Highway Capacity Manual改訂の動向--テイラ-教授の講演より

A challenging application of artificial intelligence systems involves the scheduling of traffic signals in multi-intersection vehicular networks. This paper introduces a novel use of a multi-agent system and reinforcement learning (RL) framework to obtain an efficient traffic signal control policy. The latter is aimed at minimising the average delay, congestion and likelihood of intersection cross-blocking. A five-intersection traffic network has been studied in which each intersection is governed by an autonomous intelligent agent. Two types of agents, a central agent and an outbound agent, were employed. The outbound agents schedule traffic signals by following the longest-queue-first (LQF) algorithm, which has been proved to guarantee stability and fairness, and collaborate with the central agent by providing it local traffic statistics. The central agent learns a value function driven by its local and neighbours' traffic conditions. The novel methodology proposed here utilises the Q-Learning algorithm with a feedforward neural network for value function approximation. Experimental results clearly demonstrate the advantages of multi-agent RL-based control over LQF governed isolated single-intersection control, thus paving the way for efficient distributed traffic signal control in complex settings.

Reinforcement learning-based multi-agent system for network traffic signal control

Network Robustness Index : a new method for identifying critical links and evaluating the performance of transportation networks

This paper presents a review of highway-based evacuation modeling and simulation and its evolution over the past decade. The review includes the major components of roadway transportation planning and operations, including the current state of modeling in the forecasting of evacuation travel demand, distribution and assignment of evacuation demand to regional road networks to reach destinations, assignment of evacuees to various modes of transportation, and evaluation and testing of alternative management strategies to increase capacity of evacuation networks or manage demand. Although this discussion does not cover recent work in other modes used in evacuation such as air, rail, and pedestrian, this paper does highlight recent interdisciplinary modeling work in evacuation to help bridge the gap between the behavioral sciences and engineering and the application of emerging techniques for the verification, validation, and calibration of models. The manuscript also calls attention to special considerations and logistical difficulties, which have received limited attention to date. In addition to these concerns, the following future directions are discussed: further interdisciplinary efforts, including incorporating the medical community; using new technologies for communication of warnings and traffic condition information, data collection, and increased modeling resolution and confidence; using real-time information; and further model refinements and validation.

Evacuation transportation modeling: An overview of research, development, and practice

Travel time reliability is a fundamental factor in travel behavior. It represents the temporal uncertainty experienced by users in their movement between any two nodes in a network. The importance of the time reliability depends on the penalties incurred by the users. In road networks, travelers consider the existence of a trip travel time uncertainty in different choice situations (departure time, route, mode, and others). In this paper, a systematic review of the current state of research in travel time reliability, and more explicitly in the value of travel time reliability is presented. Moreover, a meta-analysis is performed in order to determine the reasons behind the discrepancy among the reliability estimates.

Value of Travel Time Reliability: A Review of Current Evidence

The events of recent hurricane seasons have made evacuation a leading emergency management issue In 1998 and 1999, Hurricanes Georges and Floyd precipitated the two largest evacuations in the history of the United States and perhaps, its two largest traffic jams In response to the problems experienced during these events, many state departments' of transportation have begun to take a more active role in the planning, management, and operation of hurricane evacuations This is somewhat of a departure from prior practice when emergency management officials directed these tasks almost exclusively Since the involvement of transportation professionals in the field of evacuation has been a fairly recent development, many of the newest practices and policies have only been used once, if ever They also vary widely from state-to-state To determine what the latest policies and strategies are and how they differed from one location to another, a national review of evacuation plans and practices was recently undertaken The study was carried out from a transportation perspective and included both a review of the traditional transportation literature and a survey of department of transportation and emergency management officials in coastal states threatened by hurricanes This paper highlights the findings of the survey portion of the study It focuses mainly on current state practices, including the use of reverse flow operations and intelligent transportation systems It also summarizes current evacuation management policies, methods of information exchange, and decision-making criteria This paper presents the general similarities and differences in practices and gives particular attention to unique, innovative, and potentially useful practices used in individual states

National review of hurricane evacuation plans and policies: a comparison and contrast of state practices

Although evacuation planning and operations have long been topics of critical significance to the hazards preparedness and response community, only in the past several years have they emerged to become important issues among transportation professionals. The increased level of interest has been the result of several recent high-profile evacuations and the realization that, in the wake of the September 11 terrorist attacks, the potential need to rapidly evacuate large populations is perhaps greater than it has ever been. This paper is the first in a two-part series that reviews transportation engineering aspects of hurricane evacuations, addressing policies and practices for transportation system planning, preparedness, and response. (Part II focuses on traffic operations, management, and control.) Results of a survey of state evacuation practices are presented, including command and control strategies, types of evacuations used, and implementation and enforcement criteria. Evacuation modeling methods are reviewed and recent transportation community initiatives are discussed. Although this study focused primarily on issues pertaining to hurricane evacuations, many of the findings are also applicable to multihazard evacuation planning and operations.

Review of Policies and Practices for Hurricane Evacuation. I: Transportation Planning, Preparedness, and Response

Over the past 20 years, the coastal population of the southeastern United States that is vulnerable to hurricanes has increased significantly Much of the recent planning and construction of infrastructure in these regions has taken place during a two-decade lull in hurricane activity It is now apparent that these areas are not all suitably equipped to deal with the threat of severe hurricanes As a result, a significant percentage of the coastal population is forced to evacuate under the threat of major hurricanes This has been demonstrated recently during Hurricane Floyd in 1999 and during Hurricane Georges in 1998 One method suggested to meet the need to evacuate large numbers of people in a rapid and efficient manner is to contraflow segments of interstate freeway Under contraflow operation, some or all inbound lanes of a freeway are used for outbound evacuation While the concept is simple, implementation is complex This paper discusses the advantages and disadvantages of contraflow operation on freeways during hurricane evacuations, including the capacity benefits, critical planning, design, and operational issues, and current contraflow operation plans from threatened states The paper also provides a list of recommendations and needs that should be considered in the planning and implementation of contraflow evacuations

"One-way-out": contraflow freeway operation for hurricane evacuation

The city of New Orleans is among the most vulnerable cities in the world to the threat of hurricanes. To protect its population from these storms, officials in Louisiana have joined a growing number of states that are planning to use contraflow freeway operations to expedite the evacuation of threatened areas. Although contraflow is widely regarded as a major advance in evacuation planning and response, no one really knows how well, or even if, it will work. Research was undertaken to improve the understanding of traffic conditions on contraflow freeway segments during an evacuation. The CORSIM microscopic traffic-simulation program was used to model the freeway configuration that will be used to evacuate New Orleans as well as two alternative scenarios for this same segment. The results showed that the currently proposed configuration might result in an underutilization of the contraflow segment, thus significantly limiting the number of evacuees who can get out of the city. The study also showed how the effectiveness of the New Orleans contraflow segment might be significantly improved with some simple and inexpensive modifications to the existing plan. Most important, the results of the research underscore the critical nature of proper planning and design of contraflow entry points and how they are often overlooked for both emergency and nonemergency conditions.

Brian Wolshon

Papers

Evacuation transportation modeling: An overview of research, development, and practice

National review of hurricane evacuation plans and policies: a comparison and contrast of state practices

Review of Policies and Practices for Hurricane Evacuation. I: Transportation Planning, Preparedness, and Response

"One-way-out": contraflow freeway operation for hurricane evacuation

Alternative Methods to Increase the Effectiveness of Freeway Contraflow Evacuation