PATH

California Transportation Management Centers Part 1. Assessment Of Existing Capabilities

Lo, Hong K.
Hall, Randolph W.
Windover, John R.
1993

Transportation Management Centers (TMCs) are focal points for monitoring and operating traffic management systems. As new technologies are developed through research in Intelligent-Vehicle- Highway Systems (IVHS), these TMCs will assume increasingly more importance as command and control centers for transportation operations. This study is aimed at developing visions for how the TMC of the future will exploit the capabilities of IVHS. Part 1 of this study, reported herein, is an assessment of existing TMC capabilities in the State of California. Part 2, to be reported later, will develop...

Assistive Devices and Services for the Disabled: Auditory Signage and the Accessible City for Blind or Vision-Impaired Travelers

Golledge, Reginald G.
Marston, James R.
Costanzo, C. Michael
1998

This project (MOU276) represents the first third of a longer project concerning making cities more accessible to some disabled groups by addressing some problems associated with the use of public transit. (The other two-thirds of the larger project is continued as MOU343). The disabled groups targeted in this project include the vision impaired or blind, those with low vision who have difficulty reading distant signs, those who are developmentally disabled, dyslexic, or otherwise print handicapped, those who do not read the English language, the illiterate, and small children. The blind or...

Relationships Among Urban Freeway Accidents, Traffic Flow, Weather and Lighting Conditions

Golob, Thomas F.
Recker, Wilfred W.
2001

Linear and nonlinear multivariate statistical analyses are applied to determine how the types of accidents that occur on heavily used freeways in Southern California are related to both the flow of traffic and weather and ambient lighting conditions. Traffic flow is measured in terms of time series of 30-second observations from inductive loop detectors in the vicinity of the accident prior to the time of its occurrence. Results indicate that the type of collision is strongly related to median traffic speed and to temporal variations in speed in the left and interior lanes. Hit-object...

Travinfo Field Operational Test Traveler Information Center (TIC) Study (technology Evaluation Element) Implementation Plan

Miller, Mark
Hall, Randolph
1995

TravInfo is a field operation test in the San Francisco Bay Area, designed to implement a centralized traveler information center to collect, integrate, and disseminate timely and accurate traveler information. The evaluation of TravInfo consists of four elements: institutional, traveler response, network performance, and technology. This document provides the implementation plan for the Traveler Information Center (TIC), part of the technology element, and also discusses how the TIC study will be coordinated with other evaluation elements.

BTS (version 1.0): Bottleneck Traffic Simulator User's Manual

Lin, Wei Hua
Hall, Ranolph W.
1991

Describes the computer program BTS which is a macroscopic tool for simulating the performance of freeway bottlenecks

Freeway Performance Measurement System: Final Report

Varaiya, Pravin
2001

PeMS is a freeway performance measurement system for all of California. It processes 2GB/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 and travel time estimates. Researchers can...

Safety and Efficiency Tradeoff Analysis for Automated Highway System: Part 3: Longitudinal Separation on AHS: A Trade-off Between Collision Probability/Severity and Capacity

Tsao, H.-S. Jacob
Hall, Randolph W.
1997

This report develops a probabilistic model for analyzing longitudinal collision/safety between an abruptly decelerating vehicle and its immediate follower on an Automated Highway System. The input parameters are the distance between the two vehicles, their common speed prior to the failure, the reaction delay of the following vehicle and a bivariate distribution for the two deceleration rates. The output includes the probability of a collision and the probability distribution of the relative speed at collision time. These safety consequences can be used to balance the desire to increase...

Modeling of the Brake Line Pressure to Tire Brake Force Subsystem

Xu, Z.
Ioannou, P.
1994

One of the most challenging problems in automated vehicle control is when and how to apply the brakes. In order to deal with such a problem, a good understanding of the dynamical behavior of the braking mechanism is essential. In this report we use experimental data from a series of tests performed in collaboration with Ford research engineers to modelthe brake line pressure to tire brake force subsystem. This model will be used together with that of the master cylinder to line pressure currently under study, for developing an overall model for the braking mechanism. The brake model will...

A Conceptual Approach for Developing and Analyzing Alternate Evolutionary Deployment Strategies for Intelligent Vehicle/Highway Systems

Al-Ayat, Rokaya
Hall, Randolph
1994

Intelligent Vehicle Highway Systems (IVHS) comprise a spectrum of technologies, with both short - term and long - term applications. Eventually, deployment of IVHS may lead to fully automated, hands-off and feet-off, driving. In the short - term, IVHS has included traffic control systems, in - vehicle information systems, and a range of new roadway sensors.This paper develops a framework for planning the evolutionary deployment of IVHS technologies. It defines an evolutionary deployment sequence, identifies baseline assumptions, and presents strategies for achieving success. This paper...

Evaluation Of Work Crew And Highway Hazard Conspicuity

Misener, Jim
1998

The report quantitatively addresses conspicuity of highway features, particularly in work zones, from the perspective of driver detection and driver decision making. The study focuses on evaluating the detection process, selecting and exercising human perception-acquisition models suitable for quick running and larger scale microsimulations to evaluate system effectiveness of pre-Automated Highway System (AHS) driver-assist systems. The report describes this process and provides a detection example of a driver-assist collision avoidance model.