Characteristics of mixed traffic on urban arterials with significant volumes of motorized two-wheelers: role of composition, intraclass variability, and lack of lane discipline
01 Jan 2012-Transportation Research Record (Transportation Research Board of the National Academies)-Vol. 2317, Iss: 2317, pp 51-59
TL;DR: The preliminary analysis indicated that factors such as composition, intraclass variability, and lane discipline had a statistically significant effect on stream speed, and the results showed the promise of some measures based on vehicle class, namely, the exclusion of autorickshaws or autorickhaws and heavy vehicles.
Abstract: Mixed traffic in the cities of many developing countries is characterized by a lack of lane discipline, varying compositions of constituent vehicle types, and significant intraclass variability in static and dynamic characteristics. However, the influence of these factors on traffic flow parameters is not well understood. This study addressed the influence of lane discipline, intraclass variability, and composition on traffic flow characteristics under heterogeneous traffic conditions in Chennai, India. A microscopic traffic simulation model was calibrated and validated with field data from a four-lane divided urban arterial road in Chennai. The preliminary analysis indicated that factors such as composition, intraclass variability, and lane discipline had a statistically significant effect on stream speed. Speed-flow and speed-density relationships were developed on the basis of simulation results. These results showed a clear influence of lack of lane discipline, variability, and composition on stream s...
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TL;DR: The results show statistically significant differences between the various vehicle types in travel speeds, accelerations, distance keeping, and selection of lateral positions on the roadway and suggest directions for development of a driving behavior model for mixed traffic streams.
Abstract: Models of driving behavior (e.g., car following and lane changing) describe the longitudinal and lateral movements of vehicles in the traffic stream. Calibration and validation of these models require detailed vehicle trajectory data. Trajectory data about traffic in cities in the developing world are not publicly available. These cities are characterized by a heterogeneous mix of vehicle types and by a lack of lane discipline. This paper reports on an effort to create a data set of vehicle trajectory data in mixed traffic and on the first results of analysis of these data. The data were collected through video photography in an urban midblock road section in Chennai, India. The trajectory data were extracted from the video sequences with specialized software, and the locally weighted regression method was used to process the data to reduce measurement errors and obtain continuous position, speed, and acceleration functions. The collected data were freely available at http://toledo.net.technion.ac.il/down...
95 citations
Cites background from "Characteristics of mixed traffic on..."
...However, calibration and validation of driving behavior, in the context of mixed traffic modeling, have mostly been based on macroscopic flow characteristics, such as flows, speeds and densities (16, 17)....
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24 Aug 2016
TL;DR: In this article, a review of current driving behavior models in the context of mixed traffic, discusses their limitations and the data and modeling challenges that need to be met in order to extend and improve their fidelity.
Abstract: Most published microscopic driving behavior models, such as car following and lane changing, were developed for homogeneous and lane-based settings. In the emerging and developing world, traffic is characterized by a wide mix of vehicle types (e.g., motorized and non-motorized, two, three and four wheelers) that differ substantially in their dimensions, performance capabilities and driver behavior and by a lack of lane discipline. This paper presents a review of current driving behavior models in the context of mixed traffic, discusses their limitations and the data and modeling challenges that need to be met in order to extend and improve their fidelity. The models discussed include those for longitudinal and lateral movements and gap acceptance. The review points out some of the limitations of current models. A main limitation of current models is that they have not explicitly considered the wider range of situations that drivers in mixed traffic may face compared to drivers in homogeneous lane-based traffic, and the strategies that they may choose in order to tackle these situations. In longitudinal movement, for example, such strategies include not only strict following, but also staggered following, following between two vehicles and squeezing. Furthermore, due to limited availability of trajectory data in mixed traffic, most of the models are not estimated rigorously. The outline of modeling framework for integrated driver behavior was discussed finally.
60 citations
Cites background or methods from "Characteristics of mixed traffic on..."
...[66] and Mathew and Ravishankar [67] simulated mixed traffic using vehicle type-specific parameters in car following models....
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...[75], Choudhry [76]) However, in the context of mixed traffic calibration and validation have mostly been based on macroscopic flow characteristics, such as flows, speeds and densities [8-9, 66, 77]....
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TL;DR: Gipps model is able to replicate the field conditions better than other models in non-steady state and has interesting implications for capacity and PCU estimation and Level of Service (LoS) Analysis.
58 citations
TL;DR: The performance of different vehicle-following models was evaluated based on different Measure of Effectiveness (MoE) using field data collected from a four-lane divided urban arterial road in Chennai city and the results showed the promise of some measures based on vehicle class.
Abstract: To understand the congestion problem and the occurrence of bottlenecks and to formulate solutions for it, a thorough study of vehicle-to-vehicle interactions is necessary. Car-following models replicate the behavior of a driver following another vehicle. These models are widely used in the development of traffic simulation models, and in analysis of safety and capacity. In India, traffic on roads is mixed in nature with wide variations in physical dimensions and other vehicular and traffic characteristics with loose lane discipline. In mixed traffic conditions, leader-follower vehicle types are not only car–car cases but also there are different combinations of vehicles (e.g. car-two wheeler, two wheeler-auto rickshaw, and heavy vehicle-two wheeler). The present study focuses on evaluation of different vehicle-following models under mixed traffic conditions. The car-following models such as Gipps, Intelligent Driver Model (IDM), Krauss Model and Das and Asundi were selected for this study. These m...
53 citations
Cites methods from "Characteristics of mixed traffic on..."
...Asaithambi et al. (2012) studied the influence of lane discipline, intra-class variability, and composition on traffic flow characteristics under heterogeneous traffic conditions using simulation model and evaluated a range of traffic control measures based on vehicle type and lane....
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...For this purpose, a microscopic traffic simulation model for mixed traffic conditions developed by Asaithambi et al. (2012) is adapted by incorporating various types of vehicle-following models under mixed traffic conditions....
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01 Jun 2019
TL;DR: The objective was to establish an experimental procedure and show direct AFM measurements that unequivocally can be assigned as reliable guideposts for the determination of PCU values.
Abstract: Estimation of passenger car unit (PCU) values is very important for traffic capacity analysis and other relevant applications such as level of service (LOS) measures, determination of satur...
23 citations
References
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TL;DR: In this article, a new concept to estimate the passenger car unit (PCU) of different types of vehicles under mixed traffic conditions is presented, which utilizes the area, as opposed to only the length, and speed of a vehicle.
Abstract: A new concept to estimate the passenger car unit (PCU) of different types of vehicles under mixed traffic conditions is presented. It utilizes the area, as opposed to only the length, and speed of a vehicle. Data were collected at ten sections of two-lane roads in different parts of India. The width of carriageway (this term is commonly used in India for the total width of the paved surface of a road excluding its shoulders) ranged from 5.5 to 8.8 m. All vehicles were divided into nine different categories and their PCU's were estimated at each road section. It was found that the PCU for a vehicle type increases linearly with the width of carriageway. This is attributed to the greater freedom of movement on wider roads and therefore a greater speed differential between a car and a vehicle type. The capacity of a two-lane road also increases with total width of the carriageway and the relationship between the two follows a second-degree curve. This relationship is used to derive the adjustment factors for substandard lane widths and the results are compared with literature.
211 citations
"Characteristics of mixed traffic on..." refers background in this paper
...Chandra and Kumar studied the effect of lane width on the passenger car unit (PCU) for different categories of vehicles and on the capacity of a two-lane road (2)....
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TL;DR: A model developed specifically for mixed streams covers different vehicle types, including nonmotorized ones, and allows for some special behaviors, such as seepage to fronts of queues by two-wheeled vehicles and simultaneous use of two lanes.
Abstract: Mixed-traffic streams that contain motorized and nonmotorized vehicles are becoming more common in urban areas. These streams contain standard vehicle types such as private cars, buses, and trucks, as well as nonstandard vehicles such as bicycles, motorcycles, and other vehicular forms. Models suitable for analysis of such streams hardly exist, and most available models are limited in scope and effectiveness. Analysis of mixed streams that use traditional approaches has achieved limited success and has involved much recalibration effort and significant model modifications. Effective analysis of these streams therefore inevitably requires new models to be developed that use different approaches. Aspects of a model developed specifically for mixed streams are presented. This model covers different vehicle types, including nonmotorized ones, and allows for some special behaviors, such as seepage to fronts of queues by two-wheeled vehicles and simultaneous use of two lanes. In addition to normal car-following...
73 citations
"Characteristics of mixed traffic on..." refers methods in this paper
...Oketch developed a simulation model with a new modeling approach for mixed traffic (1)....
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TL;DR: An attempt to modify the widely used Gipps’s car-following model to incorporate vehicle-type dependent parameters and indicates the need of incorporating vehicle- type combination specific parameters into traffic simulation models.
Abstract: Car-following behavior forms the kernel of traffic microsimulation models and is extensively studied for similar vehicle types. However, in heterogeneous traffic having a diverse mix of vehicles, following behavior also depends on the type of both the leader and following vehicles. This paper is an attempt to modify the widely used Gipps’s car-following model to incorporate vehicle-type dependent parameters. Performance of the model is studied at microscopic and macroscopic levels using data collected from both homogeneous and heterogeneous traffic conditions. The results indicate that the proposed modifications enhance the prediction of follower behavior and suggest the need of incorporating vehicle-type combination specific parameters into traffic simulation models.
53 citations
"Characteristics of mixed traffic on..." refers methods in this paper
...The Gipps model was used for car-following logic, because in mixed traffic, following behavior is based on the type of both the lead and the following vehicles (9)....
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TL;DR: The development of a model through object oriented programming (OOP) approach for simulating heterogeneous traffic in India and the various logics of simulation such as vehicle generation, vehicle placement and vehicle movement are presented.
Abstract: Roads in India carry heterogeneous traffic with wide variations in static and dynamic characteristics of vehicles. The traffic flow is also generally devoid of lane discipline, with vehicles occupying any available road space ahead. Modeling of such heterogeneous traffic is generally complex in nature and simulation has been proven to be effective in studying such traffic. This paper presents the development of a model through object oriented programming (OOP) approach for simulating heterogeneous traffic. Several unique traffic characteristics have been considered in the modeling process. C++ language is used for this purpose. OOP leads to better structured codes for simulation and facilitates the development, maintainability and expandability of such codes. The first part of the paper explains the various logics of simulation such as vehicle generation, vehicle placement and vehicle movement. The second part of the paper describes the features of OOP, description of classes and class relationships. The ...
50 citations
01 Jan 2011
TL;DR: Comparison of headway distributions across two facility types is made and it is observed that most of the pairs, particularly two wheeler, Auto rickshaw, pairs fit in same distribution irrespective of facility types.
Abstract: Time headway between vehicles is an important traffic flow characteristic affecting safety, level of service, driver behavior, and capacity of a transportation system. However, almost all the reported research on headway is focused on mixed vehicular flow without considering the difference in headway with respect to different lead and lag vehicle types. In this paper, different pairs of time headway based on different combinations of leading vehicle and following vehicle (Ex: Two wheeler-Two wheeler, Two wheeler-car, Two wheeler-Auto Rickshaw , etc.) are studied under heterogeneous traffic conditions. Monte-Carlo simulation procedure to simulate traffic stream headways based on the classwise distributions is discussed. The study of effect of lane and non lane discipline on headways shows that non-lane based discipline is appropriate for heterogeneous traffic conditions. Comparison of headway distributions across two facility types (two and three lane) is made and observed that most of the pairs, particularly two wheeler, Auto rickshaw, pairs fit in same distribution irrespective of facility types. The results of the paper identify difference of the vehicle-type-specific headway distribution, which can be used as a reference for practical applications, especially for improving microscopic traffic simulation models. They can also give insight on devising better planning and management of traffic and there by lead to better tools for traffic engineers and managers.
9 citations
"Characteristics of mixed traffic on..." refers methods in this paper
...Time-gap distributions for different categories based on lead–lag vehicles are given as input to the simulation model (8)....
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