PATH

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...

Freeway Performance Measurement System, PeMS v3, Phase 1: Final Report

Varaiya, Pravin
2001

PeMS is a freeway performance measurement system for all of California.  It processes 2 GB/day of 30-second loop detector data in real time to produce useful information. Managers at any time can have a uniform, and comprehensive assessment of freeway performance.  Traffic engineers can base their operational decisions on knowledge of the current state of the freeway network.  Planners can determine whether congestion bottlenecks can be alleviated by improving operations or by minor capital improvements.  Travelers can obtain the current shortest route...

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...

Evaluating the Impact of ITS on Personalized Public Transit

Dessouky, Maged M.
Aldaihani, Majid
Shah, Rutvij
2002

The focus of this project is to study alternative system architectures and ITS technologies that can improve the efficiency of personalized public transit and demand responsive systems such as paratransit. This report reviews available and emerging ITS technologies that have been deployed or are being considered for this industry. We also conducted a survey of commercially available computer aided dispatching software. We list the numerous features offered by these software packages. Also, included in this report is a statistical analysis of travel patterns of a paratransit provider in Los...

Evaluating the Impact of ITS on Personalized Public Transit

Dessouky, Maged M.
Hall, Randolf W.
Shah, Rutvij
Aldaihani, Majid
2001

The focus of this project is to study alternative system architectures and ITS technologies that can improve the efficiency of personalized public transit and demand responsive systems such as paratransit. This interim report reviews available and emerging ITS technologies that have been deployed or are being considered for this industry. We also conducted a survey of commercially available computer aided dispatching software. We list the numerous features offered by these software packages. Also, included in this interim report is a statistical analysis of travel patterns of a paratransit...

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...

Southern California Intelligent Transportation System Priority Corridor Action Summary

Horan, Thomas
1999

The Southern California Intelligent Transportation System (ITS) Priority Corridor (Priority Corridor) represented a unique opportunity for the region. During the course of this federally sponsored six-year program, the region was able to develop a set of cooperative plans and actions that ensured the ongoing integration of the surface transportation system in Southern California. These directions are set forth in the Southern California ITS Priority Corridor Strategic Deployment Guide (Strategic Guide) and Southern California ITS Priority Corridor Action Summary (Action Summary).

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...