Authors: Minseok Kim, Hyeonmi Kim, Sungyoon Park and Saed Rahwanji
Conference: presentation at the 2014 TRB Alternative Intersections & Interchanges Symposium.
Unconventional Design: Six types of UIDs, including Superstreet (RCUT), CFI, CGT, DDI, SPUI, and DRI.
Purpose: presents the state of practice, case studies and analysis tools on unconventional designs in Maryland.
The Maryland State Highway Administration (MSHA) has been active in adopting unconventional design concepts at local intersections and interchanges as a feasible solution for relieving arterial congestion and improving safety. This paper presents the state of practice, case studies and analysis tools on unconventional designs in Maryland. The state of the practice focuses on six concepts consisting of restricted crossing u-turn (RCUT) intersection, continuous flow intersection (CFI), continuous green-T (CGT) intersection, diverging diamond interchange (DDI), single point urban interchange (SPUI), and double roundabout interchange (DRI). Case studies summarize the planning and design considerations that have been made for the first signalized RCUT intersection and DDI in the State of Maryland in addition to the 2nd CFI in Maryland. An overview of two analysis tools, developed as a joint research effort between MSHA and the University of Maryland at College Park, is also provided to introduce the Maryland Intersection Design & Capacity Analysis Program (MIDCAP) and Maryland Unconventional Intersection Designs (MUID) Analysis Tool. MIDCAP is useful to conduct capacity and queuing analyses based on the MSHA’s standard critical lane volume (CLV) and queuing methodology. MUID Analysis Tool contains statistical models to estimate the delay and queue in planning evaluations and models to optimize signal timings in operation analysis for three design concepts: 1) CFI, 2) DDI, and 3) signalized RCUT.
This presentation is for Master’s thesis defence of Liu Xu on May 3rd, 2016.
Author: Yao Cheng
Type: Master Defense
Author: Xianfeng Yang
Type: PhD Defense
Author: Woon Kim
Type: PhD Defense
Author: Nan Zou
Type: MS Thesis
Abstract: This study presents a network simulator that integrates the knowledge base with a microscopic traffic simulation model for real-time traffic management. The proposed system offers three main functions: incident management, work-zone operations and recurrent congestion monitoring. The knowledge base is used to inventory the operational experience and traffic impacts associated with all previously recorded incidents. Such information will be used along with an embedded prediction module to estimate the duration of a detected incident.The proposed system will enable traffic control operators to perform two critical tasks
during the incident management period: (1) establishing a reliable estimate of traffic impacts; and (2) performing a subsequent real-time analysis of network traffic conditions. The simulation results will also offer information for estimating travel time at varying departure times for different origins and destinations during the period of incident operations.
Author: Xin Zhang
Type: PhD Dissertation
Abstract: In most metropolitan areas, an emergency evacuation may demand a potentially large number of evacuees to use transit systems or to walk over some distance to access their passenger cars. In the process of approaching designated pick-up points for evacuation, the massive number of pedestrians often incurs tremendous burden to vehicles in the roadway network. Hence, one critical issue in a multi-modal evacuation planning is the effective coordination of the vehicle and pedestrian flows by considering their complex interactions. The purpose of this research is to develop an integrated system that is capable of generating the optimal evacuation plan and reflecting the real-world network traffic conditions caused by the conflicts of these two types of flows.The first part of this research is an integer programming model designed to optimize the control plans for massive mixed pedestrian-vehicle flows within the evacuation zone. The proposed model, integrating the pedestrian and vehicle networks, can effectively account for their potential conflicts during the evacuation. The model can generate the optimal routing strategies to guide evacuees moving toward either their pick-up locations or parking areas and can also produce a responsive plan to accommodate the massive pedestrian movements
Author: Ying Liu
Type: PhD Dissertation
Abstract: How to effectively control evacuation traffic has emerged as one of the critical research issues in transportation community, due to the unusually high demand surge and the often limited network capacity. This dissertation has developed an integrated traffic control system for evacuation operations that may require concurrent implementation of different control options, including traffic routing, contraflow operation, staged evacuation, and intersection signal control. The system applies a hierarchical control framework to achieve a trade-off between modeling accuracy and operational efficiency for large-scale network applications. The network-level optimization formulations function to assign traffic to different evacuation corridors, select lane reversal configurations for contraflow operations, and identify the evacuation sequence of different demand zones for staged evacuation. With special constraints to approximate flow interactions at intersections, the formulations have introduced two network enhancement approaches with the aim to capture the real-world operational complexities associated with contraflow operations and staged evacuation.
Author: Kyeong-Pyo Kang
Type: PhD Dissertation
Abstract: 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. This study is focused on developing an advanced dynamic merge and variable speed limit controls for work zone applications, including an integration of both controls for best use of their strengths in maximizing throughputs and minimizing speed variance in traffic flows. With respect to the merge control, this study has developed an advanced dynamic late merge (DLM) control model and its operation algorithm, based on the optimized control thresholds that take into account the interactions between the speed, flow, and available work zone capacity. The proposed DLM control allows potential users to select the control variables and to determine their optimal thresholds in response to traffic flow dynamics. Evaluation results with extensive simulation experiments have shown that the work zone highway segment with the proposed DLM can effectively respond to time-varying traffic conditions and yield more work-zone throughputs than that under the existing DLM control based on the static control threshold, and also result in an increase in the average speed and decrease in the speed variation.