Traffic Operations and Management

The Design of a Controller for a Following Vehicle in an Emergency Lane Change Maneuver

Swaroop, D.
Yoon, Seok Min
1999

A lane change maneuver is one of the many appropriate responses to an emergency situation. The design of an Emergency Lane Change (ELC) maneu- ver for a platoon of two vehicles is considered in this paper. In response to the presence of a stationary or a slowly moving obstacle in the lane or any such emergency, the lead vehicle in the platoon designs an ELC trajectory on-line and broadcasts the trajectory curvature information in real time to its follower. The problem considered, in this paper, is the design of an integrated lateral and longitudinal controller that enables the follower to...

Safety Aspects of Freeway Weaving Sections

Golob, Thomas F.
Recker, Wilfred W.
Alvarez, Veronica M.
2003

One source of vehicle conflict is the freeway weaving section, where a merge and diverge in close proximity require vehicles either entering or exiting the freeway to execute one or more lane changes. Using accident data for a portion of Southern California, we examined accidents that occurred on three types of weaving sections defined in traffic engineering: Type A, where every merging or diverging vehicle must execute one lane change, Type B, where either merging or diverging can be done without changing lanes, and Type C, where one maneuver requires at least two lane changes. We found...

The Effects of Data Inaccuracy on the Performance of Traffic Signal Timing Plans

Lin, Wei-Hua
Liao, Lawrence C.
1998

This paper explores the performance of signal timing plans calibrated with perfect or imperfect information. The arrival information considered include arrival rates and arrival distributions. The study is conducted for different levels of arrival rates and different forms of arrival distributions under a wide range of arrival information inaccuracy, traffic intensity, and intersections with balanced and unbalanced flows.Our results indicate that the increase in delay, the number of stops, and queue length is in general insignificant when the arrival distribution used to calibrate the...

Path ATMIS/Systems State of the Research: Annual Report Fiscal Year 1997/1998

Tam, Robert
1998

This report presents a summary of California PATH Advanced Traffic Management and Traffic Information Systems (ATMIS) and Systems research for FY 1997-1998. For each project, a brief description is given of the objectives, status outline, and principal results. The report is organized into the following research topics: Surveillance Systems, Traffic Management Systems, Traffic Modeling, Traveler Information Systems, Public Transportation Systems, and System Integration and Benefit/Cost Analysis.

A Tool to Evaluate the Safety Effects of Changes in Freeway Traffic Flow

Golob, Thomas F.
Recker, Wilfred W.
Alvarez, Veronica M.
2003

This research involves the development of a tool that can be used to assess the changes in traffic safety tendencies that result from changes in traffic flow. The tool uses data from single inductive loop detectors, converting 30-second observations of volume and occupancy for multiple freeway lanes into traffic flow regimes. Each regime has a specific pattern of crash types, which were determined through nonlinear multivariate analyses of over 1,000 crashes on freeways in Southern California. These analyses revealed ways in which differences in variances in speeds and volumes across lanes...

Evaluation of On-ramp Control Algorithms

Zhang, Michael
Kim, Taewan
Nie, Xiaojian
Jin, Wenlong
Chu, Lianyu
Recker, Will
2001

The control of a traffic corridor, which consists of two major component - freeway system control and arterial street system control, aims to improve flows on both freeway and arterial streets, and has been demonstrated as an effective means to increase the level of service of a corridor system during peak periods. Ramp metering, or ramp control, has been considered to be a very important component of corridor traffic control. Ramp metering is the application of control devices such as metering signals to limit the number of vehicles entering a freeway. The fundamental philosophy of ramp...

Commuter Response To Traffic Information On An Incident

Koo, Ronald
Yim, Youngbin
1998

This paper presents and discusses how traffic information is obtained and how it affects travel behavior when a major freeway is congested. Immediately following a major highway incident south of San Francisco which caused congestion, a telephone survey was conducted of commuters who utilize the affected corridor of highway. The behavior of commuters before and during their commute at the time of the incident was determined, including obtaining traffic information and how the information influenced changes in route, mode of travel and departure time. The results of the survey suggest that...

Variable Message Signs and Link Flow Evaluation: A Case Study of the Paris Region

Yim, Youngbin
Lygeros, John
1995

SIRIUS (Systeme d'Information Routiere Intelligible aux Usagers) is the largest urban field operational test of the advanced traveler information and automated traffic management system in Europe. With variable message signs, SIRIUS has been in operation in the Paris region since December 1992. This study is a preliminary investigation of the effectiveness of the SIRIUS system in traffic management.The concern of the paper is the extent to which drivers respond to real-time traffic information and the consequential changes in link flow under SIRIUS. Time-series traffic data were analyzed...

Initial Scoping of Bay Area Smart Mobility Corridors and ITS World Congress

Shaheen, Susan
Finson, Rachel S.
McCormick, Cynthia
2004

The Innovative Corridors Initiative (ICI) is a multi-year project designed to encourage the early deployment of innovative technologies for Intelligent Transportation Systems (ITS) in California. ITS technologies are defined through a broad array of information and vehicle control technologies that are designed to improve traffic and transit management including safety, user choice, congestion, and incident response. For over a decade, ITS technologies have been gaining acceptance and are now utilized in every major metropolitan area in the United States to enhance transportation system...

Predictability of Time-Dependent Traffic Backups and Other Reproducible Traits in Experimental Highway Data

Smilowitz, Karen
Daganzo, Carlos
1999

Traffic data from a 4-mile long congested rural road in Orinda, California, are used to show that traffic delays and vehicle accumulations between any two generic observers located inside a road section can be predicted from the traffic counts measured at the extremes of the section. The traffic model does not require "recalibration" on the day of the experiment, and works well despite what appears to be location-specific driver behavior.