Ali Zockaie

Ali Zockaie
Michigan State University | MSU · Department of Civil and Environmental Engineering

PhD, Northwestern University

About

49
Publications
10,147
Reads
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1,028
Citations

Publications

Publications (49)
Preprint
Managing a fleet of vehicles requires assets and operational analysis. The output of such analysis includes the number and type of the active, stored, salvaged, and purchased vehicles in the fleet and the operation requirements (i.e., refueling and maintenance) of these vehicles. Maintenance, operation, fuel, storage, and purchase costs are among t...
Article
Connected and autonomous vehicle technologies are expected to alter transportation systems by enhancements in mobility, safety, and emission reduction. While many studies have investigated the impacts of connected vehicle (CV) and autonomous vehicle (AV) technologies on traffic congestion and emission at the facility level, little is known about th...
Article
Congestion pricing is proposed as an effective travel demand management strategy to circumvent the problem of congestion and generate revenue to finance developmental projects. There are several studies focusing on optimal pricing strategies to minimize the congestion level or maximize the revenue of the system. However, with regard to equity issue...
Article
Snow removal activities are performed by roadway agencies to enhance winter mobility and safety. Slower travel speeds during these operations, combined with low visibility and reduced pavement friction, mean that safety and collision avoidance remain a persistent concern. Many studies have implemented signing and lighting technologies to improve th...
Article
Electric vehicles (EV) are widely seen as a sustainable alternative to gasoline vehicles to decrease emissions and dependence on fossil fuels. However, range anxiety, limited range, long charging time, and insufficient charging infrastructure have affected EVs’ adoption. High-end batteries and chargers can decrease the charging demand and charging...
Article
Electric vehicles are a sustainable substitution to conventional vehicles. This study introduces an integrated framework for urban fast charging infrastructure to address the range anxiety issue. A mesoscopic simulation tool is developed to generate trip trajectories, and simulate charging behavior based on various trip attributes. The resulting ch...
Article
Limited charging infrastructure for electric vehicles (EVs) is one of the main barriers to adoption of these vehicles. In conjunction with limited battery range, the lack of charging infrastructure leads to range-anxiety, which may discourage many potential users. This problem is especially important for long-distance or intercity trips. Monthly tr...
Preprint
Full-text available
Electric vehicles (EVs) are considered as sustainable alternatives to conventional vehicles, as they reduce emission and fossil fuel dependency. A recent study has proposed a charging infrastructure planning tool to support intercity trips for the estimated EV market share (6 percent) in Michigan for 2030. The main goal of this study is to estimate...
Article
The range anxiety has been a major factor that affects the market acceptance of electric vehicles. Even with the recent development of battery technologies, a lack of charging stations and range anxiety are still significant concerns, specifically for intercity trips. This calls for more investments in building charging stations and advancing batte...
Article
Connected and automated vehicle technologies are expected to significantly contribute in improving mobility and safety. As connected and autonomous vehicles have not been used in practice at large scale, there are still some uncertainties in relation to their applications. Therefore, researchers utilize traffic simulation tools to model the presenc...
Technical Report
Full-text available
Snow removal and deicing activities are performed by roadway agencies to enhance winter mobility and safety. Due to slower travel speeds during these operations, low visibility and reduced pavement friction, safety and collision avoidance remain persistent concerns. To improve the visibility of winter maintenance vehicles, the Michigan Department o...
Article
Estimation of vehicular emissions at network level is a prominent issue in transportation planning and management of urban areas. For large networks, macroscopic emission models are preferred because of their simplicity. However, these models do not consider traffic flow dynamics that significantly affect emissions production. This study proposes a...
Article
Network travel time reliability can be represented by a relationship between network space-mean travel time and the standard deviation of network travel time. The primary objective of this paper is to improve estimation of the network travel time reliability with network partitioning. We partition a heterogeneous large-scale network into homogeneou...
Article
A network fundamental diagram (NFD) represents the relationship between network-wide average flow and average density. Network traffic state estimation to observe NFD when congestion is heterogeneously distributed, as a result of a time-varying and asymmetric demand matrix, is a challenging problem. Recent studies have formulated the NFD estimation...
Article
Path finding problem has a broad application in different fields of engineering. Travel time uncertainty is a critical factor affecting this problem and the route choice of transportation users. The major downside of the existing algorithms for the reliable path finding problem is their inefficiency in computational time. This study aims to develop...
Article
Winter maintenance trucks (WMTs) often operate at lower speeds during inclement weather and roadway conditions, creating potential safety issues for motorists following close behind. In this study, a new prototype radar-based rear-end collision avoidance and mitigation system (CAMS) was tested to assess its impact on the behavior of drivers followi...
Conference Paper
Network travel time reliability can be represented by a relationship between network space-mean travel time and the standard deviation of network travel time. The primary objective of this paper is to improve estimation of the network travel time reliability with network partitioning. We partition a heterogeneous large-scale network into homogeneou...
Technical Report
Snow removal and deicing activities are commonly performed by roadway agencies to enhance winter mobility and safety. Due to slower travel speeds during these operations, combined with low visibility and reduced pavement friction, the potential for rear- end collisions with winter maintenance trucks remains a persistent issue. A prototype collision...
Article
Background Estimation of vehicular emissions is one of the main challenges that planning agencies and municipalities encounter. This is particularly the case for large cities that typically struggle with congestion problems. Microscopic models are widely used to estimate the vehicular emissions. These models assist system planners in proposing stra...
Article
Network Fundamental Diagram (NFD) or Macroscopic Fundamental Diagram (MFD) represents dynamics of traffic flow at the network level. It is used to design various network-wide traffic control and pricing strategies to improve mobility and mitigate congestion. NFD is well defined when congestion distribution in the network is homogenous. However, in...
Presentation
Full-text available
Maintaining consistency between individuals’ activity choices and realistic network conditions is made possible through a unified framework of activity based and dynamic traffic assignment models. This presentation introduces a model of acitivity cancellation as part of broader hoursehol activity rescheduling in an integrated ADN-DTA model framewor...
Article
Full-text available
This paper presents a bi-level optimization problem to estimate offine time-dependent origin-destination (time-dependent O-D) demand on the basis of link flows and historical O-D matrices. The upper-level problem aimed to minimize the summation of errors in both traffic counts and O-D demand. Conventionally, O-D flows are linearly mapped to link fl...
Article
Full-text available
Maintaining consistency between individuals’ activity choices and realistic network conditions is made possible through a unified framework of activity-based and dynamic traffic assignment models. In this study, a model formulation and solution approach is presented for an integrated system of household activity schedule adjustment and multimodal d...
Article
Full-text available
The dynamic multimodal network assignment problem at the daily schedule level is addressed by integrating an activity-based model and a dynamic traffic assignment tool through a unified framework. The framework achieves this integration while retaining disaggregated individualized information. The problem is formulated as a fixed-point problem, and...
Article
Integrating activity-based models (ABMs) with simulation-based dynamic traffic assignment (DTA) have gained attention from transportation planning agencies seeking tools to address the arising planning challenges as well as transportation policies such as road pricing. Optimal paths with least generalized cost are needed to route travelers at the D...
Article
Full-text available
Applications of dynamic network equilibrium models have, mostly, considered the unit of traffic demand either as one-way trip, or as multiple independent trips. However, individuals’ travel patterns typically follow a sequence of trips chained together. In this study we aim at developing a general simulation-based dynamic network equilibrium algori...
Article
This paper proposes to optimally configure plug-in electric vehicle (PEV) charging infrastructure for supporting long-distance intercity travel using a general corridor model that aims to minimize a total system cost inclusive of infrastructure investment, battery cost and user cost. Compared to the previous work, the proposed model not only allows...
Article
High purchase prices and the lack of supporting infrastructure are major hurdles to the adoption of plug-in electric vehicles (PEVs). It is widely recognized that the government could help break these barriers through incentive policies, such as offering rebates to PEV buyers or funding charging stations. The objective of this paper is to propose a...
Article
Full-text available
This paper studies the path finding problem in stochastic networks with known travel time distributions on each link of the network, in the presence of spatial and temporal travel time correlations. As a result of traffic dynamics and the decisions of network users, distributions with different characteristics can be observed for the link travel ti...
Article
This study explores the limiting properties of network-wide traffic flow relations under heavily congested conditions in a large-scale complex urban street network; these limiting conditions are emulated in the context of dynamic traffic assignment (DTA) experiments on an actual large network. The primary objectives are to characterize gridlock and...
Article
This article studies the problem of locating fuel stations to minimize the extra cost spent in refueling detours, which belongs to a class of discretionary service facility location problems. Unlike many studies of similar problems in the literature, the proposed model considers capacity constraints and compares different ways to incorporate them i...
Article
Installing charging facilities in existing parking lots in city centers is considered an effective measure to encourage the adoption of plug-in electric vehicles (PEV). This paper is concerned with the problem of locating these facilities so as to minimize the total system cost. The problem is formulated as a fixed charge facility location model wi...
Article
Full-text available
To forecast the impact of congestion pricing schemes, it is essential to capture user responses to these schemes and the resulting dynamics of traffic flow on the network. The responses of users must include route, departure time, and mode choices. To capture the effects of these decisions, this paper lays out a framework for the integration of the...
Article
Full-text available
This paper evaluates different measurement methods of traffic flow variables taken at the network level. Generalized Edie’s definitions of fundamental traffic flow variables along highways are extended to consider vehicles traveling in networks. These definitions are used to characterize traffic flow in networks, and form the basis for estimating r...
Article
Full-text available
The aim of this study was to solve the minimum path travel time budget (MPTTB) problem, in which the travel time budget was the reliability index. This index was defined as the sum of the mean path travel time and the scaled standard deviation, which included the covariance matrix to consider correlation. Two existing solution methods in the litera...
Article
The main goal of the study was to integrate demand models into weather-responsive network traffic estimation and prediction system methodologies. The study examined the behavioral responses of travelers along several dimensions in response to weather-related transportation management strategies in conjunction with active travel demand management st...
Article
Full-text available
This paper explores some of the dynamics of urban network traffic flow during a large-scale evacuation in the context of the Network Fundamental Diagram (NFD). It is demonstrated that the structure of the evacuation demand can significantly affect network performance. A radial-shape structure resulted in a more stable network recovery compared to a...
Article
Full-text available
This paper provides a discussion of network traffic flow stability and network capacity including existing definitions and measurement methods in the literature. To characterize network traffic flow, three phases are defined as free flow (F), inhomogenously congested (IC), and homogenously congested. It is shown that in large non-homogenous network...
Conference Paper
This paper integrates real-time traveler information on prevailing traffic conditions (adaptive driving) into time-dependent origin-destination demand estimation in a simulation-based dynamic traffic assignment model. The objective is to explore the impact of adaptive driving on demand estimation, and to recognize a growing component of the traveli...
Conference Paper
Installing charging facilities in existing parking lots in city centers is considered an effective measure to encourage the adoption of plug-in electric vehicles (PEV). This paper is concerned with the problem of optimally locating these facilities to minimize the total system cost. The problem is formulated as a fixed charge facility location mode...
Article
Full-text available
This paper examines how correlations in link travel times affect reliable path finding in a stochastic network. The reliable path is defined as the path that requires the lowest travel time budget to ensure a given probability of on-time arrival. Such a path can be found by solving the shortest path problem considering on-time arrival reliability (...
Article
Full-text available
This study presents the development and application of methodologies to support weather-responsive traffic management (WRTM) strategies by building on traffic estimation and prediction system models. First, a systematic framework for implementing and evaluating WRTM strategies under severe weather conditions is developed. This framework includes ac...
Article
Full-text available
This study explores the limiting properties of network-wide traffic flow relations under heavily congested conditions in a large-scale complex urban street network; these limiting conditions are emulated in the context of dynamic traffic assignment (DTA) experiments on an actual large network. The primary objectives are to characterize gridlock and...
Article
Full-text available
The Transit Capacity and Quality of Service Manual (TCQSM) provides transit agencies with tools for measuring system performance at different levels of operation. Bus service reliability, one of the key performance measures, has become a major concern of both transit operators and users because it significantly affects user experience and service q...
Article
Full-text available
The focus of this study is on the aircraft routing problem and the potential role of a ferrying strategy for fueling the aircraft. The main contribution is to estimate the cost of maintenance routing when fuel ferrying strategies are considered. A combined model of aircraft routing and fuel management is developed and applied for three scenarios of...
Technical Report
Full-text available
The objective of the project is to develop a framework and procedures for implementing and evaluating weather-responsive traffic management (WRTM) strategies using Traffic Estimation and Prediction System (TrEPS) methodologies. In a previous Federal Highway Administration (FHWA) funded project, a methodology was developed and tested for incorporati...

Projects

Projects (4)
Project
This study takes a broad perspective on the characterization of travel time unreliability resulting from a variety of sources, and developing tools to incorporate reliability modeling in forecasting and evaluation tools.
Project
We examine fundamental flow relations and interactions (NFD's and other collective effects) at the network level, using a variety of data sources (sensors, probes) and simulation experiments to characterize phenomena such as flow breakdown, hysteresis and gridlock, and develop approaches to improve overall performance of traffic networks.
Project
We develop and test formulations for integrated ABM-DTA models and solution algorithms suitable for computation on large scale networks. Applications to demand forecasting, dynamic pricing and managed lanes are developed.