Jeffrey L. Adler

Cellular automata microsimulation for modeling bi-directional pedestrian walkways

Pedestrian flow is inherently complex, more so than vehicular flow, and development of microscopic models of pedestrian flow has been a daunting task for researchers. This paper presents the use of Cellular automata (CA) microsimulation for modeling bi-directional pedestrian walkways. It is shown that a small rule set is capable of effectively capturing the behaviors of pedestrians at the micro-level while attaining realistic macro-level activity. The model provides for simulating three modes of bi-directional pedestrian flow: (a) flows in directionally separated lanes, (b) interspersed flow, and (c) dynamic multi-lane (DML) flow. The emergent behavior that arises from the model, termed CA-Ped, is consistent with well-established fundamental properties.

Emergent fundamental pedestrian flows from cellular automata microsimulation

In recent years cellular automata (CA) have been successfully applied to modeling traffic flow. Use of a CA for modeling pedestrian flows is examined here. A particle hopping model for a single-directional pedestrian flow over a multilane walkway is presented. This model offers the advantage of effectively capturing the behaviors of pedestrians at the micro-level while attaining realistic macro-level activity. The emergent group behavior is an outgrowth of the interaction of the rule set in simulation. The results indicate that a heuristically derived minimal rule set produces flow patterns that closely resemble the accepted fundamental diagrams. Important parameters for determining the shape of the fundamental diagrams are examined. Key rules used in a vehicular traffic CA are tested for their applicability to the pedestrian CA model.

TOWARD THE DESIGN OF INTELLIGENT TRAVELER INFORMATION SYSTEMS

The emergence of Intelligent Transportation Systems (ITS) has fostered the development of advanced traveler information systems (ATIS). These systems are designed to assist travelers in making pre-trip and enroute travel choice decisions. It is contended that while many traveler information systems are innovative and make use of cutting edge technologies, they lack real machine intelligence and therefore may be limited in their ability to service the traveling public over the long-run. The purpose of this paper is to present a vision of the next generation traveler information system, termed Intelligent Traveler Information Systems (ITIS) in which artificial intelligence techniques are drawn upon to create systems capable of providing travelers with more personalized planning assistance.

CELLULAR AUTOMATA MICROSIMULATION OF BIDIRECTIONAL PEDESTRIAN FLOWS

The cellular automata (CA) microsimulation of pedestrians is a particlehopping model in which a set of local rules prescribe the behavior of entities within local neighborhoods of cells. CA microsimulation has emerged as a tool for simulating traffic flow and modeling transportation networks. Pedestrian flow is inherently more complex than vehicular flow, and simulation models that are used for emulating vehicular traffic are not directly applicable to modeling pedestrian movements. In previous work the authors demonstrated that unidirectional pedestrian flow patterns consistent with well-established fundamental properties could be generated with CA microsimulation. This paper expands upon the previous effort and presents a CA microsimulation model and emergent fundamental flows for a bidirectional pedestrian walkway. Simulation experiments indicate that the basic model is applicable to walkways of various lengths and widths and across different directional shares of pedestrian movements.

Investigating the learning effects of route guidance and traffic advisories on route choice behavior

Abstract This paper describes a study to investigate the effects of route guidance and traffic advisories on drivers route choice behavior. The study is a two-factor experiment with repeated measures on one factor where the between-subjects factor is the type of traveler information provided and the repeated, within-subjects factor is trips made between a specified origin and destination. Participants were recruited and randomly assigned to one of four groups: group 1 having only a basic map of the network; group 2 having access only to route guidance, group 3 having access to traffic advisory information, and group 4 having access to both route guidance and traffic advisory information. Each participant completed 15 trips between a specified origin-destination pair on a hypothetical network. The results of this study indicate that there may be significant short-term advantages to providing in-vehicle routing and navigation information to unfamiliar drivers. However, the results also indicate that the format and amount of information provided may not be significant as the benefits to having route guidance diminish when drivers become more familiar with the travel network.

Modeling Four-Directional Pedestrian Flows

The objective of this study is to explore the modeling of multidirectional pedestrian flows. The complex interactions between flow entities within m-directional space present challenges that cannot be readily handled by existing bidirectional flow models. A cellular automata microsimulation model for four-directional flow is prescribed. This model, built on previous bidirectional models developed by the authors, additionally seeks to manage cross-directional conflicts. Performance of this function in the simulation of unidirectional, bidirectional, cross-directional, and four-directional flows is presented. The applications extend to m-directional terminal facility design and to four-directional street corners, a vital component in any network model of pedestrians.

In-Laboratory Experiments to Investigate Driver Behavior under Advanced Traveler Information Systems (ATIS)

In-laboratory experimentation with interactive microcomputer simulation is a useful tool for studying the dynamics of driver behavior in response to advanced traveler information systems. Limited real-world implementation of these information systems has made it difficult to observe and study how drivers seek, acquire, process, and respond to real-time information. This paper describes the design and preliminary testing of an interactive microcomputer-based animated simulator, developed at the University of California, Irvine, to model pre-trip and enroute driver travel choices in the presence of advanced traveler information systems. The advantages of this simulator are realized in its versatility to model driver decision processing while presenting a realistic representation of the travel choice domain. Results from a case study revealed that increased driver familiarity with travel conditions and network layout reduces driver reliance on information systems and influences drivers diversion behavior.

A direct redistribution model of congestion pricing

This paper discusses a direct redistribution approach to congestion pricing in which monies collected from drivers on a more desirable route are directly transferred to users on a less desirable route. An analytical model for a two-node two-route network is developed. An example is used to demonstrate the applicability of this model. It is shown that this model of toll collection and subsidization will reduce the travel cost for all travelers and totally eliminate the waiting time in the queue. When compared against the social optimal assignment, the direct redistribution model yields almost identical results.

Real-Time Multiple-Objective Path Search for In-Vehicle Route Guidance Systems

The application of multiple-objective route choice for in-vehicle route guidance systems is discussed. A bi-objective path search algorithm is presented and its use demonstrated. A concept of trip quality is introduced that is composed of two objectives: minimizing travel time and minimizing trip complexity. Trade-offs between the objectives are examined. The concept is illustrated through simulation modeling on a test network. The experiments serve to demonstrate the effects on the trip performance of pretrip routing and dynamic routing strategies under full market penetration (an idealized condition) and under varying levels of demand and trade-offs between time and complexity.

Advanced educational tools for Intelligent Transportation Systems training

With the rapid development and deployment of Intelligent Transportation Systems, there has emerged a significant need for professional development for transportation professionals. Innovations in educational technology provide new ways to deliver on-demand training. Research is underway at Rensselaer, sponsored by the Federal Highway Administration, to explore the development and application of interactive multimedia educational tools for Intelligent Transportation Systems training. This paper provides an overview of the project and describe two educational aids being developed, an interactive multimedia handbook on wireless communications and a computer-based game on designing and deploying Electronic Toll Collections Systems.