Traffic Operations and Management

Development of BRT Architecture: A System Engineering Approach

Hickman, Mark
Tan, Chin-Woo
Lau, Peter
Zhang, Wei-Bin
2006

This report discusses the development of system architecture for Intelligent Transportation Systems (ITS) applications for Bus Rapid Transit (BRT) systems. In the course of the development of system architecture, it is critical to take a system engineering approach in the development of BRT architecture to assess BRT service needs (or features), the functional realization of these service needs and the means of technological implementation. Motivated by the National ITS architecture, the BRT architecture has a hierarchy of three layers: application, physical, and logical. The application...

Simulation of IVHS on the Santa Monica Freeway Corridor Using the INTEGRATION Model. Phase 2: Preliminary ATIS and ATMS Experiments

Gardes, Yonnel
May, Adolf D.
1993

The general objective of the project is to investigate and quantify the likely benefits of implementing various ATMS and ATlS control strategies on the real-life Santa Monica freeway corridor in Los Angeles.The different strategies to be tested in Phase 2 include freeway ramp metering, real-time traffic signal optimization, route guidance systems, and combinations of these strategies. Investigations of different strategies are performed for the same network conditions (portion of the Santa Monica freeway corridor previously coded in Phase 1) and under the same demand level (typical morning...

Trav Info Evaluation Traveler Response Element: Trav Info 817-1717 Caller Study Phase 1 Results

Yim, Youngbin
Hall, Randoph
Koo, Ronald
Miller, Mark A.
1998

This paper presents a discussion on how traffic information is obtained and how the congestion of a major freeway affects travel behavior. It reports on survey results of commuters affected by two highway incidents south of San Francisco. The survey collected information on travel behavior, how the traffic information was obtained, and how it influenced route, model of travel and departure time. Results of the surveys suggest that travel behavior is largely unaffected by individual incidents of congestion. The study is also one of several designed to provide an assessment of the impact of...

Identifying the Onset of Congestion Rapidly with Existing Traffic Detectors

Coifman, Benjamin
1999

From an operations standpoint, the most important task of a traffic surveillance system is determining reliably whether the facility is free flowing or congested. The second most important task is responding rapidly when the facility becomes congested. Other tasks, such as quantifying the magnitude of congestion, are desirable, but tertiary. To address the first two tasks, this paper presents a new approach for traffic surveillance using existing detectors. Rather than expending a considerable effort to detect congested conditions, the research employs a relatively simple strategy to look...

The Cell Transmission Model: Network Traffic

Daganzo, Carlos
1994

This paper shows how the evolution of multicommodity traffic flows over complex networks can be predicted over time, based on a simple macroscopic computer representation of traffic flow that is consistent with the kinematic wave theory under all traffic conditions. After a brief review of the basic model for one link, the paper describes how three-legged junctions can be modeled. It then introduces a numerical procedure for networks, assuming that a time-varying origin-destination table is given and that the proportion of turns at every junction is known. These assumptions are reasonable...

On-line Traffic Signal Control Scheme with Real-time Delay Estimation Technology

Liu, Henry X.
Oh, Jun S.
Oh, Seri
Chu, Liany
Recker, Will
2001

This paper presents an on-line signal control scheme integrated with the real-time intersection delay estimation technology. The primary goal of this study is to design a complementary optimization module to the existing controller to minimize the total delay experienced by traffic and improve the system performance at the signalized intersections. This paper proposes a feedback control algorithm that optimizes the signal timing plan based on delay estimated via vehicle re-identification technology. Main thrust of the algorithm is on-line control capability utilizing direct delay measures...

Using Vehicles Equipped with Toll Tags as Probes for Providing Travel Times

John, Wright
Dahlgren, Joy
2001

The introduction of electronic toll collection on the eight bridges crossing San Francisco Bay has provided the means for a relatively simple and low cost system for measuring travel times on many Bay Area bridges and roads. The toll tags sued for electronic toll collection can be read by readers at various locations on congested roads. The time of reading is recorded so that the time difference between when a vehicle passes one reader and passes the next can be computed. Such a system is already operating in Houston, where it is the primary source of travel time data. Capital costs per...

Orange County Transit Probe Evaluation: Phase I Institutional Findings

Hall, Randolph W.
1997

This report documents the institutional issues that have faced the Orange County probe project, a multi-agency project designed to equip a fleet of buses with Global Positioning System (GPS) based tracking equipment and to use tracking data for multiple purposes. The usefulness of the data involve: 1) bus schedule adherence and fleet management; 2) collection of information on roadway traffic congestion; and, 3) dissemination of transit data to patrons.

Travel Time Estimation on the San Francisco Bay Area Network Using Cellular Phones as Probes

Ygnace, Jean-Luc
Drane, Chris
Yim, Y. B.
de Lacvivier, Renaud
2000

Current traffic travel time estimates are largely based on road sensors embedded in the pavement. Today technical developments in cellular positioning and the spread of wireless phones provide the opportunity to track cell phone equipped drivers as traffic probes. The Federal Communication Commission Phase II mandate for Enhanced-911 (E-911) requires that wireless carriers must provide the location of a 911 wireless call by October 1, 2001 to the Public Safety Answering Point (PSAP), within approximately 125 meters, or under one-tenth of a mile in the majority of situations. The motivation...

Effect of Longitudinal Control on Capacity

Beji, Yousser
1987

This paper focuses on what benefits a longitudinal control system can be expected to render to the present highway system.There are three major reasons why longitudinal control should be expected to improve traffic flow and to reduce accidents.(1) It may permit higher traffic densities with uniform spacing forming an even distribution with increased travel speeds and consequently higher capacity.(2) It may reduce the rate of rear-end collisions that occur on urban freeways.(3) It can provide increased stability in traffic flow (shockwaves due to human response characteristics are the main...