Development of Optimal Control Strategies for Freeway Work Zone Operations

To improve traffic mobility and safety on highway segments plagued by work zone activities, transportation professionals in recent years have focused on exploring the potentials of using various merge and speed control strategies to regulate traffic flows…


Chapter 1 Introduction
1.1 Background
1.2 Research Objectives and Scope
1.3 Organization of Dissertation
Chapter 2 Literature Review
2.1 Introduction
2.2 Merge controls
2.2.1 NDOR merge (Nebraska Department of Roads) control
2.2.2 Static early merge (SEM) control
2.2.3 Dynamic early merge (DEM) control
2.2.4 Static late merge (SLM) control
2.2.5 Dynamic late merge (DLM) control
2.2.6 Other supplementary merge devices
2.3 Speed controls
2.3.1 Posted speed limit (PSL) control
2.3.2 Speed monitoring display (SMD) and Speed advisory sign (SAS) control
2.3.3 Variable speed limit (VSL) control
2.3.4 Other supplementary strategies
2.4 Closure
Chapter 3 Investigating Macroscopic Traffic Flow Properties in Highway Work Zones
3.1 Introduction
3.2 Description of field data collection
3.3 Density estimation from the field data
3.3.1 Procedures for the density estimation
3.3.2 Mesoscopic prediction model for the speed-density relation
3.3.3 Estimation procedures
3.3.4 Evaluation of the proposed estimation procedures
3.4 Macroscopic traffic flow properties
3.4.1 Non work-zone (stationary) traffic condition
3.4.2 Work-zone (non-stationary) traffic condition
3.5 Conclusions
Chapter 4 Development of An Advanced Dynamic late Merge Contorl Model and Algorithm
4.1 Overview of merge control strategies
4.2 Methodology for the DLM control model
4.2.1 Investigation on SEM and SLM controls
4.2.2 Concept of the optimal control thresholds
4.2.3 Key variables and parameters
4.2.4 Optimal control thresholds and DLM operational logic
4.3 Model descriptions for the optimal control thresholds
4.3.1 Model components
4.3.2 Calculation of input variables for work-zone traffic flow equations
4.3.3 Estimation of lane-changing parameter
4.3.4 Equation for traffic flow equilibrium condition
4.3.5 Equation for maximum flow rate (MFR)
4.3.6 Equation for moderate flow rate (MOD)
4.3.7 Equation for the optimal merging capacity (OMC)
4.3.8 Model formulation
4.4 Performance of the DLM control using the optimal control threshold
4.4.1 Checking the traffic state-dependent control threshold
4.4.2 Performance of the optimized time-varying control threshold
4.5 Conclusions
Chapter 5 : Development of Optimal variable Speed Limit Control Model and Operation Algorithm
5.1 Introduction
5.2 VSL System Description
5.3 Methodology for VSL Control Model
5.4 VSL Control Algorithm
5.5 Model Evaluation with Simulation Experiments
5.5.1 Design of simulated system
5.5.2 Simulation of the on-line control process
5.5.3 Trends of optimal VSL
5.5.4 Sensitivity analysis
5.5.5 Evaluation of the VSL control model performance
5.6 Summary
Chapter 6 Integrated Control Algorithm of The DLM and VSL Control Strategies
6.1 Introduction
6.2 Critical issues for integration
6.3 Development of the integrated algorithm
6.4 Evaluation of the integrated control
6.4.1 Design of experiments
6.4.2 Performance evaluation
6.5 Summary
Chapter 7 Conclusions and Recommendations
7.1 Summary of Research Accomplishments
7.2 Conclusions and Recommendations

Author: Kang, Kyeong-Pyo

Source: University of Maryland

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