Shahriar Afandizadeh Zargari - Academia.edu (original) (raw)

Papers by Shahriar Afandizadeh Zargari

Nonlinear Engineering, 2021

Sustainability, Feb 22, 2016

Nonlinear Engineering

In this study, the gray box method has been used to model traffic accidents for the first time. T... more In this study, the gray box method has been used to model traffic accidents for the first time. This work examines the problem of estimating and identifying a single-input single-output state-space system. In this way, the state-space model was used, which has both a black box section (experimental data) and the parameters have been estimated by acquiring prior knowledge (white box). First, the state-space of the desired system is formed, and the algorithm for estimating the parameters and their convergence and the state vector estimation algorithm are written. In comparison, the system changes from nonlinear to linear. The parameters and prior knowledge are entered from the system. Finally, by implementing the presented method on the data related to the factors affecting accidents in Qazvin (Iran), the accuracy of the presented materials is investigated. The error output shows that initially, the error increased slightly, but then it shows a downward trend, and with the increase in...

Iranian Journal of Science and Technology, Transactions of Civil Engineering

Transportation Letters: The International Journal of Transportation Research, Dec 28, 2022

Iranian Journal of Science and Technology, Transactions of Civil Engineering

Innovative Infrastructure Solutions

Travel time reliability (TTR) is known as the temporal variability of travel time and influences ... more Travel time reliability (TTR) is known as the temporal variability of travel time and influences many aspects of the traveler's decisions, especially in roadway transport. Investigating literature review shows seven factors can cause congestion and affect travel time reliability. Three of the most common factors investigated in numerous studies include traffic incidents, adverse weather, and traffic volume. Most of the previous studies have focused on modeling the variations of a single variable on the dependent variable (reliability metric), and those considered multivariate analyses have used traditional tools like linear regression. This paper investigates the effects of traffic volume, weather conditions, and traffic incidents on the planning time index (PTI) as a dependent variable in Virginia's interstate highways. Six machine learning (ML) techniques: neural network (NN), support vector regression (SVR), linear, polynomial, and radial basis function (RBF) kernel functions, K-nearest neighbors (KNN), and decision tree (DT) and five ordinary least squares (OLS) linear regression models including linear, inverse, growth, power, and S-shaped functions were used to analyze TTR in this study. Analyzing coefficients, root mean square error (RMSE), and stability of models besides using statistical measures of error terms of maximum, standard deviation, and mean outlined that KNN is the best model for estimating TTR.

International Journal of Transportation Science and Technology

Iranian Journal of Science and Technology, Transactions of Civil Engineering, 2022

In this paper a new approach for bus network design have been presented, these two approaches tak... more In this paper a new approach for bus network design have been presented, these two approaches take into account the effects of three stages out of the four steps of the bus planning process. The introduced model includes three major steps; 1- Network Design Procedure (NDP). 2- Frequency Determination and Assignment Procedure (FDAP). 3- Network Evaluation Procedure (NEP). Genetic Algorithm has been used for the solution of this problem, because of its capability for solving large and complex problems. Two genetic Algorithms coding have been developed in the present paper; the first model is good for small and medium networks and the second one is good for medium and large networks. Optimization of bus assignment to depots is another important issue in the bus system planning process that has been inserted in the presented model. Finally, our model has been tested on Mandl’s bus network that is a benchmark Swiss network and has been initially used by Mandl and later by Baaj and Mahmas...

In weaving section due to a strong need for lane changing, a type of turbulence is created in tra... more In weaving section due to a strong need for lane changing, a type of turbulence is created in traffic flow; so, the speedand the capacity of the weaving section decreases. Therefore, investigation of the weaving section is very important.However, due to shortage of the manual for urban principal arterials (highways), calibration of these models is necessary.One of these models that are used to evaluate the level of service of the weaving sections is speed model whichwill be developed in this paper. Thus, data of the lane-changing rates and travel time (speed) have been collected in9 principal arterials of Tehran. Then, two models for estimating of weaving and non-weaving speed are developed.Validations also confirm the accuracy of the developed models. Exploration of these developed models reveals thatspeed decreases by increasing the weaving intensity. In addition, Comparison of the developed models and HCM 2010for similar condition shows that the developed models estimate more tha...

Transportation in Developing Economies, 2021

This paper investigates the issue of spatial equity in the cordon pricing scheme. The spatial ine... more This paper investigates the issue of spatial equity in the cordon pricing scheme. The spatial inequity is for drivers whose travel destinations are located within the cordon or should travel through it and finally they may face with higher travel time. Thus, to alleviate this inequity, a bi-level multi-objective optimization model is developed. Next, an algorithm is implemented according to the second version of the Strength Pareto Evolutionary Algorithm (SPEA2). Then, the developed model is applied to Sioux Falls network and the results is discussed. The results reveal that it seems reasonable to consider spatial equity as an objective function in cordon pricing. In addition, we can create a sustainable situation for the transportation system by improving spatial inequity with a relatively low reduction in social welfare. Moreover, there are spatial inequity impacts in real networks, which should be considered in the cordon pricing scheme. Furthermore, the developed model can increase the public acceptance of drivers and transportation authorities.

Journal of Advanced Transportation, 2020

Travellers have to make some decisions for each trip, and one of them is the choice of departure ... more Travellers have to make some decisions for each trip, and one of them is the choice of departure time. Discrete choice models have been employed as an approach to departure time modelling by many researchers. In this method, preparing choice set is a primary challenge which involves the definition of some departure periods to be selected by the traveller. In this research, choice sets were formed by applying the clustering methods on departure times. Afterwards, we developed Multinomial Logit (MNL) models on different choice sets and compared the models. The data used throughout this research belonged to Mashhad City. Research results indicated that Ward’s hierarchical clustering method is improper for time discretization; furthermore, the K-means clustering method is more efficient than the expectation maximization and K-medoids methods in the time discretization for MNL modelling. The developed model (based on K-means clustering method) accurately predicts departure time for 58% o...

Proceedings of the Institution of Civil Engineers - Transport, 2018

The accessibility of advanced technology now provides an opportunity for researchers to resolve r... more The accessibility of advanced technology now provides an opportunity for researchers to resolve road safety problems by analysing violent manoeuvres of vehicles as a surrogate measurement. This study investigated the possibility that the numbers of deceleration records of sample vehicles (deceleration numbers) could be used as a surrogate measurement for crash data in road safety analyses. To this end, deceleration numbers at different intensities were obtained through real-time data (at 1 s intervals) from smartphone sensors. The correlation between deceleration numbers (at different intensities) was then examined based on valid safety parameters (crash rate, crash frequency, crashes involving fatality or injury and damage-only crashes). The results demonstrated a substantial correlation between the empirical Bayesian parameter and deceleration numbers. The Spearman correlation coefficient between the two parameters was 0·794 (at a very high significance level), which is notable fr...

Computers & concrete, 2013

Abstract. One of the major benefits of the pre-stressed concrete pavements is the omission of ten... more Abstract. One of the major benefits of the pre-stressed concrete pavements is the omission of tension in concrete that results in a reduction of cracks in the concrete slabs. Therefore, the life of the pavement is in-creased as the thickness of the slabs is reduced. One of the most important issues in dealing with the pre-stressed concrete pavement is determination of the magnitude of the pre-stress. Three dimensional finite element analyses are conducted in this research to study the pre-stress under various load (Boeing 777) and thermal gradient combinations. The model was also analyzed under temperature gradients without the pres-ence of traffic loading and the induced stresses were compared with those from theoretical relationships. It was seen that the theoretical relationships result in conservative values for the stress. Keywords: thermal stress; pre stressed concrete pavement; finite element 1. Introduction The use of pre-stressed concrete pavements has received considerable attention for years as a measure for extending the service life of pavements yet remaining cost-effective. It is well understood that conventional concrete pavements are designed taking into account the fundamental flexural and tensile weakness of concrete slabs. In pre-stressed concrete pavements the pre-compression induced by pre-stressing, results in greater allowable flexural and tensile stresses which can lead to a reduced design thickness for the concrete slabs as well as an increased service life in comparison with the conventional concrete pavements.

INTERNATIONAL JOURNAL FOR TRAFFIC AND TRANSPORT ENGINEERING, 2015

In this paper, a new approach was presented for bus network design which took the effects of thre... more In this paper, a new approach was presented for bus network design which took the effects of three out of four stages of the bus planning process into account. The presented model consisted of three majors steps; 1- Network Design Procedure (NDP), 2- Frequency Determination and Assignment Procedure (FDAP), and 3- Network Evaluation Procedure (NEP). Genetic Algorithm (GA) was utilized to solve this problem since it was capable of solving large and complex problems. Optimization of bus assignment at depots is another important issue in bus system planning process which was considered in the presented model. In fact, the present model was tested on Mandl’s bus network which was a benchmark in Swiss network and was initially employed by Mandl and later by Baaj, Mahmassani, Kidwai, Chakroborty and Zhao. Several comparisons indicated that the model presented in this paper was superior to the previous models. Meanwhile, none of the previous approaches optimized depots assignment. Afterward...

Nonlinear Engineering, 2021

Sustainability, Feb 22, 2016

Nonlinear Engineering

In this study, the gray box method has been used to model traffic accidents for the first time. T... more In this study, the gray box method has been used to model traffic accidents for the first time. This work examines the problem of estimating and identifying a single-input single-output state-space system. In this way, the state-space model was used, which has both a black box section (experimental data) and the parameters have been estimated by acquiring prior knowledge (white box). First, the state-space of the desired system is formed, and the algorithm for estimating the parameters and their convergence and the state vector estimation algorithm are written. In comparison, the system changes from nonlinear to linear. The parameters and prior knowledge are entered from the system. Finally, by implementing the presented method on the data related to the factors affecting accidents in Qazvin (Iran), the accuracy of the presented materials is investigated. The error output shows that initially, the error increased slightly, but then it shows a downward trend, and with the increase in...

Iranian Journal of Science and Technology, Transactions of Civil Engineering

Transportation Letters: The International Journal of Transportation Research, Dec 28, 2022

Iranian Journal of Science and Technology, Transactions of Civil Engineering

Innovative Infrastructure Solutions

Travel time reliability (TTR) is known as the temporal variability of travel time and influences ... more Travel time reliability (TTR) is known as the temporal variability of travel time and influences many aspects of the traveler's decisions, especially in roadway transport. Investigating literature review shows seven factors can cause congestion and affect travel time reliability. Three of the most common factors investigated in numerous studies include traffic incidents, adverse weather, and traffic volume. Most of the previous studies have focused on modeling the variations of a single variable on the dependent variable (reliability metric), and those considered multivariate analyses have used traditional tools like linear regression. This paper investigates the effects of traffic volume, weather conditions, and traffic incidents on the planning time index (PTI) as a dependent variable in Virginia's interstate highways. Six machine learning (ML) techniques: neural network (NN), support vector regression (SVR), linear, polynomial, and radial basis function (RBF) kernel functions, K-nearest neighbors (KNN), and decision tree (DT) and five ordinary least squares (OLS) linear regression models including linear, inverse, growth, power, and S-shaped functions were used to analyze TTR in this study. Analyzing coefficients, root mean square error (RMSE), and stability of models besides using statistical measures of error terms of maximum, standard deviation, and mean outlined that KNN is the best model for estimating TTR.

International Journal of Transportation Science and Technology

Iranian Journal of Science and Technology, Transactions of Civil Engineering, 2022

In this paper a new approach for bus network design have been presented, these two approaches tak... more In this paper a new approach for bus network design have been presented, these two approaches take into account the effects of three stages out of the four steps of the bus planning process. The introduced model includes three major steps; 1- Network Design Procedure (NDP). 2- Frequency Determination and Assignment Procedure (FDAP). 3- Network Evaluation Procedure (NEP). Genetic Algorithm has been used for the solution of this problem, because of its capability for solving large and complex problems. Two genetic Algorithms coding have been developed in the present paper; the first model is good for small and medium networks and the second one is good for medium and large networks. Optimization of bus assignment to depots is another important issue in the bus system planning process that has been inserted in the presented model. Finally, our model has been tested on Mandl’s bus network that is a benchmark Swiss network and has been initially used by Mandl and later by Baaj and Mahmas...

In weaving section due to a strong need for lane changing, a type of turbulence is created in tra... more In weaving section due to a strong need for lane changing, a type of turbulence is created in traffic flow; so, the speedand the capacity of the weaving section decreases. Therefore, investigation of the weaving section is very important.However, due to shortage of the manual for urban principal arterials (highways), calibration of these models is necessary.One of these models that are used to evaluate the level of service of the weaving sections is speed model whichwill be developed in this paper. Thus, data of the lane-changing rates and travel time (speed) have been collected in9 principal arterials of Tehran. Then, two models for estimating of weaving and non-weaving speed are developed.Validations also confirm the accuracy of the developed models. Exploration of these developed models reveals thatspeed decreases by increasing the weaving intensity. In addition, Comparison of the developed models and HCM 2010for similar condition shows that the developed models estimate more tha...

Transportation in Developing Economies, 2021

This paper investigates the issue of spatial equity in the cordon pricing scheme. The spatial ine... more This paper investigates the issue of spatial equity in the cordon pricing scheme. The spatial inequity is for drivers whose travel destinations are located within the cordon or should travel through it and finally they may face with higher travel time. Thus, to alleviate this inequity, a bi-level multi-objective optimization model is developed. Next, an algorithm is implemented according to the second version of the Strength Pareto Evolutionary Algorithm (SPEA2). Then, the developed model is applied to Sioux Falls network and the results is discussed. The results reveal that it seems reasonable to consider spatial equity as an objective function in cordon pricing. In addition, we can create a sustainable situation for the transportation system by improving spatial inequity with a relatively low reduction in social welfare. Moreover, there are spatial inequity impacts in real networks, which should be considered in the cordon pricing scheme. Furthermore, the developed model can increase the public acceptance of drivers and transportation authorities.

Journal of Advanced Transportation, 2020

Travellers have to make some decisions for each trip, and one of them is the choice of departure ... more Travellers have to make some decisions for each trip, and one of them is the choice of departure time. Discrete choice models have been employed as an approach to departure time modelling by many researchers. In this method, preparing choice set is a primary challenge which involves the definition of some departure periods to be selected by the traveller. In this research, choice sets were formed by applying the clustering methods on departure times. Afterwards, we developed Multinomial Logit (MNL) models on different choice sets and compared the models. The data used throughout this research belonged to Mashhad City. Research results indicated that Ward’s hierarchical clustering method is improper for time discretization; furthermore, the K-means clustering method is more efficient than the expectation maximization and K-medoids methods in the time discretization for MNL modelling. The developed model (based on K-means clustering method) accurately predicts departure time for 58% o...

Proceedings of the Institution of Civil Engineers - Transport, 2018

The accessibility of advanced technology now provides an opportunity for researchers to resolve r... more The accessibility of advanced technology now provides an opportunity for researchers to resolve road safety problems by analysing violent manoeuvres of vehicles as a surrogate measurement. This study investigated the possibility that the numbers of deceleration records of sample vehicles (deceleration numbers) could be used as a surrogate measurement for crash data in road safety analyses. To this end, deceleration numbers at different intensities were obtained through real-time data (at 1 s intervals) from smartphone sensors. The correlation between deceleration numbers (at different intensities) was then examined based on valid safety parameters (crash rate, crash frequency, crashes involving fatality or injury and damage-only crashes). The results demonstrated a substantial correlation between the empirical Bayesian parameter and deceleration numbers. The Spearman correlation coefficient between the two parameters was 0·794 (at a very high significance level), which is notable fr...

Computers & concrete, 2013

Abstract. One of the major benefits of the pre-stressed concrete pavements is the omission of ten... more Abstract. One of the major benefits of the pre-stressed concrete pavements is the omission of tension in concrete that results in a reduction of cracks in the concrete slabs. Therefore, the life of the pavement is in-creased as the thickness of the slabs is reduced. One of the most important issues in dealing with the pre-stressed concrete pavement is determination of the magnitude of the pre-stress. Three dimensional finite element analyses are conducted in this research to study the pre-stress under various load (Boeing 777) and thermal gradient combinations. The model was also analyzed under temperature gradients without the pres-ence of traffic loading and the induced stresses were compared with those from theoretical relationships. It was seen that the theoretical relationships result in conservative values for the stress. Keywords: thermal stress; pre stressed concrete pavement; finite element 1. Introduction The use of pre-stressed concrete pavements has received considerable attention for years as a measure for extending the service life of pavements yet remaining cost-effective. It is well understood that conventional concrete pavements are designed taking into account the fundamental flexural and tensile weakness of concrete slabs. In pre-stressed concrete pavements the pre-compression induced by pre-stressing, results in greater allowable flexural and tensile stresses which can lead to a reduced design thickness for the concrete slabs as well as an increased service life in comparison with the conventional concrete pavements.

INTERNATIONAL JOURNAL FOR TRAFFIC AND TRANSPORT ENGINEERING, 2015

In this paper, a new approach was presented for bus network design which took the effects of thre... more In this paper, a new approach was presented for bus network design which took the effects of three out of four stages of the bus planning process into account. The presented model consisted of three majors steps; 1- Network Design Procedure (NDP), 2- Frequency Determination and Assignment Procedure (FDAP), and 3- Network Evaluation Procedure (NEP). Genetic Algorithm (GA) was utilized to solve this problem since it was capable of solving large and complex problems. Optimization of bus assignment at depots is another important issue in bus system planning process which was considered in the presented model. In fact, the present model was tested on Mandl’s bus network which was a benchmark in Swiss network and was initially employed by Mandl and later by Baaj, Mahmassani, Kidwai, Chakroborty and Zhao. Several comparisons indicated that the model presented in this paper was superior to the previous models. Meanwhile, none of the previous approaches optimized depots assignment. Afterward...