Microscopic Simulation

To increase operational efficiency, resilience and capacity of the railway system, the development of modern railway traffic management system (TMS) has attracted more and more attention in recent years. To support the development and implementation of the next generation of TMS and related applications, advanced data collection, transmission and processing approaches, digitalised databases, and virtual validation platforms, etc., are required. In the context of the TMS development (addressed by Technology Demonstrator 2.9 of Shift2Rail Innovation Programme 2), this support is to be provided by a scalable, interoperable and standardised communication platform for internal and external communication between different subsystems, applications and clients. This paper outlines the approach of the ongoing OPTIMA project aimed to develop a communication platform demonstrator for railway TMS based on a novel Integration Layer (IL) and its various interfaces to entities including integration layer services, TMS service, rail business service, external services and operator workstations. Further detailed discussion in this paper relates to the approach to validating the communication platform demonstrator as a functional entity, and as a virtual testing environment to validate railway traffic management and other applications. The validation approach for the applications tested on the communication platform demonstrator is also presented. The results of future implementation of this validation approach will be used to assess the functionality of the communications platform demonstrator developed, and the initial TMS applications tested on it, and form an important step towards developing and implementing IL based communications platforms for future TMSs.

This study will analyse the effect the road traffic and travel situation is highly aggravated in metropolitan cities of developing country like India because of significant growth in traffic and addition of more and more numbers of vehicles year by year in to the stream with wide ranging static and dynamic characteristics. Signalisation is a traffic control strategy to ease the competition by providing right of way in a cyclic manner to conflicting traffic at intersections. Saturation flow is a major component in the design of signals, and is influenced by a variety of factors like vehicle composition, intersection geometry and driver's behaviour. Two-wheelers (2W) constitute a major proportion of urban traffic and therefore their effect on the saturation flow could be substantial. The highway capacity manual (HCM) has recommended a saturation flow model primarily for homogeneous conditions, with limited ability to address heterogeneity. But the traffic in India is highly heterogeneous and hence, defining a unified saturation flow concept is a challenging task. The variability in vehicle types necessitates the use of passenger car units (PCUs).Mixed traffic behaviour on saturation flow rate at the signalised intersections. Traffic data will be collected at signalised intersections located in urban area of different cities of Gujarat with different geometric configurations and approach width. Micro level discharge rate studies will be carried out by observing different traffic attributes. The passenger car units (PCUs) values will be derived for different types of vehicles in the traffic stream by different approaches. Mixed traffic discharge flow models will be developed using regression method by relating the various parameters. Also an effect of platoon dispersion on discharge rate will be carried out under this study.

This study will analyse the effect the road traffic and travel situation is highly aggravated in metropolitan cities of developing country like India because of significant growth in traffic and addition of more and more numbers of vehicles year by year in to the stream with wide ranging static and dynamic characteristics. Signalisation is a traffic control strategy to ease the competition by providing right of way in a cyclic manner to conflicting traffic at intersections. Saturation flow is a major component in the design of signals, and is influenced by a variety of factors like vehicle composition, intersection geometry and driver's behaviour. Two-wheelers (2W) constitute a major proportion of urban traffic and therefore their effect on the saturation flow could be substantial. The highway capacity manual (HCM) has recommended a saturation flow model primarily for homogeneous conditions, with limited ability to address heterogeneity. But the traffic in India is highly hetero...

This study will analyse the effect the road traffic and travel situation is highly aggravated in metropolitan cities of developing country like India because of significant growth in traffic and addition of more and more numbers of vehicles year by year in to the stream with wide ranging static and dynamic characteristics. Signalisation is a traffic control strategy to ease the competition by providing right of way in a cyclic manner to conflicting traffic at intersections. Saturation flow is a major component in the design of signals, and is influenced by a variety of factors like vehicle composition, intersection geometry and driver's behaviour. Two-wheelers (2W) constitute a major proportion of urban traffic and therefore their effect on the saturation flow could be substantial. The highway capacity manual (HCM) has recommended a saturation flow model primarily for homogeneous conditions, with limited ability to address heterogeneity. But the traffic in India is highly heterogeneous and hence, defining a unified saturation flow concept is a challenging task. The variability in vehicle types necessitates the use of passenger car units (PCUs).Mixed traffic behaviour on saturation flow rate at the signalised intersections. Traffic data will be collected at signalised intersections located in urban area of different cities of Gujarat with different geometric configurations and approach width. Micro level discharge rate studies will be carried out by observing different traffic attributes. The passenger car units (PCUs) values will be derived for different types of vehicles in the traffic stream by different approaches. Mixed traffic discharge flow models will be developed using regression method by relating the various parameters. Also an effect of platoon dispersion on discharge rate will be carried out under this study.

Deceleration characteristics of vehicles are important for intersection design, deceleration lane design, traffic simulation modeling, vehicular emission and fuel consumption modeling, etc. Heterogeneous traffic stream consists of vehicles with wide variation in their physical dimensions, weight to power ratio and dynamic characteristics, which affect their deceleration behaviour. Majority of past studies are restricted to deceleration behaviour study of cars and trucks in homogenous traffic. Present study aims to analyze the deceleration behaviour of different vehicles types (like truck, car, motorized two and three-wheeler) on Nagpur-Mumbai Express Highway at Wardha, India. Drivers were asked to decelerate their vehicles from their maximum speed to zero speed in shortest time and their speed profiles are collected using Global Positioning System. Deceleration behaviour of different vehicle types is significantly different. Vehicles with higher maximum speed have higher deceleration time, deceleration distance, maximum and mean deceleration rates during their deceleration manoeuvre. In deceleration manoeuvre, vehicle's deceleration rate initially increases, attains the maximum deceleration and decreases afterwards. A dual regime model is developed to describe deceleration behaviour over entire speed range of all vehicle types except car. For car, a second order polynomial is proposed.

This paper describes the state of advancement achieved in the OptiYard research project in the use of optimisation algorithms in interaction with microsimulation of the rail-yard and surrounding network towards real-time yard management and communication with the network. Two case studies, a hump marshalling yard (mainly Single Wagon Load traffic) and a flat shunting yard (mainly intermodal traffic), were represented with state-of-the art microsimulation models, combined with innovative optimisation algorithms. Some specialistic information on the nature of the models is provided. However, the focus is oriented to railway engineers, with a description of the interactions between the models in producing outputs that are useful both to the yard dispatcher (decisions on staff, track, locomotive assignment, order of operations) and the infrastructure manager of the surrounding network (expected times of departure, availability of tracks in the yard)

Over the years the characteristics of traffic on Dutch motorways has changed, but its design guidelines did not develop as rapidly and large parts remain unchanged since the first guidelines from the 1970s. During the latest revision of the Dutch motorway design guidelines it became clear that a solid and comprehensive theoretical, or evidence based, background was lacking for the validity of the prescribed ramp spacing and required length for weaving segments. This article presents the underpinning of revising the Dutch design manual for motorways for turbulence in traffic. For this study loop detector data at eight on-ramps and five off-ramps were collected as well as empirical trajectory data at fourteen different on-ramps (three), off-ramps (three) and weaving segments (eight) in The Netherlands. The results show that the areas around ramps that are influenced by turbulence are smaller than described in the design manuals and that, in their present form, the microscopic simulation software packages VISSIM and MOTUS fail to simulate the number and location of lane-changes around ramps realistically.

h i g h l i g h t s An automated VISSIM calibration tool, VISCAL, is developed supporting three heuristic optimization algorithms. VISCAL can test the significance of the appropriate decision parameter set for a particular network. VISCAL can determine the most suitable objective function to reflect network characteristics. VISCAL can check the suitability of any of the three heuristic optimization algorithms for a particular network. Combination of multi-objective criteria and GA provides the best estimation for speed and flow in the freeway scenario.

Safe driving can be achieved by prevention of risky situations which requires the knowledge of the vehicle dynamics and road geometry. The Indian traffic condition is heterogeneous in nature and has weak lane discipline. Hence, vehicles interactions takes place laterally also along with their longitudinal interaction. Vehicles lateral movements (interactions) are quite high due to absence of lane discipline. Therefore, the lateral acceleration of vehicles are an important variable which characterizes the corresponding vehicle dynamics. Several studies have been done by various authors on lateral acceleration in curves, however, lateral movement study of vehicles on straight road section is also important to analyze vehicles’ maneuver in such traffic (i.e. traffic stream with weak lane discipline). Therefore, the present study is about the observation of lateral movements of vehicles over different types of roads in three metropolitan cities of India (Kolkata, Mumbai and Pune) under ...

During the peak hour, drivers are occasionally allowed to use the shoulder lane on the Kanjanapisek Expressway to provide additional space and reduce travel delay. Based on the observation, we found a significant number of vehicles regularly used the shoulder lane both during the peak and off-peak period. Concentrate on midblock section, we found the use of shoulder lane during the free flow traffic condition. The consequence of inconsistent lane utilization on midblock section affects the stability of traffic flow and creates a bottleneck on the expressway. This study aimed to investigate the characteristic of shoulder lane utilization behavior, identified significant parameters affecting shoulder lane utilization behavior and compared the empirical data with simple linear regression and sigmoid function. In this study, the empirical data of 5 expressway midblock sections on the Kanjanapisek Expressway was chosen for study area. Traffic stream data collections were gathered from im...

In this letter, we detail a modular approach for measuring the secondary physical and emotional effects of ambient intelligence (AmI) technology in traffic. Using the case of merges on to a highway, we assess the results of a system that advises the driver to change early to a lane on the left to create space for merging cars downstream (tested using a cellular automata simulation). The indirect impact of the system downstream, namely how the remaining lane changes from the merge lane to the innermost lane proceed, is then evaluated using a time-discrete, space-continuous microscopic traffic simulation tool. This yields detailed results concerning driver interactions that can also be used to derive an estimate of driver anger in the situation. We have used real geographic, traffic and psychological data to test the system, and different models are used to accomplish various tasks. The approach yields (surprisingly) negative results concerning the indirect emotional impact of this AmI intervention which may be due to the nature of the lane changing model used and the chosen parameters. We argue that such an approach is also applicable to similar types of systems, where different data and model types are suited to different scenario elements.

The car following behaviour of a driver is the process of following the drivers to create an adjustment in the leading vehicle behaviour. In a condition, where the traffic volume is in a free-flowing situation, the selection of vehicles speed is typically limited by some factors such as weather conditions, lighting, and road geometry features. This study aims to investigate the effects of climates on driver’s car following behaviour and speed flow relationships for highways in Kuwait. The case study was conducted at Road 40 in Kuwait using RTMS Sx-300 device which is known as a radar device particularly used for monitoring traffic. The data was gathered between the periods from 29th December 2018 to 5th January 2019 within winter. MATLAB code was written to analyse and classify the gathered data. Then, the models were built using R-software. The study depicts that nearly 24.87% of the vehicles move between 60 km/h and 69 km/hour. Additionally, the vehicles were segmented according t...

Modeling effective vehicular traffic is a highly contested topic, especially in developing countries like Sri Lanka, which has a wide range of driving conditions. VISSIM microsimulation software is currently used by Road Development Authority (RDA) and relevant authorities to perform traffic management solutions in Sri Lanka. However, it is required to do modifications to the existing driver behavior parameter values to effectively reflect the realistic traffic conditions observed in the real-world in the simulated model. The main purpose of this study is to calibrate the VISSIM driver behavior parameter values using a genetic algorithm (GA). The methodology and results of the VISSIM model’s sensitivity analysis and calibration, which was developed for the Malabe three-legged signalized intersection, are presented in this study. A sensitivity analysis was used to find the most sensitive driver behavior parameters. Using the multi-objective GA optimization tool in the MATLAB software...

Sodoben življenjski slog zahteva visoko stopnjo mobilnosti, ki se odraža v povečanih prometnih obremenitvah. Na nekaterih najbolj obremenjenih avtocestnih odsekih dnevno prihaja do zastojev, kar daje vodenju prometačedalje izrazitejšo vlogo. Zaradi velikih zgostitev prometa se v okolici ozkih grlpojavljajo udarni valovi, ki običajno potujejo protitočno in povzročajo nenadna povečanja gostote prometnega toka ter posledično nenadna zmanjšanja srednje prostorske hitrosti prometnega toka.Udarni valovi povzročajo negativne ekološke in ekonomske vplive, z njimi povezani zastoji pa tudi potencialno nevarnost za prometne nesreče, predvsem v obliki naletnih trčenj. Namen doktorske disertacije jepredlagati učinkovitejše vodenje prometnega tokas spremenljivimi omejitvami hitrosti, ki temelji na zmanjšanju intenzivnosti in pogostosti pojavljanja udarnih valov. Najprej smo kontinuitetne makroskopske modele prometnega tokaovrednotili in izbrali najustreznejšega glede na kvalitativno sposobnost op...

Indian traffic can be considered as chaotic, with various types of vehicles present with no lane discipline. In order to model Indian traffic condition, it is necessary to incorporate both the v conditions in a meaningful way. Research has been made on weak lane discipline or vehicular heterogeneity as a single entity, but both these criteria are not present in a single model. In the present study, an attempt is made to quantify the unaccounted parameters of heterogeneity for Indian traffic into the existing car-following models to form a modified car-following model. A simulation model has been developed as a software program to study the performance of the modified car-following model in replicating Indian conditions. This model is used to simulate the traffic stream and some preliminary results are obtained. They are validated with field data collected from a major road in Delhi. The model is able to satisfactorily simulate the realtime traffic conditions. Analysis is carried out for roadway traffic characteristics, distribution of vehicles along roadway width and speed distribution of vehicles. The model, after extensive validation at a later stage, can be useful for future traffic experts for application.

Modeling effective vehicular traffic is a highly contested topic, especially in developing countries like Sri Lanka, which has a wide range of driving conditions. VISSIM microsimulation software is currently used by Road Development Authority (RDA) and relevant authorities to perform traffic management solutions in Sri Lanka. However, it is required to do modifications to the existing driver behavior parameter values to effectively reflect the realistic traffic conditions observed in the real-world in the simulated model. The main purpose of this study is to calibrate the VISSIM driver behavior parameter values using a genetic algorithm (GA). The methodology and results of the VISSIM model’s sensitivity analysis and calibration, which was developed for the Malabe three-legged signalized intersection, are presented in this study. A sensitivity analysis was used to find the most sensitive driver behavior parameters. Using the multi-objective GA optimization tool in the MATLAB software...

Traffic microsimulation is increasingly a preferred method of traffic analysis for today's transportation professionals. The importance of properly calibrating these traffic simulations is evidenced by the adoption of microsimulation calibration standards by several state and federal transportation authorities. A component of the calibration process is the calibration of the simulation for capacity. Capacity is a high-level measurement that is a function of many lowerlevel user-defined input parameters. VISSIM utilizes psychophysical car-following models that rely on ten userdefined parameters to represent freeway driving behavior. Several VISSIM driver behavior parameters have been shown to have a significant impact on roadway capacity. This paper seeks further understanding of the performance of the VISSIM traffic microsimulator by investigating the impact of driver behavior parameter combinations on a measure of freeway capacity. This paper is intended to provide insight useful for manual calibration of VISSIM microsimulation or the development of calibration algorithms.

Traditionally, road safety analysis has been conducted by analysing collision records, which has a reactive approach as the analyst waits for collisions to occur. The alternate proactive approach in the form of surrogate safety measures is to study traffic conflicts which are bound to occur more frequently and thus has related them to the possible incidences of collisions. In the present study, traffic conflict indicators have been used to assess the level of safety by considering the typical midblock sections of an interurban corridor using vehicle trajectory data extracted through microscopic simulation. The surrogate safety parameters such as Time to Collision (TTC), Deceleration Rate (DR), change in velocity (Delta V) as well as conflicting vehicle Speed (Max S) have been extracted from trajectory data throughthe application of numerical elaboration to evaluate safety. Further, an attempt has been made to quantify the traffic conflicts occurring at the midblock of referred study. The proposed threshold values of surrogate safety parameters have been validated using the reported three years' crash data. The approach presented in the paper has helped in the identification of midblock locations prone to road crashes and hence has served as a proactive alternative as opposed to historical crash based analysis.

The car following behaviour of a driver is the process of following the drivers to create an adjustment in the leading vehicle behaviour. In a condition, where the traffic volume is in a free-flowing situation, the selection of vehicles speed is typically limited by some factors such as weather conditions, lighting, and road geometry features. This study aims to investigate the effects of climates on driver’s car following behaviour and speed flow relationships for highways in Kuwait. The case study was conducted at Road 40 in Kuwait using RTMS Sx-300 device which is known as a radar device particularly used for monitoring traffic. The data was gathered between the periods from 29th December 2018 to 5th January 2019 within winter. MATLAB code was written to analyse and classify the gathered data. Then, the models were built using R-software. The study depicts that nearly 24.87% of the vehicles move between 60 km/h and 69 km/hour. Additionally, the vehicles were segmented according t...

Car-following models are used in microscopic simulation tools to calculate the longitudinal acceleration of a vehicle based on the speed and position of a leading vehicle in the same lane. Bicycle traffic is usually included in microscopic traffic simulations by adjusting and calibrating behavior models developed for motor vehicle traffic. However, very little work has been carried out to examine the following behavior of bicyclists, calibrate following models to fit this observed behavior, and determine the validity of these calibrated models. In this paper, microscopic trajectory data collected in a bicycle simulator study are used to estimate the following parameters of the psycho-physical Wiedemann 99 car-following model implemented in PTV Vissim. The Wiedemann 99 model is selected due to the larger number of assessable parameters and the greater possibility to calibrate the model to fit observed behavior. The calibrated model is validated using the indicator average queue dissi...

The use of microscopic traffic simulation models in traffic operations, transportation design, and transportation planning has become widespread across the United States because of: (i) rapidly increasing computer power; (ii) the development of sophisticated traffic micro-simulation tools; and (iii) the need by transportation engineers to solve complex problems which do not lend themselves to traditional analysis techniques. This paper presents an application of traffic microsimulation to the analysis of actuated advance warning (AAW) system operations at high-speed signalized intersections. It has been shown that there is a-greater-than 90% likelihood that the installation of an AAW system - consisting of one detector in advance of the intersection and active warning signs with the legend "PREPARE TO STOP WHEN FLASHING" - at a high-speed signalized intersection, enhances traffic safety (1) . Microscopic traffic simulation modeling is an ideal tool for the analyses of inte...

During the peak hour, drivers are occasionally allowed to use the shoulder lane on the Kanjanapisek Expressway to provide additional space and reduce travel delay. Based on the observation, we found a significant number of vehicles regularly used the shoulder lane both during the peak and off-peak period. Concentrate on midblock section, we found the use of shoulder lane during the free flow traffic condition. The consequence of inconsistent lane utilization on midblock section affects the stability of traffic flow and creates a bottleneck on the expressway. This study aimed to investigate the characteristic of shoulder lane utilization behavior, identified significant parameters affecting shoulder lane utilization behavior and compared the empirical data with simple linear regression and sigmoid function. In this study, the empirical data of 5 expressway midblock sections on the Kanjanapisek Expressway was chosen for study area. Traffic stream data collections were gathered from im...

As the world population and the traffic demand are constantly inflating, there is a substantial need to procure a safe and effective method for traffic control and management. Thus, traffic signals operate to manage the flow of vehicles and vulnerable road users through intersections. Intelligent Transport Systems (ITS) technologies based on vehicle connectivity and information exchange may overcome the cons of fixed‐time traffic signals in coping with the unplanned traffic stream. The roadmap for operating connected vehicles in an urban environment is still in the planning phase and in order to achieve sustainable results, a proper management technique must control the flow of vehicles. Green Light Optimal Speed Advisory (GLOSA) utilizes infrastructure and vehicles communication through using current signal plan settings and updated vehicular information in order to influence the intersection approach speeds. This thesis presents a traffic microsimulation study that investigates th...

In this paper, we first review a localized ramp-metering strategy for freeways that achieves the goal of reducing the spatial and temporal span of traffic congestion, using locally available information. The control scheme is composed of a switching mainline-traffic responsive ramp-metering controller that adapts to the different traffic dynamics under different congestion conditions-free-flow or congested-and a queue length regulator that yields improved performance over the currently used ad hoc "queueoverride" scheme and prevents the queue from exceeding the ramp storage capacity. Subsequently, a queue length estimator is designed to provide feedback to the queue length regulator, using the queue-detector speed data that are available in the field. Test results on a calibrated microscopic traffic simulator demonstrate the performance and effectiveness of the switching ramp-metering controller, the queue length estimator and regulator, and the overall control strategy. The Total Vehicle and Passenger Delays are both reduced by 16%, while the Total Vehicle Time and the Total Average Vehicle Speed are improved by 5.6% and 5.8%, respectively. As a comparison, simulation results of ALINEA are also presented.

Many pieces of research have concentrated on traffic speed, time headway, space headway, and so on under non-lane-based heterogeneous traffic streams. In contrast, limited studies have been conducted for analyzing and modeling the vehicular lateral position. The lateral position of vehicles plays an equally vital role in the development of microscopic models. Moreover, the vehicle characteristics such as the lateral position and speed are considered independent in the traffic simulation modeling, ignoring their correlation. This study investigates the relationship between the lateral position of vehicles with traffic speed on rural highways. For this purpose, the traffic data related to different vehicles' lateral positions and speed were collected using an infrared sensor instrument from the National Highways in India. The relationship of vehicles' lateral position with the traffic speeds under different ranges is analyzed to understand their dependence. The study results show that the relationship between vehicles' lateral position is significantly associated with the traffic speed. The study findings help formulate a microscopic simulation model to reproduce accurate maneuvering in the traffic stream, which is useful for analyzing traffic characteristics.

In this letter, we detail a modular approach for measuring the secondary physical and emotional effects of ambient intelligence (AmI) technology in traffic. Using the case of merges on to a highway, we assess the results of a system that advises the driver to change early to a lane on the left to create space for merging cars downstream (tested using a cellular automata simulation). The indirect impact of the system downstream, namely how the remaining lane changes from the merge lane to the innermost lane proceed, is then evaluated using a time-discrete, space-continuous microscopic traffic simulation tool. This yields detailed results concerning driver interactions that can also be used to derive an estimate of driver anger in the situation. We have used real geographic, traffic and psychological data to test the system, and different models are used to accomplish various tasks. The approach yields (surprisingly) negative results concerning the indirect emotional impact of this AmI intervention which may be due to the nature of the lane changing model used and the chosen parameters. We argue that such an approach is also applicable to similar types of systems, where different data and model types are suited to different scenario elements.

In urban areas, interchange spacing and the adequacy of design for weaving, merge, and diverge areas can significantly influence available capacity. Traffic microsimulation tools allow detailed analyses of these critical areas in complex locations that often yield results that differ from the generalized approach of the Highway Capacity Manual. In order to obtain valid results, various inputs should be calibrated to local conditions. This project investigated basic calibration factors for the simulation of traffic conditions within an urban freeway merge/diverge environment. By collecting and analyzing urban freeway traffic data from multiple sources, specific Iowa-based calibration factors for use in VISSIM were developed. In particular, a repeatable methodology for collecting standstill distance and headway/time gap data on urban freeways was applied to locations throughout the state of Iowa. This collection process relies on the manual processing of video for standstill distances...

In urban areas, interchange spacing and the adequacy of design for weaving, merge, and diverge areas can significantly influence available capacity. Traffic microsimulation tools allow detailed analyses of these critical areas in complex locations that often yield results that differ from the generalized approach of the Highway Capacity Manual. In order to obtain valid results, various inputs should be calibrated to local conditions. This project investigated basic calibration factors for the simulation of traffic conditions within an urban freeway merge/diverge environment. By collecting and analyzing urban freeway traffic data from multiple sources, specific Iowa-based calibration factors for use in VISSIM were developed. In particular, a repeatable methodology for collecting standstill distance and headway/time gap data on urban freeways was applied to locations throughout the state of Iowa. This collection process relies on the manual processing of video for standstill distances...

In the present study, quantification of level of service for four-lane divided highway has been performed by using simulation technique. For the purpose, three operational service measures are proposed in the study namely traffic stream speed and platoon parameters like average platoon size and percentage following. The criteria or range for each measure to define particular LOS has been compared with criteria in Highway capacity manual (HCM) and reviewed literature. The significant difference in criteriawasobserved due to frequent lane change and undefined lateral behavior of the traffic on multilane highways. Sucha realistic Indian traffic scenario on multilane highway has been modeled and studied through micro-simulation tool 'PASSIM' developed by the authors. The study has been carried on particular section of uninterrupted flow facility which is designated here as 'Rurban' highway hasdistinctly identified between rural highway and urban roads in terms of prevail...

Comprehensive analysis of traffic behavior requires continuous studies to develop traffic theories explaining that behavior at the microscopic level. The study aims to develop a microsimulation program to evaluate the freeway weaving performance depending on the observed data. FWASIM represents a microscopic analysis of the freeway traffic features. It scans events periodically. The developed FWASIM involves the formulation of driver and vehicle behavior at freeway link, on-ramp, off-ramp, and combine them to produce a flexible, friendly use simulation model. Its concept is mainly depending on the car following and lane change theories. Analytical model validation was conducted based on a comparison of FWASIM output with the VISSIM output. Tests consider the important factors that may affect the traffic behavior for a given segment configuration. The obtained results show agreement between FWASIM and VISSIM outputs. Besides, the field data were used to validate FWASIM. Graphical and...

The research identifies the dynamical parameters in the area of mechanics within the base of traffic model parameters used by the Intelligent Driver Model (IDM), which are the highest acceleration parameters set by the vehicle, the desired speed parameters of the vehicle and the distance-keeping parameters of the vehicle. All this facilitates the automatic control of autonomous electric vehicles in certain vehicle groups.

Pedestrian unrestrained behaviour, sudden movements and vulnerability are elements, which can highly affect road safety, especially when interacting with motorized vehicles. Therefore, it is important to have a deep insight in pedestrian behaviour. A way to tackle this issue is micro-simulation. Modern micro-simulation tools, indeed, allow, thanks to the implemented mathematical formulation of the problem, to model and repeat a real situation in a virtual environment. Nevertheless, they need to well-fit the real observed behaviour: the calibration step allows to make the model reliable, by adapting selected, influential model input parameters. By dealing with pedestrian issues, software Vissim/Viswalk has been selected for micro-simulation, which implements Helbing's Social Force model. This model is based on several parameters, like relaxation time, side preference, strength and range of pedestrian interactions, amount of anisotropy, parameters governing the forces among pedest...

Any transport facility is essentially a service being provided to the society. Therefore, it is expected of the traffic engineers, transport planners and policy-makers alike to be able to understand and evaluate the quality of service that is being provided by the transport facilities designed by them. The level-of-service (LoS) concept was devised in the US Highway Capacity Manual (US-HCM) precisely for the above consideration. However, direct implementation of the US-HCM methods in India is not possible because of the heterogeneous traffic conditions and vastly unique driver behavior found on Indian highways. Therefore, it becomes imperative to evaluate other competing methodologies that may be more appropriate in defining the LoS being offered to the road users by Indian highways in general and multilane interurban highways in particular. Towards this end, this paper reviews in detail the LoS estimation methodologies that have been demonstrated to be suitable for application in t...

The major factor affecting road-user costs (RUC) is the speed at which vehicles operate on roads which in turn determines fuel consumption and other cost components per unit distance travelled. Thus vehicular speed plays a significant role in highway economic evaluation. In the last decade, the Government of India has been involved in road capacity augmentation by building high-speed corridors to link major cities through the implementation of National Highway Development Programme (NHDP) projects such as Golden Quadrilateral, North-South, East-West, Expressway and Port Connectivity corridors. These recent radical changes in road network coupled with enhanced vehicle technology have resulted in huge variations in speed on these highways which has made it essential to evaluate the changing speed characteristics which are important inputs in estimation of RUC. An attempt is made in this article to study the speed characteristics on high-speed multi-lane corridors in plain terrain considering both straight and curved sections spread across the country. From the collected data, free-speed profiles of different vehicle types on high-speed corridors of India are developed and subsequently free-speed equations are developed considering the effect of roadway roughness.

Mixed traffic, characterized by diverse vehicles, changing composition, lack of lane discipline, etc. is best modeled by micro simulation. However, the majority of the leading micro simulation packages and their calibration methodologies have been developed considering less complex homogeneous traffic. Hence, a methodology for calibrating a micro simulation model for mixed traffic is proposed. Driver behavior in mixed traffic is observed and adjustments were made to represent in the simulation. Calibration parameters were identified using multi parameter sensitivity analysis, and the optimum values for these parameters were obtained by minimizing the error between the simulated and field delay using a genetic algorithm. Multiple criteria were included in the optimization formulation by constraint insertion. The proposed methodology is illustrated using VISSIM, a widely used micro simulation software. Signalized intersections with different traffic characteristics from Mumbai are tak...

Mixed traffic, characterized by diverse vehicles, changing composition, lack of lane discipline, etc. is best modeled by micro simulation. However, the majority of the leading micro simulation packages and their calibration methodologies have been developed considering less complex homogeneous traffic. Hence, a methodology for calibrating a micro simulation model for mixed traffic is proposed. Driver behavior in mixed traffic is observed and adjustments were made to represent in the simulation. Calibration parameters were identified using multi parameter sensitivity analysis, and the optimum values for these parameters were obtained by minimizing the error between the simulated and field delay using a genetic algorithm. Multiple criteria were included in the optimization formulation by constraint insertion. The proposed methodology is illustrated using VISSIM, a widely used micro simulation software. Signalized intersections with different traffic characteristics from Mumbai are taken as case study.

Mixed traffic, characterized by diverse vehicles, changing composition, lack of lane discipline, etc. is best modeled by micro simulation. However, the majority of the leading micro simulation packages and their calibration methodologies have been developed considering less complex homogeneous traffic. Hence, a methodology for calibrating a micro simulation model for mixed traffic is proposed. Driver behavior in mixed traffic is observed and adjustments were made to represent in the simulation. Calibration parameters were identified using multi parameter sensitivity analysis, and the optimum values for these parameters were obtained by minimizing the error between the simulated and field delay using a genetic algorithm. Multiple criteria were included in the optimization formulation by constraint insertion. The proposed methodology is illustrated using VISSIM, a widely used micro simulation software. Signalized intersections with different traffic characteristics from Mumbai are tak...

Heavy-Duty Vehicles (HDVs) on highways are among the major passengers and freight traffic carriers that occupy any space available on the roadway. The movement of HDVs under the mixed traffic environment causes higher levels of interaction between vehicles due to their physical and operational characteristics. Besides, the HDVs operating at less than their desired speed on the highway lanes cause a mixed traffic platoon formation. The primary purpose of the study is to investigate the impact of multi-class HDVs on the speed and flow rates of each highway lane under platooning conditions. In this study, traffic data was collected using an Infra-Red (IR) sensor-based device at six highway sections in India. The simultaneous equations approach is used to model the traffic speeds for determining the Dynamic Passenger Car Unit (DPCU). The speedflow plots are established for Median Lane (ML) and Kerb Lane (KL), a minute before the arrival of HDVs (state A) and a minute after the arrival of HDVs (state B) at the IR sensor detection point, to quantify the impacts of HDVs on the speed and traffic flow rate. The study findings reveal that the speed and flow in ML and KL reduce significantly due to the influence of multi-class HDVs in the general traffic mix. Also, the speed and flow rate in ML and KL decreased with an increase in the percentage of multi-class HDVs. However, this effect was found to be comparatively higher in the ML than that in the KL. Finally, this study sets out recommendations to mitigate the adverse impacts of multi-class HDVs on the highways to enhance the speed and flow rate.

Traffic microsimulation is increasingly a preferred method of traffic analysis for today's transportation professionals. The importance of properly calibrating these traffic simulations is evidenced by the adoption of microsimulation calibration standards by several state and federal transportation authorities. A component of the calibration process is the calibration of the simulation for capacity. Capacity is a high-level measurement that is a function of many lowerlevel user-defined input parameters. VISSIM utilizes psychophysical car-following models that rely on ten userdefined parameters to represent freeway driving behavior. Several VISSIM driver behavior parameters have been shown to have a significant impact on roadway capacity. This paper seeks further understanding of the performance of the VISSIM traffic microsimulator by investigating the impact of driver behavior parameter combinations on a measure of freeway capacity. This paper is intended to provide insight useful for manual calibration of VISSIM microsimulation or the development of calibration algorithms.

Traffic flow is a complex phenomenon that needs better understanding of basic concepts and methods for its analysis. As a solution to practical problems, computer simulation has been proved to be a powerful tool in replicating complex traffic systems which allows experimentation to the basic traffic flow system. Various methods are available in literature, some of the methods use statistical tools to verify the difference between simulated and actual outputs and some are based on optimization which tries to minimize the error. For the present work, suitable methodology is adopted for the calibration process. Field data is collected, statistical tests are performed. For the simulation, VISSIM microscopic simulation tool is used and data analysis is performed by considering individual parameters and performance measures like speed, volume and random seed number. Statistical tests have been performed to check the sensitivity of the different simulation parameters. Calibration is done using trial and error method and optimization is performed using solver function. The maximum simulated flow rate was found with default values as 4599 veh/hr, and with calibrated values is 5147 veh/hr which is close to the target capacity 4958 veh/hr as obtained using field composition. Calibrated values of CC0 and CC1 and CC2 parameters were found as most optimized values to achieve target capacity. Finally, validation of calibrated parameter was performed by using different section of a multilane highway.

The present study uses the microscopic traffic simulation flow model VISSIM for generating traffic flow data to obtain the essential parameters. Study calibrated and validated the VISSIM model based on the field data. Further, lane change behaviour is analyzed with homogeneous vehicle type traffic on four-lane, six-lane and eight-lane divided highways sections through VISSIM simulation model. The study finds the number of lane changes depends on traffic volume as well as on a number of lanes provided for a direction of travel. Lane change data was correlated with traffic volume, and the third-degree polynomial trend was found to be fitted on each type of simulated highway sections. A maximum number of lane changes and lane change at the capacity level of the volume are also quantified on simulated sections of four-lane, six-lane and eight-lane divided highways.

The Impact of Autonomous Vehicles on Freeway Throughput Abdullah Maarafi Autonomous vehicles are expected to provide a number of benefits to the individual, road infrastructure and the society from the perspective of safety and efficiency. The use of autonomous vehicles is expected to increase freeway throughput, allowing vehicle groups travelling together with a shorter headway time resulting in a reduction of traffic congestion.

In this letter, we detail a modular approach for measuring the secondary physical and emotional effects of ambient intelligence (AmI) technology in traffic. Using the case of merges on to a highway, we assess the results of a system that advises the driver to change early to a lane on the left to create space for merging cars downstream (tested using a cellular automata simulation). The indirect impact of the system downstream, namely how the remaining lane changes from the merge lane to the innermost lane proceed, is then evaluated using a time-discrete, space-continuous microscopic traffic simulation tool. This yields detailed results concerning driver interactions that can also be used to derive an estimate of driver anger in the situation. We have used real geographic, traffic and psychological data to test the system, and different models are used to accomplish various tasks. The approach yields (surprisingly) negative results concerning the indirect emotional impact of this AmI intervention which may be due to the nature of the lane changing model used and the chosen parameters. We argue that such an approach is also applicable to similar types of systems, where different data and model types are suited to different scenario elements.

In this letter, we detail a modular approach for measuring the secondary physical and emotional effects of ambient intelligence (AmI) technology in traffic. Using the case of merges on to a highway, we assess the results of a system that advises the driver to change early to a lane on the left to create space for merging cars downstream (tested using a cellular automata simulation). The indirect impact of the system downstream, namely how the remaining lane changes from the merge lane to the innermost lane proceed, is then evaluated using a time-discrete, space-continuous microscopic traffic simulation tool. This yields detailed results concerning driver interactions that can also be used to derive an estimate of driver anger in the situation. We have used real geographic, traffic and psychological data to test the system, and different models are used to accomplish various tasks. The approach yields (surprisingly) negative results concerning the indirect emotional impact of this AmI intervention which may be due to the nature of the lane changing model used and the chosen parameters. We argue that such an approach is also applicable to similar types of systems, where different data and model types are suited to different scenario elements.

Simulation today is one of the most used tools in science and engineering. Traffic engineering is no exception. Simulators to be usable passes through processes of verification, validation and calibration. All simulators are based on assumptions and parameters that need to be calibrated so as to be practical in real world applications. Some parameters change from site to site. Therefore, the calibration process is often needed. Calibration can be seen as an optimization process that seeks to minimize the difference between observed and simulated measures. The question of which optimization technique suits more for this particular problem remains open. In this paper the convergence velocity of main heuristic optimization techniques, namely Genetic Algorithm (GA), Tabu Search (TS), Particle Swarm Optimization (PS) and Simultaneous Perturbation for Stochastic Approximation algorithm (SPSA) were used to calibrate a traffic simulation model called SUMO. The results of the calibration of the mentioned optimization techniques were compared. Classical optimization techniques, namely Neldear-Mead and COBYLA were used as a baseline comparison. Each technique has its own parameters that affect convergence velocity. Therefore, optimization techniques themselves need to be calibrated. However, TS and PS are not widely used to calibrate traffic simulators. They perform well in this particular problem. PS is highly parallel compared to the TS and SPSA. The paper shows that classical optimization techniques are not suitable for this particular problem, PS and TS appear to be better than GA and SPSA. PS seems to be a promising optimization technique.

Car-following models are used in microscopic simulation tools to calculate the longitudinal acceleration of a vehicle based on the speed and position of a leading vehicle in the same lane. Bicycle traffic is usually included in microscopic traffic simulations by adjusting and calibrating behavior models developed for motor vehicle traffic. However, very little work has been carried out to examine the following behavior of bicyclists, calibrate following models to fit this observed behavior, and determine the validity of these calibrated models. In this paper, microscopic trajectory data collected in a bicycle simulator study are used to estimate the following parameters of the psycho-physical Wiedemann 99 car-following model implemented in PTV Vissim. The Wiedemann 99 model is selected due to the larger number of assessable parameters and the greater possibility to calibrate the model to fit observed behavior. The calibrated model is validated using the indicator average queue dissipation time at a traffic light on the facilities ranging in width between 1.5 m to 2.5 m. Results show that the parameter set derived from the microscopic trajectory data creates more realistic simulated bicycle traffic than a suggested parameter set. However, it was not possible to achieve the large variation in average queue dissipation times that was observed in the field with either of the tested parameter sets.

Comprehensive analysis of traffic behavior requires continuous studies to develop traffic theories explaining that behavior at the microscopic level. The study aims to develop a microsimulation program to evaluate the freeway weaving performance depending on the observed data. FWASIM represents a microscopic analysis of the freeway traffic features. It scans events periodically. The developed FWASIM involves the formulation of driver and vehicle behavior at freeway link, on-ramp, off-ramp, and combine them to produce a flexible, friendly use simulation model. Its concept is mainly depending on the car following and lane change theories. Analytical model validation was conducted based on a comparison of FWASIM output with the VISSIM output. Tests consider the important factors that may affect the traffic behavior for a given segment configuration. The obtained results show agreement between FWASIM and VISSIM outputs. Besides, the field data were used to validate FWASIM. Graphical and t-test methods were used to examine the results. The results are statistically significant which implies that the model provides reasonably accurate measures of effectiveness for the validated range of input data.