PATH

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...

A Comparison of Traffic Models: Part II Results

Lo, Hong K.
Lin, Wei-Hua
Liao, Lawrence C.
Chang, Elbert
Tsao, Jacob
1997

This working paper is the second part of a series comparing dynamic traffic flow models. It documents the results of comparison based on the framework defined in Part 1. The traffic models selected for comparison are DINOSAUR, DYNASMART, INTEGRATION, and METS. The areas of comparison comprise four categories: functionality, traffic dynamics, route choice mechanism, and network performance.The first category was compared with a checklist of functions. A total of thirteen test scenarios were constructed to compare models for the last three categories.

Effect of Longitudinal Control on Capacity

Beji, Yousser
1987

This paper focuses on what benefits a longitudinal control system can be expected to render to the present highway system.There are three major reasons why longitudinal control should be expected to improve traffic flow and to reduce accidents.(1) It may permit higher traffic densities with uniform spacing forming an even distribution with increased travel speeds and consequently higher capacity.(2) It may reduce the rate of rear-end collisions that occur on urban freeways.(3) It can provide increased stability in traffic flow (shockwaves due to human response characteristics are the main...

PATH ATMIS State of the Research Annual Report Fiscal Year 1998 / 1999

Tam, Robert
1999

This report summarizes PATH ATMIS and Systems research for fiscal year 1998/1999. In each of the brief project descriptions we state the objectives of the project and outline its status and some of its principal results. These descriptions are not intended to be comprehensive or complete, but rather to present a picture of the main thrusts of each of the reported projects. References are provided in the end of the report for more detailed information about particular projects. Taken together, the collection of project descriptions should also give a reader an overview of the entire program...

TMDD Standards Update Recommendations – Data Structures

Peterson, Brian
2023

This document provides a set of recommendations for modernization of the Traffic Management Data Dictionary (TMDD) (1), currently at version 3.1. These recommendations are based upon the following: Connected Corridors project experience; three previous technical memorandums provided under this project discussing the current and future state of transportation, the state of the supporting technology for information exchange, and a review of the TMDD standard; a gap analysis based on the three technical memorandums delivered as part of this project. The intention of this document is to inform...

Lateral Control Of Commuter Buses

Hingwe, Pushkar
Tomizuka, Masayoshi
1995

This report presents two approaches to the design of the lateral controllers for commuter buses based on Sliding Mode Control (SMC). The objective of the control is to track the lane centerline. The first controller uses the sensor output which is a combination of yaw and lateral error. The second controller achieves tracking objective by providing a yaw rate to the vehicle so as to keep the lateral error dynamics stable. The two controllers are compared by performing simulations for a range of parameters.

Traveler Response to New Dynamic Information Sources: Analyzing Corridor and Area-Wide Behavioral Surveys

Yim, Youngbin
Khattak, Asad J.
Raw, Jeremey
2004

Intelligent Transportation Systems present a well-known innovation opportunity to address urban congestion and allow greater access to transportation networks. New sources of travel information are emerging rapidly and they are likely to significantly impact traveler decisions and transportation network performance. To assess the value and impact of these new sources, this paper develops a comprehensive conceptual model based on information processing and traveler response. Specifically, the model accounts for the effect of information source, content and quality on information access and...

Evaluation Methods for Measuring the Value of ITS Services and Benefits from Implementation: Part X Freeway Service Patrols

Levinson, David
Parthasarathi, Pavithra Kandadai
2001

The goal of our report is to determine the value that people place on the benefits offered by freeway service patrols in comparison to private assistance services and how much they would be willing to pay to avoid being stranded when their vehicle breaks down on the freeway. The report investigates the factors that contribute to people choosing to rely on the highway assistance services in comparison to the private assistance services. The studies conducted so far have focused on the effectiveness of the freeway service patrol whereas this report analyzes the factors that influence people...