationship between flow and concentration for traffic on crowded arterial roads has been postulated for some time, and has experimental backing (§2). From this a theory of the propagation of changes in traffic distribution along these roads may be deduced (§§2, 3). The theory is applied (§4) to the problem of estimating how a ‘hump’, or region of increased concentration, will move along a crowded main road. It is suggested that it will move slightly slower than the mean vehicle speed, and that vehicles passing through it will have to reduce speed rather suddenly (at a ‘shock wave’) on entering it, but can increase speed again only very gradually as they leave it. The hump gradually spreads out along the road, and the time scale of this process is estimated. The behaviour of such a hump on entering a bottleneck, which is too narrow to admit the increased flow, is studied (§5), and methods are obtained for estimating the extent and duration of the resulting hold-up. The theory is applicable principally to traffic behaviour over a long stretch of road, but the paper concludes (§6) with a discussion of its relevance to problems of flow near junctions, including a discussion of the starting flow at a controlled junction. In the introductory sections 1 and 2, we have included some elementary material on the quantitative study of traffic flow for the benefit of scientific readers unfamiliar with the subject.

Autonomous intelligent cruise control

1993-01-01

Pétros Ioannou , Chih‐Ching Chien

Vehicle following and its effects on traffic flow has been an active area of research. Human driving involves reaction times, delays, and human errors that affect traffic flow adversely. One … Vehicle following and its effects on traffic flow has been an active area of research. Human driving involves reaction times, delays, and human errors that affect traffic flow adversely. One way to eliminate human errors and delays in vehicle following is to replace the human driver with a computer control system and sensors. The purpose of this paper is to develop an autonomous intelligent cruise control (AICC) system for automatic vehicle following, examine its effect on traffic flow, and compare its performance with that of the human driver models. The AICC system developed is not cooperative; i.e., it does not exchange information with other vehicles and yet is not susceptible to oscillations and "slinky" effects. The elimination of the "slinky" effect is achieved by using a safety distance separation rule that is proportional to the vehicle velocity (constant time headway) and by designing the control system appropriately. The performance of the AICC system is found to be superior to that of the human driver models considered. It has a faster and better transient response that leads to a much smoother and faster traffic flow. Computer simulations are used to study the performance of the proposed AICC system and analyze vehicle following in a single lane, without passing, under manual and automatic control. In addition, several emergency situations that include emergency stopping and cut-in cases were simulated. The simulation results demonstrate the effectiveness of the AICC system and its potentially beneficial effects on traffic flow.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>

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Nonlinear Follow-the-Leader Models of Traffic Flow

1961-08-01

Denos C. Gazis , Robert K Herman , Richard Rothery

A variety of nonlinear follow-the-leader models of traffic flow are discussed in the light of available observational and experimental data. Emphasis is placed on steady-state flow equations. Some trends regarding … A variety of nonlinear follow-the-leader models of traffic flow are discussed in the light of available observational and experimental data. Emphasis is placed on steady-state flow equations. Some trends regarding the advantages of certain follow-the-leader functionals over others are established. However, it is found from extensive correlation studies that more data are needed before one can establish the unequivocal superiority of one particular model. A discussion is given of some ideas concerning the possible reasons for the existence of a bimodal flow versus concentration curve especially for multilane highways.

A non-equilibrium traffic model devoid of gas-like behavior

2002-03-01

H.M. Zhang

The Impact of Cooperative Adaptive Cruise Control on Traffic-Flow Characteristics

2006-12-01

Bart van Arem , C.J.G. van Driel , Ruben Visser

Cooperative adaptive cruise control (CACC) is an extension of ACC. In addition to measuring the distance to a predecessor, a vehicle can also exchange information with a predecessor by wireless … Cooperative adaptive cruise control (CACC) is an extension of ACC. In addition to measuring the distance to a predecessor, a vehicle can also exchange information with a predecessor by wireless communication. This enables a vehicle to follow its predecessor at a closer distance under tighter control. This paper focuses on the impact of CACC on traffic-flow characteristics. It uses the traffic-flow simulation model MIXIC that was specially designed to study the impact of intelligent vehicles on traffic flow. The authors study the impacts of CACC for a highway-merging scenario from four to three lanes. The results show an improvement of traffic-flow stability and a slight increase in traffic-flow efficiency compared with the merging scenario without equipped vehicles

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String-Stable CACC Design and Experimental Validation: A Frequency-Domain Approach

2010-09-15

Gerrit Naus , Rene P A Vugts , Jeroen Ploeg +2 more

The design of a cooperative adaptive cruise-control (CACC) system and its practical validation are presented. Focusing on the feasibility of implementation, a decentralized controller design with a limited communication structure … The design of a cooperative adaptive cruise-control (CACC) system and its practical validation are presented. Focusing on the feasibility of implementation, a decentralized controller design with a limited communication structure is proposed (in this case, a wireless communication link with the nearest preceding vehicle only). A necessary and sufficient frequency-domain condition for string stability is derived, taking into account heterogeneous traffic, i.e., vehicles with possibly different characteristics. For a velocity-dependent intervehicle spacing policy, it is shown that the wireless communication link enables driving at small intervehicle distances, whereas string stability is guaranteed. For a constant velocity-independent intervehicle spacing, string stability cannot be guaranteed. To validate the theoretical results, experiments are performed with two CACC-equipped vehicles. Implementation of the CACC system, the string-stability characteristics of the practical setup, and experimental results are discussed, indicating the advantages of the design over standard adaptive-cruise-control functionality.

A Multiagent Approach to Autonomous Intersection Management

2008-03-31

Kurt Dresner , Peter Stone

Artificial intelligence research is ushering in a new era of sophisticated, mass-market transportation technology. While computers can already fly a passenger jet better than a trained human pilot, people are … Artificial intelligence research is ushering in a new era of sophisticated, mass-market transportation technology. While computers can already fly a passenger jet better than a trained human pilot, people are still faced with the dangerous yet tedious task of driving automobiles. Intelligent Transportation Systems (ITS) is the field that focuses on integrating information technology with vehicles and transportation infrastructure to make transportation safer, cheaper, and more efficient. Recent advances in ITS point to a future in which vehicles themselves handle the vast majority of the driving task. Once autonomous vehicles become popular, autonomous interactions amongst multiple vehicles will be possible. Current methods of vehicle coordination, which are all designed to work with human drivers, will be outdated. The bottleneck for roadway efficiency will no longer be the drivers, but rather the mechanism by which those drivers' actions are coordinated. While open-road driving is a well-studied and more-or-less-solved problem, urban traffic scenarios, especially intersections, are much more challenging. We believe current methods for controlling traffic, specifically at intersections, will not be able to take advantage of the increased sensitivity and precision of autonomous vehicles as compared to human drivers. In this article, we suggest an alternative mechanism for coordinating the movement of autonomous vehicles through intersections. Drivers and intersections in this mechanism are treated as autonomous agents in a multiagent system. In this multiagent system, intersections use a new reservation-based approach built around a detailed communication protocol, which we also present. We demonstrate in simulation that our new mechanism has the potential to significantly outperform current intersection control technology -- traffic lights and stop signs. Because our mechanism can emulate a traffic light or stop sign, it subsumes the most popular current methods of intersection control. This article also presents two extensions to the mechanism. The first extension allows the system to control human-driven vehicles in addition to autonomous vehicles. The second gives priority to emergency vehicles without significant cost to civilian vehicles. The mechanism, including both extensions, is implemented and tested in simulation, and we present experimental results that strongly attest to the efficacy of this approach.

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Review of road traffic control strategies

2003-11-20

Markos Papageorgiou , C. Kiakaki , Vaya Dinopoulou +2 more

Traffic congestion in urban road and freeway networks leads to a strong degradation of the network infrastructure and accordingly reduced throughput, which can be countered via suitable control measures and … Traffic congestion in urban road and freeway networks leads to a strong degradation of the network infrastructure and accordingly reduced throughput, which can be countered via suitable control measures and strategies. After illustrating the main reasons for infrastructure deterioration due to traffic congestion, a comprehensive overview of proposed and implemented control strategies is provided for three areas: urban road networks, freeway networks, and route guidance. Selected application results, obtained from either simulation studies or field implementations, are briefly outlined to illustrate the impact of various control actions and strategies. The paper concludes with a brief discussion of future needs in this important technical area.

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Freeway ramp metering: an overview

2002-12-01

Markos Papageorgiou , Apostolos Kotsialos

Recurrent and nonrecurrent congestion on freeways may be alleviated if today's "spontaneous" infrastructure utilization is replaced by an orderly, controllable operation via comprehensive application of ramp metering and freeway-to-freeway control, … Recurrent and nonrecurrent congestion on freeways may be alleviated if today's "spontaneous" infrastructure utilization is replaced by an orderly, controllable operation via comprehensive application of ramp metering and freeway-to-freeway control, combined with powerful optimal control techniques. This paper first explains why ramp metering can lead to a dramatic amelioration of traffic conditions on freeways. An overview of ramp metering algorithms is provided next, ranging from early fixed-time approaches to traffic-responsive regulators and to modern sophisticated nonlinear optimal control schemes. Finally, a large-scale example demonstrates the high potential of advanced ramp metering approaches.

Predictive Cruise Control: Utilizing Upcoming Traffic Signal Information for Improving Fuel Economy and Reducing Trip Time

2010-04-30

Behrang Asadi , Ardalan Vahidi

This brief proposes the use of upcoming traffic signal information within the vehicle's adaptive cruise control system to reduce idle time at stop lights and fuel consumption. To achieve this … This brief proposes the use of upcoming traffic signal information within the vehicle's adaptive cruise control system to reduce idle time at stop lights and fuel consumption. To achieve this goal an optimization-based control algorithm is formulated that uses short range radar and traffic signal information predictively to schedule an optimum velocity trajectory for the vehicle. The control objectives are: timely arrival at green light with minimal use of braking, maintaining safe distance between vehicles, and cruising at or near set speed. Three example simulation case studies are presented to demonstrate the potential impact on fuel economy, emission levels, and trip time.

Traffic Flow Dynamics

2012-10-09

Martin Treiber , Arne Kesting

Influence of connected and autonomous vehicles on traffic flow stability and throughput

2016-07-27

Alireza Talebpour , Hani S. Mahmassani

A Survey on the Coordination of Connected and Automated Vehicles at Intersections and Merging at Highway On-Ramps

2016-09-07

Jackeline Rios-Torres , Andreas A. Malikopoulos

Connected and automated vehicles (CAVs) have the potential to improve safety by reducing and mitigating traffic accidents. They can also provide opportunities to reduce transportation energy consumption and emissions by … Connected and automated vehicles (CAVs) have the potential to improve safety by reducing and mitigating traffic accidents. They can also provide opportunities to reduce transportation energy consumption and emissions by improving traffic flow. Vehicle communication with traffic structures and traffic lights can allow individual vehicles to optimize their operation and account for unpredictable changes. This paper summarizes the developments and the research trends in coordination with the CAVs that have been reported in the literature to date. Remaining challenges and potential future research directions are also discussed.

Dissipation of stop-and-go waves via control of autonomous vehicles: Field experiments

2018-02-20

Raphael Stern , Shumo Cui , Maria Laura Delle Monache +7 more

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Microscopic Traffic Simulation using SUMO

2018-11-01

Pablo Álvarez López , Evamarie Wießner , Michael Behrisch +7 more

Microscopic traffic simulation is an invaluable tool for traffic research. In recent years, both the scope of research and the capabilities of the tools have been extended considerably. This article … Microscopic traffic simulation is an invaluable tool for traffic research. In recent years, both the scope of research and the capabilities of the tools have been extended considerably. This article presents the latest developments concerning intermodal traffic solutions, simulator coupling and model development and validation on the example of the open source traffic simulator SUMO.

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Multi-Agent Deep Reinforcement Learning for Large-Scale Traffic Signal Control

2019-03-15

Tianshu Chu , Jie Wang , Lara Codecà +1 more

Reinforcement learning (RL) is a promising data-driven approach for adaptive traffic signal control (ATSC) in complex urban traffic networks, and deep neural networks further enhance its learning power. However, the … Reinforcement learning (RL) is a promising data-driven approach for adaptive traffic signal control (ATSC) in complex urban traffic networks, and deep neural networks further enhance its learning power. However, the centralized RL is infeasible for large-scale ATSC due to the extremely high dimension of the joint action space. The multi-agent RL (MARL) overcomes the scalability issue by distributing the global control to each local RL agent, but it introduces new challenges: now, the environment becomes partially observable from the viewpoint of each local agent due to limited communication among agents. Most existing studies in MARL focus on designing efficient communication and coordination among traditional Q-learning agents. This paper presents, for the first time, a fully scalable and decentralized MARL algorithm for the state-of-the-art deep RL agent, advantage actor critic (A2C), within the context of ATSC. In particular, two methods are proposed to stabilize the learning procedure, by improving the observability and reducing the learning difficulty of each local agent. The proposed multi-agent A2C is compared against independent A2C and independent Q-learning algorithms, in both a large synthetic traffic grid and a large real-world traffic network of Monaco city, under simulated peak-hour traffic dynamics. The results demonstrate its optimality, robustness, and sample efficiency over the other state-of-the-art decentralized MARL algorithms.

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Balancing Bus Punctuality and Heterogeneous Flow Stability Under a Connected Environment

2025-06-25

Lichao Wang , Ziyi Zhou , Shaohua Cui | Automotive Innovation

Lane-change leading strategy for CAV-dedicated lanes in mixed traffic environments considering human driver randomness and compliance

2025-06-25

Guosheng Xiao , Yangsheng Jiang , Zhaoqing Li +1 more | Transportation Research Part C Emerging Technologies

EFFECTIVENESS OF IMITATION METHODS IN ESTIMATING THE DELAY TIME OF VEHICLES AT INTERSECTION

2025-06-25

Turan Verdiyev | Elmi Əsərlər

The article highlights the importance of simulation models in developing solutions for traffic management, and analyzes studies devoted to the use of simulation programs in solving transport problems. It is … The article highlights the importance of simulation models in developing solutions for traffic management, and analyzes studies devoted to the use of simulation programs in solving transport problems. It is emphasized that despite the widespread application of simulation methods, their comparison with theoretical calculations is not carried out. In this work, the delay times of vehicles at an intersection with a 3-phase traffic light regulation in Baku city are evaluated and compared theoretically and through simulation experiments. The methodology for establishing the movement of vehicles and the operation of traffic lights at an intersection using the Anylogic program for conducting a simulation experiment is explained.

Adaptive cruise control design for enhancing stability

2025-06-25

Yunxia Wu , Le Li , Yi Wang +3 more | Urban Lifeline

Abstract This paper proposes an optimal design method for the adaptive cruise control model to enhance the string stability with the adaptive cruise control (ACC). First, the influence of control … Abstract This paper proposes an optimal design method for the adaptive cruise control model to enhance the string stability with the adaptive cruise control (ACC). First, the influence of control gain parameters on ACC and cooperative adaptive cruise control (CACC) systems is analyzed from theoretical and numerical perspectives. Second, we compared the ACC and CACC models. On this basis, an optimal control gain parameter is proposed to consider the string stability of the ACC platoon system. Finally, we designed numerical simulation experiments to verify the effectiveness of the proposed ACC (PACC) model. Results show that compared with the classical ACC model, the PACC model has certain advantages in recovery time, vehicle average velocity, velocity standard deviation, and vehicle collision safety. Moreover, PACC is suitable for most equilibrium velocity scenarios, and it has good string stability with different time gaps, unlike the ACC and CACC models. As a result, the PACC model has better string stability and robustness. Therefore, the PACC model can enhance the string stability and provide theoretical support for designing better ACC systems.

Development of a Monocular Camera-based Relative Distance and Speed Estimation Model for End-to-end Adaptive Cruise Control

2025-06-24

Jeong-hyeon Kim , Hansol Kim | Journal of Institute of Control Robotics and Systems

Impact of commercial adaptive cruise control on highway traffic congestion and safety

2025-06-23

Hwapyeong Yu , Hwasoo Yeo | Transportmetrica B Transport Dynamics

Multi-objective trajectory planning for connected and autonomous vehicles in mixed traffic flow

2025-06-23

Hui Li , Yunfei Ge , Yahui Guo +2 more | Journal of Engineering and Applied Science

Abstract As urban traffic complexity continues to rise, challenges related to traffic efficiency, fuel consumption, and safety are becoming increasingly critical. These issues underline the need for multi-objective trajectory optimization … Abstract As urban traffic complexity continues to rise, challenges related to traffic efficiency, fuel consumption, and safety are becoming increasingly critical. These issues underline the need for multi-objective trajectory optimization models, particularly in environments where both automated and human-driven vehicles coexist. Therefore, this paper developed a multi-objective trajectory planning model utilizing the TD3 algorithm. Here, we design the state space, action space, and reward function, where the state space encompasses variables such as speed, relative speed, distance to the stop line, relative position, phase state, and remaining phase duration, and the action space outputs optimal acceleration and deceleration. The reward function integrates multiple objectives, including safety, fuel consumption, and traffic efficiency. The model is verified using the SUMO tool, examining different levels of CAV penetration and varying traffic flows. The results demonstrate that as CAV penetration increases, vehicle trajectories become increasingly smooth, leading to reductions in average travel time, fuel consumption, and queue length. Specifically, at 100% CAV penetration with a traffic flow of 600 pcu/h, the highest optimization rate for average travel time reaches 15.38%. For average fuel consumption, the peak optimization rate of 19.53% occurs at a traffic flow of 800 pcu/h. Furthermore, under conditions of 300 pcu/h and 400 pcu/h traffic flow, 100% CAV penetration eliminates queues entirely. Beyond 400 pcu/h, minimal queues form with 100% CAV penetration. These results indicate that autonomous driving technology can effectively enhance the efficiency and sustainability of transportation systems, providing robust support for urban traffic management strategies. In particular, under high-density and mixed traffic conditions, the trajectory optimization model significantly improves traffic flow, reduces congestion, decreases energy consumption, and lowers the incidence of traffic accidents, thereby offering a theoretical foundation for the implementation of intelligent transportation systems.

Continuous transport systems in public passenger transport

2025-06-22

Pavle Pitka , Tatjana Kovačević , Milan Simeunović +2 more | Put i saobraćaj

In densely populated urban areas, there is an ongoing effort to curtail car usage and to promote innovative modes of transport. This paper presents a study of subsystems for specialised … In densely populated urban areas, there is an ongoing effort to curtail car usage and to promote innovative modes of transport. This paper presents a study of subsystems for specialised passenger transport, including escalators and moving walkways, and their respective characteristics and operating technologies. A global perspective reveals that the integration of escalators and moving walkways has led to substantial enhancements in the efficiency and passenger experience in airports, railways, and metro stations. A comparative analysis reveals that accelerating moving walkways offer distinct advantages over traditional public transport systems, including reduced waiting times, enhanced accuracy, increased comfort and a more appealing user experience. However, they are characterised by low speed, low spatial flexibility and lack of protection from atmospheric precipitation.

Simulation-Based Capacity and Delay Analysis of Unsignalized Intersections in Mixed Traffic Conditions

2025-06-22

Sruthi Sekhar Pallela , Ramesh Babu Kota | Journal of The Institution of Engineers (India) Series A

Fairness Criteria in Multi-Agent Systems: Optimizing Autonomous Traffic Management Through the Hierarchical Stackelberg Strategy

2025-06-21

Atef Gharbi , Mohamed Ayari , Nadhir Ben Halima +2 more | Applied Sciences

As urban traffic density and congestion increase, effective urban traffic management becomes increasingly challenging, negatively impacting travel times and the overall efficiency of transportation systems. In this paper, a hierarchical … As urban traffic density and congestion increase, effective urban traffic management becomes increasingly challenging, negatively impacting travel times and the overall efficiency of transportation systems. In this paper, a hierarchical Stackelberg model is presented to address both priority for emergency vehicles (EVs) and fairness for other vehicles. This model involves the Traffic Management Center (TMC) as the top-level authority, with emergency vehicles as the first-level leaders and regular vehicles (RVs) as the second-level followers. The multilevel decision-making structure enables real-time adjustments to prioritize critical traffic and ensure equitable treatment for regular traffic. Simulations were conducted under various traffic scenarios, including normal conditions, emergency vehicle priority, and peak traffic congestion. According to the results, the hierarchical Stackelberg model outperforms traditional models in terms of reducing average travel time, waiting time, and congestion. The model also incorporates fairness metrics such as Gini coefficients and skewness to ensure that regular vehicles are not disproportionately affected by emergency vehicle priority. According to these findings, the hierarchical Stackelberg model improves both traffic efficiency and fairness in complex urban environments, positioning it as a promising solution.

Model-Based Deep Reinforcement Learning for Energy Efficient Routing of a Connected and Automated Vehicle

2025-06-21

David Leech , Hwan‐Sik Yoon | Sustainability

The emergence of connected and automated vehicles (CAVs) offers promising opportunities to enhance traffic control and improve overall transportation system performance. However, the complexity and dynamic nature of modern traffic … The emergence of connected and automated vehicles (CAVs) offers promising opportunities to enhance traffic control and improve overall transportation system performance. However, the complexity and dynamic nature of modern traffic networks pose significant challenges for traditional routing methods. To achieve optimal vehicle routing and support sustainable mobility, more adaptive and intelligent strategies are needed. Among recent advancements, model-based deep reinforcement learning has shown exceptional potential in solving complex decision-making problems across various domains. Leveraging this capability, the present study applies a model-based deep reinforcement learning approach to address the energy-efficient routing problem in a simulated CAV environment. The routes recommended by the algorithm are compared to the shortest route calculated by traffic simulation software. The simulation results show a significant improvement in energy efficiency when the vehicle follows the routes suggested by the learning algorithm, even when the vehicle is subjected to new traffic scenarios. In addition, a comparison of the model-based agent with a conventional model-free reinforcement learning agent across varied traffic conditions demonstrates the robustness of the model-based algorithm. This work represents the first application of a model-based deep reinforcement learning algorithm to the energy-efficient routing problem for CAVs. This work also showcases a novel application of the foundational algorithm AlphaGo Zero.

An Efficient Parallelization of Microscopic Traffic Simulation

2025-06-20

Benyamin Heidary , Joerg Schweizer , Ngoc An Nguyen +2 more | Applied Sciences

Large-scale traffic simulations at a microscopic level can mimic the physical reality in great detail so that innovative transport services can be evaluated. However, the simulation times of such scenarios … Large-scale traffic simulations at a microscopic level can mimic the physical reality in great detail so that innovative transport services can be evaluated. However, the simulation times of such scenarios is currently too long to be practical. (1) Background: With the availability of Graphical Processing Units (GPUs), is it possible to exploit parallel computing to reduce the simulation times of large microscopic simulations, such that they can run on normal PCs at reasonable runtimes?; (2) Methods: ParSim, a microsimulator with a monolithic microsimulation kernel, has been developed for CUDA-compatible GPUs, with the aim to efficiently parallelize the simulation processes; particular care has been taken regarding the memory usage and thread synchronization, and visualization software has been optionally added; (3) Results: The parallelized simulations have been performed by a GPU with an average performance, a 24 h microsimulation scenario for Bologna with 1 million trips was completed in 40 s. The average speeds and waiting times are similar to the results from an established microsimulator (SUMO), but the execution time is up to 5000 times faster with respect to SUMO; the 28 million trips of the 24 h San Francisco Bay Area scenario was completed in 26 min. With cutting-edge GPUs, the simulation speed can possibly be further reduced by a factor of seven; (4) Conclusions: The parallelized simulator presented in this paper can perform large-scale microsimulations in a reasonable time on readily available and inexpensive computer hardware. This means microsimulations could now be used in new application fields such as activity-based demand generation, reinforced AI learning, traffic forecasting, or crisis response management.

Stochastic traffic signal optimization and robust vehicle trajectory control in uncertain mixed traffic flow

2025-06-20

Meiqi Liu , Liang Xu , Ge Guo +1 more | Transportation Research Part C Emerging Technologies

A cascaded strategy-based hierarchical reinforcement learning algorithm for lane change decision-making

2025-06-20

Heng Du , D. X. Lin , Xiaolong Zhang +5 more | Engineering Applications of Artificial Intelligence

Optimizing Energy Efficiency in Autonomous Vehicle Platoons Using Deep Reinforcement Learning

2025-06-19

Abu Tayab , Yanwen Li , Ahmad Syed +1 more | CRC Press eBooks

Management strategy for the maximum platoon size of connected automated vehicles in a freeway lane: A mixed traffic capacity modeling approach

2025-06-19

Yanyan Qin , Changqing Liu , S. Yan +1 more | Transportation Research Part E Logistics and Transportation Review

Analysis of stability and cooperation in traffic flow with connected automated vehicles under perceptual uncertainty

2025-06-19

Bojian Zhou , Shihao Li , Shuaiqi Wang +1 more | Chaos Solitons & Fractals

Feedback control of a heterogeneous lattice hydrodynamic model with multi-visual field effect under cyber-attacks

2025-06-18

Yanfeng Qiao , Yu Xue , Ronghan Yao +3 more | Physica A Statistical Mechanics and its Applications

Online adaptive platoon control for connected and automated vehicles via physics enhanced residual learning

2025-06-18

Yuanjian Zhang , Heye Huang , Hang Zhou +3 more | Transportation Research Part C Emerging Technologies

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A Novel Max-Pressure-Driven Integrated Ramp Metering and Variable Speed Limit Control for Port Motorways

2025-06-18

Weiqi Yue , Hangsheng Yang , Yibing Wang +3 more | Sustainability

In recent years, congestion on port motorways has become increasingly frequent, significantly constraining transportation efficiency and contributing to higher pollution emissions. This paper proposes a novel max-pressure-driven integrated control (IFC-MP) … In recent years, congestion on port motorways has become increasingly frequent, significantly constraining transportation efficiency and contributing to higher pollution emissions. This paper proposes a novel max-pressure-driven integrated control (IFC-MP) for port motorways, inspired by the max pressure (MP) concept, which continuously adjusts the weights of ramp metering (RM) and the variable speed limit (VSL) based on pressure feedback from the on-ramp and upstream, assigning greater control weight to the side with higher pressure. A queue management mechanism is incorporated to prevent on-ramp overflow. The effectiveness of IFC-MP is verified in SUMO, filling the gap where the previous integrated control methods for port motorways lacked micro-simulation validation. The results show that IFC-MP enhances bottleneck throughput by approximately 7% compared to the no-control case, optimizes the total time spent (TTS) by 26–27%, and improves total pollutant emissions (TPEs) by about 11%. Compared to strategies that use only RM and VSL control, or activate VSL control only after RM reaches its lower bound, the time–space distribution of speed under IFC-MP is more uniform, with smaller fluctuations in bottleneck occupancy. Additionally, IFC-MP maintains relatively stable performance under varying compliance levels. Overall, the IFC-MP is an effective method for alleviating congestion on port motorways, excelling in optimizing both traffic efficiency and pollutant emissions.

A Comparative Study of Deep Reinforcement Learning Algorithms for Urban Autonomous Driving: Addressing the Geographic and Regulatory Challenges in CARLA

2025-06-17

Yechan Park , Woomin Jun , Sungjin Lee | Applied Sciences

To enable autonomous driving in real-world environments that involve a diverse range of geographic variations and complex traffic regulations, it is essential to investigate Deep Reinforcement Learning (DRL) algorithms capable … To enable autonomous driving in real-world environments that involve a diverse range of geographic variations and complex traffic regulations, it is essential to investigate Deep Reinforcement Learning (DRL) algorithms capable of policy learning in high-dimensional environments characterized by intricate state–action interactions. In particular, closed-loop experiments, which involve continuous interaction between an agent and their driving environment, serve as a critical framework for improving the practical applicability of DRL algorithms in autonomous driving systems. This study empirically analyzes the capabilities of several representative DRL algorithms—namely DDPG, SAC, TD3, PPO, TQC, and CrossQ—in handling various urban driving scenarios using the CARLA simulator within a closed-loop framework. To evaluate the adaptability of each algorithm to geographical variability and complex traffic laws, scenario-specific reward and penalty functions were carefully designed and incorporated. For a comprehensive performance assessment of the DRL algorithms, we defined several driving performance metrics, including Route Completion, Centerline Deviation Mean, Episode Reward Mean, and Success Rate, which collectively reflect the quality of the driving in terms of its completeness, stability, efficiency, and comfort. Experimental results demonstrate that TQC and SAC, both of which adopt off-policy learning and stochastic policies, achieve superior sample efficiency and learning performances. Notably, the presence of geographically variant features—such as traffic lights, intersections, and roundabouts—and their associated traffic rules within a given town pose significant challenges to driving performance, particularly in terms of Route Completion, Success Rate, and lane-keeping stability. In these challenging scenarios, the TQC algorithm achieved a Route Completion rate of 0.91, substantially outperforming the 0.23 rate observed with DDPG. This performance gap highlights the advantage of approaches like TQC and SAC, which address Q-value overestimation through statistical methods, in improving the robustness and effectiveness of autonomous driving in diverse urban environments.

Distributed Trajectory Optimization for Connected and Automated Vehicle Platoons Considering Safe Inter-Vehicle Following Gaps

2025-06-17

Meiqi Liu , Ying Gao , Yikai Zeng +1 more | Systems

Existing studies on platoon trajectory optimization of connected and automated vehicles face challenges in balancing computational efficiency, privacy, and safety. This study proposes a distributed optimization method that decomposes the … Existing studies on platoon trajectory optimization of connected and automated vehicles face challenges in balancing computational efficiency, privacy, and safety. This study proposes a distributed optimization method that decomposes the platoon trajectory planning problem into independent individual vehicle tasks while ensuring safe inter-vehicle following gaps and maximizing travel efficiencyand ride comfort. The individual vehicle problems independently optimize their trajectory to improve computational efficiency, and only exchange dual variables related to safe following gaps to preserve privacy. Simulation experiments were conducted under single-platoon scenarios with different simulation horizons, as well as multi-platoon and platoon-merging scenarios, to analyze the control performance of the distributed method in contrast to the centralized method. Simulation results demonstrate that the mean computation time is reduced by 50% and the fuel consumption is decreased by 4% compared to the centralized method while effectively maintaining the safe inter-vehicle following gaps. The distributed method shows its scalability and adaptability for large-scale problems.

MOBIL-based traffic prediction and interaction-aware Model Predictive Control for autonomous highway driving

2025-06-17

X. Zhang , Sahar Zeinali , Haowei Wen +1 more | Control Engineering Practice

Distributed modeling and hybrid triggered coordination: A modular synthesis of X-by-wire actuators for high performance vehicular control

2025-06-17

Hongye Lv , Fankai Zhou , Chen Tang +2 more | Control Engineering Practice

A microscopic derivation of a traffic flow model on a junction with two entry lines

2025-06-17

Pierre Cardaliaguet | ESAIM. Mathematical modelling and numerical analysis

We derive a conservation law on a network made of two incoming branches and a single outgoing one from a discrete traffic flow model. The continuous model is obtained from … We derive a conservation law on a network made of two incoming branches and a single outgoing one from a discrete traffic flow model. The continuous model is obtained from the discrete one by letting the number of vehicles tend to infinity and after scaling. In the discrete model, the vehicles solve a follow-the-leader model on each branch. The priority rule at the junction is given by a time-periodic traffic light (with a period tending to infinity with the scaling for technical reasons). The conservation law at the limit is $L^1-$contractive and described in terms of a germ depending on the flux and on the average amount of time the traffic light is ``green'' on a branch.

Analysis of the Impact for Mixed Traffic Flow Based on the Time-Varying Model Predictive Control

2025-06-17

Rongjun Cheng , Haoli Lou , Qi Wei | Systems

The connected and automated vehicles (CAV) smoothing mixed traffic flow has gained attention, and a thorough assessment of these control algorithms is necessary. Our previous research proposed the time-varying model … The connected and automated vehicles (CAV) smoothing mixed traffic flow has gained attention, and a thorough assessment of these control algorithms is necessary. Our previous research proposed the time-varying model predictive control (TV-MPC) strategy, which considers the time-varying driving style of human driven vehicles (HDV), performing better than current baseline models. Due TV-MPC can be applied to any traffic congestion scenario and the dynamic modeling that considers driving style, can be easily transferred to other control algorithms. Thus, TV-MPC enable to represent typical control algorithms in mixed traffic flow. This study investigates the performance of TV-MPC under diverse disturbance characteristics and mixed platoons. Firstly, quantifying mixed traffic flow with different CAV penetration rates and platooning intensities by a Markov chain model. Secondly, by constructing evaluation indicators for micro-level operation of mixed traffic flow, this paper analyzed the impact of TV-MPC on the operation of mixed traffic flow through simulation. The results demonstrate that (1) CAV achieve optimal control at specific positions within mixed traffic flow; (2) higher CAV penetration enhances TV-MPC performance; (3) dispersed CAV distributions improve control effectiveness; and (4) TV-MPC excels in scenarios with significant disturbances.

Dynamic Weight Model Predictive Control for Longitudinal Adaptive Cruise Systems in Electric Vehicles

2025-06-16

Wentian Wei , Lan Li , Qiyuan Li +3 more | Applied Sciences

This paper proposes a dynamic weight model predictive control (DWMPC) strategy for adaptive cruise control (ACC) in pure electric vehicles, aiming to enhance robustness, energy efficiency, and ride comfort under … This paper proposes a dynamic weight model predictive control (DWMPC) strategy for adaptive cruise control (ACC) in pure electric vehicles, aiming to enhance robustness, energy efficiency, and ride comfort under complex traffic conditions. Unlike conventional MPC with static weights, the proposed method integrates a fuzzy inference system that evaluates driving urgency based on real-time spacing and velocity errors. The resulting emergency coefficient is mapped through a nonlinear function to dynamically adjust the velocity tracking weight in the MPC cost function. Additionally, a four-mode coordination mechanism adaptively modifies acceleration and jerk penalties according to risk levels, enabling balanced responses between safety and comfort. A composite performance evaluation index (PEI) is formulated to quantitatively assess energy consumption, ride comfort, spacing accuracy, and emergency responsiveness. Simulation results under WLTC and typical urban driving scenarios demonstrate that DWMPC outperforms fixed-weight MPC and PI controllers, reducing energy consumption by 6.5%, jerk by 42.9%, and response time by 41.8% while improving coordination in speed tracking, inter-vehicle distance regulation, and energy-efficient control.

Evaluating the Impact of AV Penetration and Behavior on Freeway Traffic Efficiency and Safety Using Microscopic Simulation

2025-06-16

Tae-Dok Eom , Minju Park | Sustainability

As autonomous vehicles (AVs) are gradually integrated into existing traffic systems, understanding their impact on freeway operations becomes essential for effective infrastructure planning and policy design. This study explores how … As autonomous vehicles (AVs) are gradually integrated into existing traffic systems, understanding their impact on freeway operations becomes essential for effective infrastructure planning and policy design. This study explores how AV penetration rates, behavior profiles, and freeway geometry interact to influence traffic performance and safety. Using microscopic simulations in VISSIM (a high-fidelity traffic simulation tool), four typical freeway segment types—basic sections, weaving zones, on-ramp merging areas, and AV-exclusive lanes—were modeled under diverse traffic demands and AV behavior settings. The findings indicate that, while AVs can improve flow stability in simple environments, their performance may deteriorate in complex merging scenarios without supportive design or behavior coordination. AV-exclusive lanes offer some mitigation when AV share is high. These results underscore that AV integration requires context-specific strategies and cannot be universally applied. Adaptive, behavior-aware traffic management is recommended to support a smooth transition toward mixed autonomy.

Non-Conventional Lane Design and Control Coordination Optimization at Urban Road Intersections: Review and Prospects

2025-06-16

Yizhe Wang , Xiaoguang Yang | Applied Sciences

Optimally configuring the number and turning functions of intersection approach and exit lanes to adapt to changing traffic demands, along with optimal traffic signal timing, is key to ensuring smooth, … Optimally configuring the number and turning functions of intersection approach and exit lanes to adapt to changing traffic demands, along with optimal traffic signal timing, is key to ensuring smooth, safe, and efficient urban road intersections. Compared to conventional “left-straight-right” lane configurations, non-conventional lanes have been widely adopted by various countries in recent years. This paper systematically reviews research progress on non-conventional lane design and control coordination optimization at urban road intersections, including operational mechanisms, applicable conditions, and optimization methods for various forms. By examining relevant research findings, the paper analyzes the effectiveness of non-conventional lanes in improving capacity, reducing delays, and enhancing safety. The research finds that although the application of non-conventional lanes has achieved positive results in practice, issues still exist, such as “practice outpacing theory,” “insufficient utilization of time-space resources,” and “incomplete safety evaluation.” Future research should focus on constructing a systematic evaluation framework, establishing demand-responsive dynamic lane function conversion mechanisms, developing refined and precise control methods with spatiotemporal coordination, and further exploring innovative applications of non-conventional lanes in connected and automated vehicle environments. The findings will provide theoretical and technical support for the scientific design and efficient operation of non-conventional lanes at urban road intersections.

Scaling methods for estimating macroscopic fundamental diagrams in urban networks with sparse stationary sensor coverage

2025-06-16

Nandan Maiti , Manon Seppecher , Ludovic Leclercq | Transportation Research Part C Emerging Technologies

Leveraging probabilistic inference for robust calibration of microscopic traffic models

2025-06-15

Mehdi Rafati Fard | International Journal of Modelling and Simulation

A lattice model of mixed traffic flow based on critical safety potential field and driver vigilance feedback: Numerical simulation of critical safety potential field fluctuations characterizing the effects of vehicle mass and volume differences

2025-06-13

Hongzhuan Zhao , Yijie Tang , Yichen Wang +7 more | Chaos Solitons & Fractals

A simple methodology for evaluating the robustness of decentralised traffic signal controllers

2025-06-13

Namrata Gupta , Gopal R. Patil , Hai L. Vu | Transportmetrica B Transport Dynamics

CAV-dedicated lane sharing strategy of expressway in mixed traffic environment: A novel dynamic lane-level tolling method

2025-06-12

Weihua Zhang , Haiyang Zhang , Hanyi Ding +3 more | Transportation Research Part A Policy and Practice

C2TE: Coordinated constrained task execution design for ordering-flexible multi-vehicle platoon merging

2025-06-12

Bin-Bin Hu , Yanxin Zhou , Henglai Wei +2 more | Automatica

Driving behavior performance from tunnel main road to underground merging area: A real vehicle study based on speed and lateral offset

2025-06-12

Fangtong Jiao , Peipei Guo , Zhigang Du +3 more | Traffic Injury Prevention

Multi-entry underpass road tunnels feature long entrance downhill sections and underground merging areas where main and secondary roads converge. These complex driving environments can lead to variations in driver speed … Multi-entry underpass road tunnels feature long entrance downhill sections and underground merging areas where main and secondary roads converge. These complex driving environments can lead to variations in driver speed and lateral offset, increasing the risk of traffic accidents. Therefore, this study aims to analyze the speed and lateral offset characteristics in different tunnel sections and their impact on traffic safety, providing support for traffic control and safety improvements in multi-entry underpass tunnels. This study conducted real-vehicle natural driving tests using test vehicles equipped with an inertial navigation system and Mobileye. Based on changes in tunnel alignment and road parameters, the study divided the test sections into five segments: tunnel external section, entrance downhill section, entrance internal section, underground merging section, and tunnel internal section. By analyzing the speed variation trends, lateral offset characteristics, and their interrelationships across these sections, a standardized relative deviation fraction was introduced to quantitatively compare driving behavior in key sections, revealing differences in driving patterns and potential safety risks across different road segments. The speed growth rate in the entrance downhill section was the highest at 15.09%. In contrast, drivers in the underground merging section had the lowest average speed at 54.057 km/h and the highest speed dispersion. The underground merging section had the lowest rate of lateral offset change but the highest dispersion in lane offset within this section. Conversely, the entrance downhill section showed the smallest dispersion, with a standard deviation of only 0.111. In addition, research found that the driving distance in each road section is positively correlated with vehicle speed and negatively correlated with lane offset. Through real-vehicle tests, this study analyzed the speed, lateral offset, and driving safety characteristics of different sections in multi-entry tunnels. The results indicate that the entrance downhill section and underground merging section pose higher driving risks, as fluctuations in speed and lateral offset contribute to driving instability. These findings reveal the driving risks associated with specific sections of multi-entry underpass road tunnels and provide important references for tunnel traffic management and safety optimization.

Discontinuous Galerkin method with Godunov-like numerical fluxes for traffic flows on networks. Part II: Maximum principle

2025-06-12

Lukáš Vacek , Chi‐Wang Shu , Václav Kučera | Applications of Mathematics

Integrating micro and macro traffic control for mixed autonomy traffic

2025-06-10

Tingting Fan , Jieming Chen , Edward Chung | Communications in Transportation Research

Investigation of the Impact of Intersection Designs, Signalization, and Directions of Intersection Arms on Microscopic Networks: The Case of Erzurum Province

2025-06-10

Zühal Zirek , Muhammed Ali Çolak | Sakarya University Journal of Science

Transportation has an important connection in many aspects such as economic growth, trade, tourism and social interaction. Today, the demand for transportation services is increasing with the rapid socio-economic development. … Transportation has an important connection in many aspects such as economic growth, trade, tourism and social interaction. Today, the demand for transportation services is increasing with the rapid socio-economic development. This increase brings with it various traffic problems. Effective intersection design in preventing congestion, delays and accidents is of great importance in terms of ensuring traffic safety and sustainability. In this study, Gürcükapı Intersection and Taşhan Intersection were remodeled with Aimsun software in order to reduce the density at the intersections in Erzurum province and to meet traffic needs. Signalization was added to the modeled intersections, the directions of the intersection arms were changed and four alternative scenarios were created with these changes using current scenario. A total of five scenarios, including the current scenario and the developed alternatives, were evaluated and compared based on travel time, delay time, waiting time, speed, queuing, instant CO2, NOx, PM (Particulate Matter) and VOC (Volatile Organic Compounds) values. As a result of the comparison, the scenario in which the current intersection arm direction and Gürcükapı and Taşhan intersections are modernized and there is no signaling system was determined as the most effective scenario.