Roads/Highways

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...

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.

A Comparable Systems Analysis Of San Francisco's BART: Lessons For Automated Highway Systems

Hickman, Mark D.
1994

This study examines the lessons to be learned from the experience of the San Francisco Bay Area Rapid Transit (BART) system, particularly as applied to the growing research on automated highway systems (AHS). The first section of the report briefly motivates the analogy of BART by comparing some of the technical and non-technical performance factors surrounding both AHS and BART. Several pertinent technical and non- technical issues surrounding BART are described in more detail, emphasizing the decision-making that went in to BART's development, testing, and the beginning of revenue...

A Network Layer for Intelligent Vehicle Highway Systems

Eskafi, Farokh
Zandonadi, Marco
1999

The objective of this paper is to design the network layer of a communication stack to be used in Automated Highway Systems (AHS). The communication model we propose allows cars to form private subnets, the configuration of which can change dynamically. Each car be part of multiple subnets and can send broadcast, multicast and point-to-point messages to other vehicles (both on the same subnet and on others, through a routing mechanism). Each subnet is managed by a server: a car that is in charge of accepting/rejecting join requests and of keeping a consistent state within the subnet....

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...

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...

TravInfo Evaluation: Traveler Response Element Willingness to Pay for Traveler Information: Analysis of Wave 2 Broad Area Survey

Wolinetz, Louis
Khattak, Asad J.
Yim, Youngbin
2001

TravInfo is a Field Operational Test (FOT) sponsored by the Federal Highway Administration (FHWA) and California Department of Transportation. It aimed to develop a multi-modal traveler information system for the San Francisco Bay Area, combining public and private sector talents. The Broad Area Study is part of the TravInfo FOT evaluation. This paper addresses issues on the willingness to pay for traveler information. Two waves of telephone surveys of Bay Area households were conducted, one prior to and one after the Field Operational Test. The initial survey was conducted in November...

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...