Traffic Operations and Management

Are the Objectives and Solutions of Dynamic User-Equilibrium Models Always Consistent?

Lin, Wei-Hua
Lo, Hong
1996

Traffic assignment models are an important component in analyzing the relationship between demand and supply in the transportation network for design, planning, and control purposes. The static traffic assignment model has been used in practice for several decades. With the latest development in the area of Advanced Traffic Management Systems (ATMS) and Advanced Traveler Information Systems (ATIS), there is an increasing demand for dynamic traffic assignment models to serve as a basis for studying various issues in these areas.Existing dynamic user-equilibrium traffic assignment (DUETA)...

Study of Freeway Traffic Near an Off-Ramp

Cassidy, Michael J.
Anani, Shadi B.
Haigwood, John M.
2000

A bottleneck with a diminished capacity is shown to have arisen on a freeway segment whenever queues from the segment's off-ramped spilled over and occupied its mandatory exit lane. It is also shown that longer exit queues from the over-saturate off-ramp were accompanied by lower discharge rates for non-exiting vehicles. The explanation appears to be rubber-necking on the part of the non-exiting drivers. Whenever the of-ramp queues were prevented from spilling over to the exit lane (by changing the logic of a nearby traffic signal), much higher flows were sustained on the freeway segment...

Models Of Commuters' Information Use And Route Choice: Initial Results Based On A Southern California Commuter Route Choice Survey

Abdel-aty, Mohamed A.
Vaughn, Kenneth M.
Kitamura, Ryuichi
Jovanis, Paul P.
Mannering, Fred L.
1993

This paper presents a statistical analysis of commuters' route choice behavior and the influence of traffic information. The analysis is based on a 1992 computer-aided telephone interview survey of Los Angeles area morning commuters. The results underscore the important relationship between the use of traffic information and the propensity to change routes. In addition, important relationships are uncovered relating the influence that commuters' socioeconomic characteristics and the level of traffic congestion they face have on traffic information use and route- change frequency. The...

Intermodal Transportation Operation System ( ITOS ) For The State Of California

Hall, Randolph
Parekh, Chethan
Thakker, Viral
1998

Intermodal transportation entails the coordinated movement of different types of transportation (rail, truck, automobile, etc.) to serve the needs of travelers and shippers. The purpose of this report is to provide a vision for systems to coordinate intermodal operations in California in the future, and also to document the types of systems that are being used today in a range of transportation modes. An intermodal system could, conceivably, establish a center (or centers) that is responsible for the joint operation of multiple modes of transportation. This is not our preferred vision....

Trav Info Evaluation ( Technology Element ) Traveler Information Center ( TIC ) Study: Operator Interface Analysis - Phase III

Miller, Mark
Loukakos, Dimitri
1998

TravInfo is a Field Operational Test of advanced traveler information systems for the San Francisco Bay Area, sponsored by the Federal Highway Administration (FHWA). The project involves a public/private partnership which seeks to compile, integrate and broadly disseminate timely and accurate multi-modal traveler information through commercial products and services. The public sector component centers on the Traveler Information Center (TIC), which collects and integrates both static and dynamic traveler information. The TIC began operations in September 1996 and will operate as an FOT...

Using Technology to Improve Transportation Services

Garrison, William L.
1988

Today's transportation systems are well deployed in the developed nations, and they and their supporting activities are technologically and institutionally mature. This situation is exceptional in the perspective of the last 200 years of transportation development, during which new systems were innovated and wave after wave of construction undertaken.An examination of the ways technologies were shaped and adopted in the past reveals that today's view of technology-based opportunities is also exceptional. Consistent with system maturity, the search for improvements is focused on marginal...

An Analytical Dynamic Traffic Assignment Model with Probabilistic Travel Times and Travelers' Perceptions

Liu, Henry X.
Ban, Xuegang
Ran, Bin
Mirchandani, Pitu
2002

Dynamic traffic assignment (DTA) has been a topic of substantial research during the past decade. While DTA is gradually maturing, many aspects of DTA still need improvements, especially regarding its formulation and solution capabilities under the transportation environment impacted by the Advanced Transportation Management and Information Systems (ATMIS). It is necessary to develop a set of DTA models to acknowledge the fact that the traffic network itself is probabilistic and uncertain, and different classes of travelers respond differently under uncertain environment, given different...

Robust Multiple Car Tracking With Occlusion Reasoning

Koler, Dieter
Weber, Joseph
Malik, Jitendra
1994

In this paper, the authors address the problem of traffic surveillance in an Advanced Transportation Management System. They propose a new approach for detecting and tracking vehicles in road traffic scenes that attains a level of accuracy and reliability which lies beyond currently available systems. High accuracy and reliability are obtained by using an explicit occlusion reasoning step, employing a contour tracker based on intensity and motion boundaries.

Validation of the Incremental Transfer Model

Robert, Tim
Lin, Wei-Hua
Cassidy, Michael
1999

This report documents our validation effort on the Incremental Transfer (IT) model, which is a macroscopic traffic flow model capable of handling freeway systems with special lanes and priority vehicles. The validation study is performed with field data from a 1.7-mile long freeway segment with a congested off-ramp in Oakland, California. In our study, vehicles exiting the off- ramp of this segment are treated as "regular vehicles" and through vehicles as "special vehicles." By assuming that the exiting or "regular" vehicles must stay on the "near" side lanes, we examine the spatial...

Personalized Demand Responsive Transit Systems

Yim, Y. B.
Khattak, Asad J.
2000

An aging population in the US, low-density urban sprawl and the accessibility needs of certain groups (particularly disabled and aged) increasingly point to more flexible demand-responsive transit systems in the future. This paper describes the important aspects of a consumer-oriented Personalized Demand Responsive Transit (PDRT) service. The system will provide services to the traveling public for journeys to work and for journeys to other destinations. A PDRT that responds to the travelers' needs and takes advantage of the emerging advanced public transportation technologies to increase...