In this paper, we develop a new car-following model with consideration of varying road condition ... more In this paper, we develop a new car-following model with consideration of varying road condition based on the empirical data. Firstly, we explore the effects of road condition on uniform flow from analytical and numerical perspectives. The results indicate that road condition has great influences on uniform flow, i.e., good road condition can enhance the velocity and flow and their increments will increase when road condition becomes better; bad road conditions will reduce the velocity and flow and their reductions will increase when road condition turns worse. Secondly, we study the effects of road conditions on the starting and braking processes. The numerical results show that good road condition will speed up the two processes and that bad road condition will slow down the two processes. Finally, we study the effects of road condition on small perturbation. The numerical results indicate that the stop-and-go phenomena resulted by small perturbation will become more serious when the road condition becomes better.
In this paper, we use empirical data to calibrate the speed-headway function and propose a car-fo... more In this paper, we use empirical data to calibrate the speed-headway function and propose a car-following model to investigate the effects of real-time road condition on each vehicle's speed, acceleration, headway, fuel consumption, CO, HC and NO X under uniform flow. Numerical results illustrate that real-time road condition produces oscillating phenomena and enhance each vehicle's fuel consumption and exhaust emissions. These results can help researchers understand the effects of real-time road condition on the driving behavior and help traffic engineers construct the theory of homogeneous roads in order to reduce the vehicle's fuel consumption and exhaust emissions.
In this paper, we develop a macro traffic flow model with consideration of varying road condition... more In this paper, we develop a macro traffic flow model with consideration of varying road conditions. Our analytical and numerical results illustrate that good road condition can enhance the speed and flow of uniform traffic flow whereas bad road condition will reduce the speed and flow. The numerical results also show that good road condition can smooth shock wave and improve the stability of traffic flow whereas bad road condition will lead to steeper shock wave and reduce the stability of traffic flow. Our results are also qualitatively accordant with empirical results, which implies that the proposed model can qualitatively describe the effects of road conditions on traffic flow. These results can guide traffic engineers to improve the road quality in traffic engineering. KEY WORDS: road condition; macro model; traffic flow the model cannot deviate from the equilibrium speed. To conquer this drawback, Payne [9] proposed the first high-order model (called the Payne model); Michalopoulos et al. [10] considered the impacts of the geometry of road structure on traffic flow and proposed a high-order model with consideration of the geometry of road structure; Zhang [11,12] constructed two high-order models based on the Payne model; Jiang et al. [13] developed a speed-gradient (SG) model from the full velocity difference (FVD) model [14], and Chang and Zhu [15] extended the model to the multi-lane traffic system and constructed a multi-lane traffic flow model; Gupta and Katiyar [16] established a dynamic model for multi-class traffic flow on the basis of the Payne model, and Gundaliya et al. [17] extended the work and developed a grid-based model to explore multi-class traffic flow; Tang et al. [18] further extended the SG model [13] and developed a two-lane traffic flow model with consideration of lane-changing; on the basis of the traffic flow model [15], Bie et al. [19] developed a lane-based method to evaluate the capacity of multi-lane traffic roundabout.
Proceedings of the Eastern Asia Society for …, 2005
This paper attempts to investigate the impact of the number of lanes on highway capacity. Methodo... more This paper attempts to investigate the impact of the number of lanes on highway capacity. Methodologically, we provide a better understanding of the relationship between highway capacity and its number of lanes upon the statistical analysis of the survey. We employ the variance analysis of single factor for modeling the effect of the number of lanes on capacity. The findings show that average capacity per lane decreases with increasing number of lanes on uninterrupted highway segments. The analysis is based on an extensive field survey of traffic flow in Beijing. The implication of the marginal decrease of lane capacity requires that the manuals of highway capacity should be revised for the better plan and design of road network. In addition, the factor of marginal decrease should be incorporated into the decision on adding lanes or constructing a new parallel road when travel demand exceeds road capacity.
To investigate the relationship between cyclist violation and waiting duration, the red-light run... more To investigate the relationship between cyclist violation and waiting duration, the red-light running behavior of nonmotorized vehicles is examined at signalized intersections. Violation waiting duration is collected by video cameras and it is assigned as censored and uncensored data to distinguish between normal crossing and red-light running. A proportional hazard-based duration model is introduced, and variables revealing personal characteristics and traffic conditions are used to describe the effects of internal and external factors. Empirical results show that the redlight running behavior of cyclist is time dependent. Cyclist's violating behavior represents positive duration dependence, that the longer the waiting time elapsed, the more likely cyclists would end the wait soon. About 32% of cyclists are at high risk of violation and low waiting time to cross the intersections. About 15% of all the cyclists are generally nonrisk takers who can obey the traffic rules after waiting for 95 seconds. The human factors and external environment play an important role in cyclists' violation behavior. Minimizing the effects of unfavorable condition in traffic planning and designing may be an effective measure to enhance traffic safety.
Abstract In this paper, computational models of environmental pollution and energy consumption of... more Abstract In this paper, computational models of environmental pollution and energy consumption of urban multimodal traffic network are proposed according to pertinent research and a multi-objective programming model is then developed to formulate ...
Real time system for vehicle travel time and traffic flow is an essential part of Intelligent Tra... more Real time system for vehicle travel time and traffic flow is an essential part of Intelligent Transportation Systems. In many Chinese cities, the interactions among buses, bicycles and cars bring difficulty to travel time prediction and traffic safety management. The aim of this paper is to develop a new model to estimate car travel time near bus stops in developing countries by data mining techniques and survival analysis methods. The travel time data under mixed traffic conditions are collected by video camera. Four influential factors including car volume, nonmotorized volume, bus departure volume and free ratio of bus stop are chosen by using data mining techniques. A proportional hazard-based duration model is proposed to analyze the factors related to car travel time. The results indicate that mixed traffic flow impacts the car travel time significantly. In addition, various factors can modify the travel time distribution in different degrees and the model can be used to estimate the travel time under assumed conditions. It is hoped to help improve the planning and designing of proper facilities with mixed traffic flow.
In this paper, we develop a new car-following model with consideration of varying road condition ... more In this paper, we develop a new car-following model with consideration of varying road condition based on the empirical data. Firstly, we explore the effects of road condition on uniform flow from analytical and numerical perspectives. The results indicate that road condition has great influences on uniform flow, i.e., good road condition can enhance the velocity and flow and their increments will increase when road condition becomes better; bad road conditions will reduce the velocity and flow and their reductions will increase when road condition turns worse. Secondly, we study the effects of road conditions on the starting and braking processes. The numerical results show that good road condition will speed up the two processes and that bad road condition will slow down the two processes. Finally, we study the effects of road condition on small perturbation. The numerical results indicate that the stop-and-go phenomena resulted by small perturbation will become more serious when the road condition becomes better.
In this paper, we use empirical data to calibrate the speed-headway function and propose a car-fo... more In this paper, we use empirical data to calibrate the speed-headway function and propose a car-following model to investigate the effects of real-time road condition on each vehicle's speed, acceleration, headway, fuel consumption, CO, HC and NO X under uniform flow. Numerical results illustrate that real-time road condition produces oscillating phenomena and enhance each vehicle's fuel consumption and exhaust emissions. These results can help researchers understand the effects of real-time road condition on the driving behavior and help traffic engineers construct the theory of homogeneous roads in order to reduce the vehicle's fuel consumption and exhaust emissions.
In this paper, we develop a macro traffic flow model with consideration of varying road condition... more In this paper, we develop a macro traffic flow model with consideration of varying road conditions. Our analytical and numerical results illustrate that good road condition can enhance the speed and flow of uniform traffic flow whereas bad road condition will reduce the speed and flow. The numerical results also show that good road condition can smooth shock wave and improve the stability of traffic flow whereas bad road condition will lead to steeper shock wave and reduce the stability of traffic flow. Our results are also qualitatively accordant with empirical results, which implies that the proposed model can qualitatively describe the effects of road conditions on traffic flow. These results can guide traffic engineers to improve the road quality in traffic engineering. KEY WORDS: road condition; macro model; traffic flow the model cannot deviate from the equilibrium speed. To conquer this drawback, Payne [9] proposed the first high-order model (called the Payne model); Michalopoulos et al. [10] considered the impacts of the geometry of road structure on traffic flow and proposed a high-order model with consideration of the geometry of road structure; Zhang [11,12] constructed two high-order models based on the Payne model; Jiang et al. [13] developed a speed-gradient (SG) model from the full velocity difference (FVD) model [14], and Chang and Zhu [15] extended the model to the multi-lane traffic system and constructed a multi-lane traffic flow model; Gupta and Katiyar [16] established a dynamic model for multi-class traffic flow on the basis of the Payne model, and Gundaliya et al. [17] extended the work and developed a grid-based model to explore multi-class traffic flow; Tang et al. [18] further extended the SG model [13] and developed a two-lane traffic flow model with consideration of lane-changing; on the basis of the traffic flow model [15], Bie et al. [19] developed a lane-based method to evaluate the capacity of multi-lane traffic roundabout.
Proceedings of the Eastern Asia Society for …, 2005
This paper attempts to investigate the impact of the number of lanes on highway capacity. Methodo... more This paper attempts to investigate the impact of the number of lanes on highway capacity. Methodologically, we provide a better understanding of the relationship between highway capacity and its number of lanes upon the statistical analysis of the survey. We employ the variance analysis of single factor for modeling the effect of the number of lanes on capacity. The findings show that average capacity per lane decreases with increasing number of lanes on uninterrupted highway segments. The analysis is based on an extensive field survey of traffic flow in Beijing. The implication of the marginal decrease of lane capacity requires that the manuals of highway capacity should be revised for the better plan and design of road network. In addition, the factor of marginal decrease should be incorporated into the decision on adding lanes or constructing a new parallel road when travel demand exceeds road capacity.
To investigate the relationship between cyclist violation and waiting duration, the red-light run... more To investigate the relationship between cyclist violation and waiting duration, the red-light running behavior of nonmotorized vehicles is examined at signalized intersections. Violation waiting duration is collected by video cameras and it is assigned as censored and uncensored data to distinguish between normal crossing and red-light running. A proportional hazard-based duration model is introduced, and variables revealing personal characteristics and traffic conditions are used to describe the effects of internal and external factors. Empirical results show that the redlight running behavior of cyclist is time dependent. Cyclist's violating behavior represents positive duration dependence, that the longer the waiting time elapsed, the more likely cyclists would end the wait soon. About 32% of cyclists are at high risk of violation and low waiting time to cross the intersections. About 15% of all the cyclists are generally nonrisk takers who can obey the traffic rules after waiting for 95 seconds. The human factors and external environment play an important role in cyclists' violation behavior. Minimizing the effects of unfavorable condition in traffic planning and designing may be an effective measure to enhance traffic safety.
Abstract In this paper, computational models of environmental pollution and energy consumption of... more Abstract In this paper, computational models of environmental pollution and energy consumption of urban multimodal traffic network are proposed according to pertinent research and a multi-objective programming model is then developed to formulate ...
Real time system for vehicle travel time and traffic flow is an essential part of Intelligent Tra... more Real time system for vehicle travel time and traffic flow is an essential part of Intelligent Transportation Systems. In many Chinese cities, the interactions among buses, bicycles and cars bring difficulty to travel time prediction and traffic safety management. The aim of this paper is to develop a new model to estimate car travel time near bus stops in developing countries by data mining techniques and survival analysis methods. The travel time data under mixed traffic conditions are collected by video camera. Four influential factors including car volume, nonmotorized volume, bus departure volume and free ratio of bus stop are chosen by using data mining techniques. A proportional hazard-based duration model is proposed to analyze the factors related to car travel time. The results indicate that mixed traffic flow impacts the car travel time significantly. In addition, various factors can modify the travel time distribution in different degrees and the model can be used to estimate the travel time under assumed conditions. It is hoped to help improve the planning and designing of proper facilities with mixed traffic flow.
This paper attempts to investigate the impact of the number of lanes on highway capacity. Methodo... more This paper attempts to investigate the impact of the number of lanes on highway capacity. Methodologically, we provide a better understanding of the relationship between highway capacity and its number of lanes upon the statistical analysis of the survey. We employ the variance analysis of single factor for modeling the effect of the number of lanes on capacity. The findings show that average capacity per lane decreases with increasing number of lanes on uninterrupted highway segments. The analysis is based on an extensive field survey of traffic flow in Beijing. The implication of the marginal decrease of lane capacity requires that the manuals of highway capacity should be revised for the better plan and design of road network. In addition, the factor of marginal decrease should be incorporated into the decision on adding lanes or constructing a new parallel road when travel demand exceeds road capacity.
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