PATH

Ultrasonic Ranging Control Board Documentation

Chen, Jennie
Foreman, Bret
Mostov, Kirill
1994

This document specifies the theory of operation of version B of the PATH ultrasonic range control board for the IBM PC. Two modes are discussed in detail. The first is the ping mode, which uses a single transducer both to send an ultrasonic pulse and receive its echo. The second, called the phased-array mode, uses a single transducer to send the pulse and two other transducers to receive echoes and perform path-length matching in order to reduce the effects of multi-path echoes. Both the hardware and the software used to perform these functions are examined.

Transient Aerodynamics in Vehicle Interactions: Data Base Summary

Chen, A.L.
Hedrick, K.
Savas, O.
1998

The vehicles in a platoon will experience transient aerodynamic forces as vehicles leave and join the platoon at various locations. A platoon of scale vehicle models is placed in a wind tunnel and measurements are made of the transient forces and moments as one of the vehicles is moved into and out of the platoon. The results from the wind tunnel experiments will allow the computer vehicle control algorithms to better predict the transient aerodynamics the vehicles in the platoon will encounter during leaving and joining maneuvers.Since a lane change (either leaving or joining a platoon)...

Lessons From Case Studies Of Advanced Transportation And Information Systems

Dahlgren, Joy
Weissenberger, Stein
Hickman, Mark
Lo, Hong
1996

This paper poses two key questions regarding ATMIS implementation: how are ATMIS services successfully implemented?, in what circumstances are ATMIS strategies cost-effective? The authors attempt to find answers by examining case studies of twelve jurisdictions. The answers should help others judge where and how ATMIS should be implemented. The first section of the paper identifies the requirements for successful ATMIS implementation and operation based on the case study findings. The second describes a diffusion pattern found in the case studies. The final section concludes that more is...

Decision Support Systems for Managing and Applying ITS Research

Dahlgren, Joy
AlKadri, Mohamed
Picado, Rosella
1998

This study is presented in three related papers. The first develops a structure for making decisions regarding Caltrans/PATH research. It describes a research cycle in which real world needs and opportunities fed into a process by which research priorities are set, proposals invited, and projects are selected. These research projects ultimately provide information that can be used for further research or for implementation. Implementation changes society and technology and leads to new needs and opportunities, which in turn feed into the research process. The second paper develops and...

Identification and Prioritization of Environmentally Beneficial Intelligent Transportation Technologies: Modeling Effort

Young, Troy
Sperling, Daniel;
Shaheen, Susan
1999

In 1996, California Partners in Advanced Transit and Highways (PATH) commissioned a project team led by the Institute of Transportation Studies, University of California at Davis with the Claremont Graduate School to undertake a review of the environmental impacts of Intelligent Transportation Systems (ITS). The objectives of this project were to: 1) review previous qualitative and quantitative environmental assessments of ITS, from both field operational tests and modeling studies; 2) review the regulatory and policy contexts which encompass ITS; 3) develop a modeling framework suitable...

AHSCAP Dynamic Traffic Assignment Program User’s Manual and Design Description

Hongola, Bruce
1996

This research seeks to provide an understanding of the capacity and throughput require- ments of an automated highway system(AHS) via development of a computer model that represents system capacity and demand, operational characteristics, and defined infras- tructure. To do that, a variety of scenarios representing traffic input to the system must be represented. Also, a variety of infrastructures representing different system configurations must be represented. This includes the locations of entrances and exits.Detailed vehicle-based simulations have been used to investigate AHS capacity...

Fuzzy Logic Control For Lane Change Maneuvers In Lateral Vehicle Guidance

Hessburg, Thomas
Tomizuka, Masayoshi
1995

This paper investigates the feasibility of a fuzzy logic control (FLC) algorithm for lateral control in a lane change maneuver in an automated highway system (AHS). The lane change maneuver takes the vehicle from lane following control in one lane to lane following control in an adjacent lane. A lateral accelerometer is the only sensor used for feedback during the maneuver. The rules of the FLC are developed based on human driving experience.

Operations at Regional Traveler Information Centers: The Case of the TravInfo Field Operational Test - Final Results

Miller, Mark A.
Loukakos, Dimitri
2000

TravInfo is a regional traveler information system in the San Francisco Bay Area. It was a Field Operational Test (FOT) over a two-year period from September 1996 to September 1998 with funding from the Federal Highway Administration and the California Department of Transportation (Caltrans). TravInfo's goal was to broadly disseminate accurate, comprehensive, timely, and reliable information on traffic conditions and multi-modal travel options to the public in the Bay Area. Organizationally, it was structured around a collaborative partnership between and among public and private...

How the Reconstruction of I-880 Affected Travel Behavior

Dahlgren, Joy
2001

One of the concerns that people have about expanding highway capacity is that this will motivate more people to travel, so that the highway will soon become as congested as before. This is also a concern with automated vehicles, which would have the effect of increasing capacity. This so-called induced travel has been a subject of much debate and study in recent years. One of the problems confounding studies of this subject has been that capacity increases are generally motivated by recent or expected development, which generates increased travel and can even increase per capita travel if...

A Methodology for Developing a Traffic Surveillance Investment Program: An Application to Caltrans District 4

Dahlgren, Joy
2000

A method for determining how to develop the most effective traffic surveillance investment program given available resources is developed. The complicated decision structure for deciding where and when to install traffic surveillance and what type of surveillance to install is broken down into a series of steps: identifying information needs, determining which can be met by traffic surveillance, setting criteria for and evaluating the benefits of surveillance in various locations, identifying alternative surveillance methods and estimating their capabilities and costs, comparing the ratios...