PATH

Methodologies For Assessing The Impacts Of Highway Capacity Enhancements On Travel Behavior

Dahlgren, Joy
1998

Acceptance of ITS components that are designed to increase capacity will hinge on the extent to which additional capacity induces additional travel. This study addressed methodologies for studying the effects of capacity on travel: 1) before and after studies or travel times and volumes in corridors in which capacity had been increased, 2) surveys of users of routes on which capacity had been increased, and 3) statistical changes in county VMT as a function of freeway capacity. On I-80 in the Bay Area, the site selected for the investigation, travel times and volumes were quite variable....

Orange County Transit Probe Evaluation: Phase I Institutional Findings

Hall, Randolph W.
1997

This report documents the institutional issues that have faced the Orange County probe project, a multi-agency project designed to equip a fleet of buses with Global Positioning System (GPS) based tracking equipment and to use tracking data for multiple purposes. The usefulness of the data involve: 1) bus schedule adherence and fleet management; 2) collection of information on roadway traffic congestion; and, 3) dissemination of transit data to patrons.

A Focus Group Study of Automated Highway Systems and Related Technologies

Yim, Youngbin
1997

The paper presents the findings of a focus group study of the automated highway system and its related technologies, specifically adaptive cruise control and collision avoidance systems, in the San Francisco Bay Area. A majority of the participants had a favorable reaction to AHS despite the fact that almost all were concerned about its safety and funding capability. Responses to the adaptive cruise control were generally positive. The focus group participants recognized the safety benefits, the convenience, and especially the stress reduction of using the automated highway system, when...

Evaluation Framework For Commercial Vehicle Responses To Congestion Pricing

Wachs, Martin
Kawamura, Kazuya
1997

This report presents a short-run framework for analyzing the impacts of congestion pricing on commercial vehicles. The framework is based on microeconomics principles and past theoretical studies of congestion pricing. The relationship between value of time and the welfare gain/loss induced by using congestion pricing is identified. The social cost function and empirical demand and supply functions are also discussed.

Advances in Fuzzy Logic Control for Lateral Vehicle Guidance

Hessburg, Thomas
Tomizuka, Masayoshi
1994

A candidate for intelligent control for lateral guidance of a vehicle is a fuzzy logic controller (FLC). The details of the most recent FLC with a rule base derived from heuristics and designer insight to the problem at hand, as well as a method for estimating a projected lateral displacement are presented along with simulation results. The structure of this FLC is suited to incorporate human knowledge about the steering operation by its choice of inputs and outputs of the FLC which are natural to human steering operation. In addition, a method that makes use of preview information...

Transportation Opportunities and Constraints: The Performance of Urban Highway Transportation

Garrison, William L.
1987

This report is the first in a series. The objective of the series is the definition of opportunities for shafp improvements in highway system performance, say, improvements on the order of two or more. Toward that objective, this first report considers system performance as such and the status of the economic and social services enabled by the system.The report presents a first-pass analysis. Revisions are intended as the work continues.

Communication Requirements and Network Design for IVHS

Hsu, Ivy Pei-Shan
Walrand, Jean
1993

This paper presents the communication needs between vehicles and the roadside infrastructure for IVHS applications. The requirements of each application, in terms of message length, frequency, and acceptable delay, are estimated. Based on these estimates, we assess the amount of radio spectrum needed to support these applications. We find that about 1.2 MHz is required to support full highway coverage. We discuss the topology and capacity allocation problems for the road-based network and present one possible implementation. We show a case study of network design and link capacity...

Combined Brake and Steering Actuator for Automatic Vehicle Control

Prohaska, R.
Devlin, P.
1998

This report describes a combined steering and brake actuator system for use in automatic vehicle control research The system allows a standard passenger car to switch from normal manual operation to automatic operation and back in a seamless manner using largely standard parts. The system uses a constant flow actuator system which employs valves using standard constant-pressure spool valve bodies and custom spools. The technique minimizes the mechanical disruption to the vehicle and also allows a smooth transmission between modes.

High Occupancy Vehicle/Toll Lanes: How Do They Operate and Where Do They Make Sense?

Dahlgren, Joy
1999

Motivated by the need for better utilization of existing high-occupancy vehicle (HOV) lanes and the potential of high-occupancy/toll (HOT) lanes to increase utilization, this paper examines the circumstances in which HOT lanes could provide a more desirable alternative to HOV lanes. First, it compares the HOT and HOV lane concepts, showing how they are similar and how they differ. Both involve finding some type of equilibrium in which no additional people are motivated to use the lane. However, in the case of the HOT lane, the agency operating the facility can affect the equilibrium point...

Travel Time Estimation on the San Francisco Bay Area Network Using Cellular Phones as Probes

Ygnace, Jean-Luc
Drane, Chris
Yim, Y. B.
de Lacvivier, Renaud
2000

Current traffic travel time estimates are largely based on road sensors embedded in the pavement. Today technical developments in cellular positioning and the spread of wireless phones provide the opportunity to track cell phone equipped drivers as traffic probes. The Federal Communication Commission Phase II mandate for Enhanced-911 (E-911) requires that wireless carriers must provide the location of a 911 wireless call by October 1, 2001 to the Public Safety Answering Point (PSAP), within approximately 125 meters, or under one-tenth of a mile in the majority of situations. The motivation...