PATH

Overview of 20 years of ITS Research in California

Zhang, W B
Misener, J
Skabardonis, A
2007

The California Partners for Advanced Transit and Highways (PATH) Program has been the largest ITS research program in the United States. It has been leading the way in ITS research since PATH's founding in 1986, before the term ITS or its predecessor IVHS (Intelligent Vehicle Highway Systems) had even been coined. PATH's purpose is to develop foundations for the widespread adoption of advanced technologies that will improve the operation of California's surface transportation systems. PATH's primary goals are to conduct research to reduce traffic congestion and improve mobility and safety...

Detection and Avoidance of Collisions: The REACT Model

Sauer, Craig
Andersen, George J.
Saidpour, Asad
2004

An important perceptual task during driving is the ability to detect and avoid collisions. Failure to accurately perform this task can have serious consequences for the driver and passengers. The present research developed and tested a model of car following by human drivers, as part of a general model under development of a human driver. Unlike other car following models that are based on 3D parameters (e.g., range or distance) the present model is based on the visual information available to the driver. The model uses visual angle and change in visual angle to regulate speed during car...

Approximate Method to Determine the Worst Case Performance of a Nonlinear Dynamical System

Tongue, Benson H.
Packard, Andrew
1998

This report presents the theoretical development of a method to evaluate differing platoon control strategies and determine each strategy's worst case behavior under bounded parametric variations. The approach is useful in aiding a platoon designer in determining the robustness a design strategy is in the face of system uncertainties. Index Terms: traffic platooning // safety // automated highways // vehicle dynamics.

A Communication Architecture for IVHS

Streisand, Susan L.
Walrand, Jean
1992

This paper documents the development of a communications architecture for Intelligent Vehicle Highway Systems (IVHS) being studied by the California PATH Program. The authors use a layered architecture based on the OSI 7- layer reference model.

A Conceptual Simulation Framework for Mobile Radio Communications: A Flexilevel Approach

Silvester, John A.
1997

Mobile radio communications systems are attracting more and more attention since they provide a means for users on the move to exchange information with other stationary or mobile stations. The capability of communication on the move can support many services and create lots of applications. For example, in the future Intelligent Vehicles Highway Systems (NHS), mobile communication technologies have enabled two important subsystems, namely Advanced Traffic Management and Information Systems (ATMIS) and Automatic Vehicular Control Systems (AVCS). The purpose of this research is to develop a...

Fault Tree Analysis of a First Example Automated Freeway

Hitchcock, Anthony
1991

This paper describes a fault tree analysis of an automated freeway and how conformity to safety criteria can be demonstrated by fault tree analysis. The system is initially explained, followed by a discussion of hazard analysis, fault tree, and an analysis of the results. Readers are advised to consult "Methods for Analysis of IVHS Safety: Final Report of MOU 19" by the author to acquire background information in regard to this report.

Commuters' Normal and Shift Decisions in Unexpected Congestion: En Route Responses to Advanced Traveler Information Systems Volume 2

Polydoropoulou, A.
Ben-akiva, M.
Khattak, A.
Lauprete, G.
1996

Advanced Traveler Information Systems (ATIS) are being developed to provide travelers with real-time information about traffic conditions. To evaluate the benefits of ATIS products and services, questions concerning potential market, usage, and travel response must be addressed. This paper focuses on en-route travel response to ATIS. The main objective is to explore how travelers deal with unexpected congestion and how they might respond to qualitative, quantitative, prescriptive and predictive information. Data on travelers’ route switching decisions are obtained through a survey of...

Real-time Estimation of a Markov Process Over a Noisy Digital Communication Channel

Xu, Qing
Sengupta, Raja
2005

We study the real-time estimation of a Markov process over a memoryless noisy digital communication channel. The goal of system design is to minimize the mean squared estimation error. We first show the optimal encoder and decoder can be memoryless in terms of the source symbols. We then prove the optimal encoder separates the real space with hyperplanes. In the case of the binary symmetric channel and scalar source, the optimal encoder can be a threshold. A recursive algorithm is given to jointly find a locally optimal encoder and decoder for the binary symmetric channel. For a memoryless...

PLANiTS: The Case-Based Reasoner as a Planning Tool for Intelligent Transportation Systems

Khattak, Asad
Kanafani, Adib
1995

This paper develops a data synthesis methodology in PLANiTS (Planning and Analysis Integration for Intelligent Transportation systems) using case- based reasoning. The reasoner contains mechanisms for matching, ranking and analyzing past cases in relation to current cases. The current cases consist of transportation improvement actions, performance measures and environments defined in terms of spatial, temporal and user dimensions. PLANiTS users can apply increasing levels of stringency to match cases. The authors also discuss issues related to computer implementation and the limitations...

Fault Detection and Identification with Application to Advanced Vehicle Control Systems

Douglas, Randal K.
Chung, Walter H.
Malladi, Durga P.
Chen, Robert H.
Speyer, Jason L.
Mingori, D. Lewis
1997

This report continues work on the design of a health monitoring system for automated vehicles. The approach is designed to fuse data from dissimilar instruments using modeled dynamic relationships and fault detection and identification filters. Issues relating to sensor models, output separability, steady-state fault persistence and the spectral content of sensor faults are considered.